Digimap Data: New datasets coming in the New Year

Posted on December 9, 2014 by Tom Armitage

The new Ordnance Survey Licence includes some new and very interesting datasets for the Digimap service. We have already added OS Terrain 5, Ordnance Survey’s most detailed digital terrain model and contour data to the the Data Download facility. The other new datasets will require some additional effort to add into the service but we should have them available to download early in the new year. These new datasets are as follows:

OS MasterMap ITN Urban Paths

Routing information for walkers and cyclists in towns and cities.

More Info from Ordnance Survey…

OS MasterMap Sites Layer

Identifies areas as being in categories such as schools, hospitals, transport facilities etc. The data also highlights access points to the sites and routing destinations for more accurate travel distances.

More Info from Ordnance Survey…

Points of Interest

Over 4 million points of interest classified into 3 tiers; 9 groups, 52 categories and 616 classes. The points of interest include accommodation, eating and drinking, commercial services, attractions, sport and entertainment, education and health, public infrastructure, manufacturing and production,retail, and transport.

More Info from Ordnance Survey…

EDINA has had many requests for these datasets, especially the Urban Paths so we are very pleased to be able to offer them to you. We also intend adding some of these datasets to Digimap Roam so that they can be added to the maps you view and print as well.

Please contact the EDINA help desk if you want access to the datasets mentioned above before they are made available in the Data Download service:

Phone: 0131 6503302
Email: edina@ed.ac.uk

Visualising OS MasterMapÂ® Topography Layer Building Height Attribute in AutoCAD Map 3D and InfraWorks

Posted on November 13, 2014 by Ian Holmes

We’ve recently written blogs on visualising OS MasterMapÂ® Topography Layer Building Height Attribute (BHA) data in ESRI’s ArcGIS and ArcGlobe and also QGIS. These blogs have proved very popular so we have written a 3rd instalment on how to achieve similar results using Autodesk products using AutoCAD Map3D and InfraWorks.

Please see the previous post for information on BHA data coverage, an explanation of the different height attributes supplied by Ordnance Survey (OS) and for details of further information sources; including the excellent Getting Started Guide produced by OS. Please remember this is an alpha release of the data and OS do not guarantee that BHA is error free or accurate. Additionally the dataset is not yet subject to update and maintenance.

Getting Started

Download the following datasets for your area of interest from Digimap using the OS Data Download application:

OS MasterMapÂ® Topography Layer: select â€˜GMLâ€™ as the format for your data rather than ‘DWG’ as we need to get to some of the raw data values stored in the GML file, and limit your download to just the Buildings using the Layers drop-down in the basket.
OS Terrainâ„¢ 50 DTM: this will be used as the base (surface) heights for the area;
BHA data (BHA data is found in the â€˜OS MasterMapâ€™ group): select CSV as the format;
Optionally download any additional data you may wish to use as a backdrop draped over the DTM surface, in this example we’re going to use OS MasterMapÂ® 1:2,000 Raster but other datasets could be used.

Preparing BHA data for use

If your downloaded BHA data is made up of more than one CSV file we recommend merging them all together in to a single CSV file first to make subsequent processing easier and quicker. Use a text editor such as Notepad or TextPad rather than Excel, as Excel can change the formatting of numbers which contain leading zeros.

Each object in MasterMap Topography Layer has a unique identifier called a Topographic Identifier, or TOID for short. TOIDs supplied by OS take the format of a 13 or 16 digit number prefixed with â€˜osgbâ€™ e.g. â€˜osgb1000039581300â€² or â€˜osgb1000002489201973â€². Some applications, including AutoCAD Map 3D , automatically strip off the â€˜osgbâ€™ prefix and add three leading zeros to any TOID that has only 13 digits to make them all 16 characters long. In order to make it easier to join BHA data to building features in MasterMapÂ® Topography Layer the BHA files supplied by EDINA have two TOID values:

os_topo_toid_digimapÂ is the TOID formatted to match TOIDs in AutoCAD Map 3D, ArcGIS and in the File Geodatabase format supplied through Digimap.
os_topo_toid is the original TOID as supplied by Ordnance Survey

You should check the TOID values in your MasterMap data and those in the BHA data to ensure that there is a common field that you can use to match on; we will use os_topo_toid_digimap as this field in the BHA data matches the TOID values in the MasterMap data when used in AutoCAD Map 3D.

Open the merged CSV file in Excel. To ensure that the data is displayed correctly in Excel you should import the data as follows:

Open a blank Excel document then use the ‘From Text’ option which can be found on the Data ribbon.Â This allows you to specify the correct field delimiter and data types for the TOID columns, ensuring they are imported as text fields, show image.
Import the data as a ‘delimited’ file, show image.
Specify ‘Comma’ as your delimiter, show image.
On the Text Import Wizard – Step 3 of 3 window select the first column in the ‘Data Preview’ section and set the ‘Column data format’ to ‘Text’. Repeat this step for the second column. This ensures that Excel treats the two TOID columns as text rather than numbers so doesn’t strip off the leading zero’s from any of the values (which are needed when joining the data to the building features in MasterMap later on), show image.
Press Finish to complete the process, after which your data in Excel should look like the image below with the TOID values in the first column all 16 characters long and including three leading zero characters where necessary:
AutoCAD Map 3D requires a ‘named range’ of cells to connect to. To create this highlight/select all cells that contain data in the workbook and using the ‘Name Box’ give this selection of cells a name. In the screen grab below we have called the selection ‘BuildingHeightValues’ (note your name cannot include spaces):
Save your file as an .xslx file.
The next step is to use the Windows ODBC Data Source Administrator to create a connection that points to this .xlsx file. Open the ODBC Data Source Administrator, the easiest way of doing this is to use the Windows search tool to search for ‘ODBC Data Source’.
On the ‘User DSN’ tab press the ‘Add…’ button to create a new ODBC connection:
Select ‘Microsoft Excel Driver’ and press the Finish button.
Give your connection a name in the ‘Data Source Name’ field, and using the ‘Select Workbook…’ button browse and select the .xlsx file created above.
Press OK and the newly created User DSN will be listed:
Press OK to close the ODBC Data Source Administrator.

Preparing MasterMap Topography Layer GML data for use

Open AutoCAD Map 3D.
At the command prompt type: MAPIMPORT, or select ‘Map Import’ from the Insert menu.
Browse to the .gz file downloaded from Digimap, ensure the ‘Files of type’ drop-down is set to ‘OS (GB) Mastermap (*.gml, *.xml, *.gz)’.
Import just the TopographicArea layer by deselecting all other layers in the import dialog.
Click on the word <None> in the Data Column for the TopographicArea layer.
In the Attribute Data window select ‘Create object data’ and press OK.
Select ‘Import polygons as closed polylines’ and press OK.
The data will be imported in to your current map window. Note you may need to select View > Extents to see the data.
The data needs to be converted to an .sdf file to allow the Building Height Attribute data to be joined to it.
1. At the command prompt type: MAPEXPORT
2. Select ‘Autodesk SDF (*.sdf)’ as the file type.
3. On the Feature Class tab, click on the ‘Select Attributes…’ button.
4. In the Select Attributes window select ‘Object Data’ and press OK.
5. On the Map Export window press OK to export the data.
Connect to the .sdf file just created:
1. In the Task Pane select Data > Connect to Data…
2. Select ‘Add SDF Connection’.
3. Give your connection a name and browse to the .sdf file exported in the previous step.
4. Click the Connect button to establish the connection.
5. Press the ‘Add to Map’ button to add this data to your current map window.

You have now added MasterMap buildings to your current map window, the next step is to connect to the Building Height Attribute (Excel spreadsheet) and join it to the building features in MasterMap.

Joining Building Height Attribute to buildings in MasterMap

Connect to the BHA spreadsheet using the ODBC connection:
1. In the Task Pane select Data > Connect to Data…
2. Select ‘Add ODBC Connection’
3. Give your connection a name and select the Data Source Name created above using the ‘…’ button next to the ‘Source’ field.
4. Press the ‘Test Connection’ button.
5. The table in the bottom half of the window will display all named ranges in your spreadsheet, we called our named range ‘BuildingHeightValues’. Before you can select this range for use in AutoCAD Map 3D you need to select a column to use as the ‘Identify Property’. To do this click on the text that says ‘<Click to select>’.
6. In the drop-down that appears put a tick in the box next to the value ‘os_topo_toid_digimap’.
7. Now you can tick the box next to the named range in the spreadsheet and press the ‘Connect’ button.
8. The connection details will be displayed.
9. The Data Connection window can now be closed.
In the Task Pane right click on the MasterMap data and select ‘Create a Join…’
In the ‘Create a Join’ window:
1. select the building height data (in the Excel spreadsheet) as the ‘Table (or feature class) to join to’;
2. select ‘TOID’ in the left hand drop-down menu;
3. select ‘os_topo_toid_digimap’ in the right hand drop-down menu;
4. select ‘Keep only left-side records with a match’ in the ‘Type of Join’ section;
5. press ‘OK’ to create the join.
To verify that the Join has worked, open the data table for the MasterMap data, this is done in the Task Pane by selecting the MasterMap data then pressing the ‘Table’ button. The table will be displayed, scroll to the right to see the joined building height values:
The final step is to export the joined data as a new .sdf file which we can then visualise in 3D in InfraWorks. This is done by either right clicking on the MasterMap layer in the Task Pane and selecting ‘Export Layer Data to SDF…’ or by using the ‘Export to SDF’ function on the ‘Vector Layer’ ribbon in the ‘Save’ group.

Visualising the data in 3D using Autodesk InfraWorks

So far we have downloaded OS MasterMapÂ® Topography Layer and BHA data for the same area and joined the two together to create a new dataset containing just the building features which now include the various height attributes published by OS. We also downloaded additional data to use as a backdrop draped over the DTM surface, in this example we will use OS MasterMapÂ® 1:2,000 Raster, but OS VectorMapÂ® Local Raster or OS 1:25,000 Scale Colour Raster would also be suitable depending on the scale of your study area.

Visualising the data in 3D is achieved using Autodesk’s InfraWorks product . The steps below describe how to use the application to create a 3D model:

Open InfraWorks and create a new model.
Specify a location to save the model and give it a name:
Click and drag the OS Terrain 50 DTM in to InfraWorks; the file to drag is the one with the .asc extension.
In the Data Source Configuration window, ensure the Type is set to ‘Terrain’ and Coordinate System is set to ‘BritishNatGrid’:
Press the ‘Close & Refresh’ button; the DTM should be displayed:
Click and drag the final .sdf file created in the final step of the previous section which contains the heighted building data (i.e. the .sdf file created after joining the MasterMap buildings to the Building Height Attribute data spreadsheet).
In the Data Source Configuration window, set the ‘Type’ drop-down to ‘Buildings’ and select a suitable ‘Roof Height’ attribute using the drop-down on the Common tab. As with previous blogs we have used the RelH2 attribute as we found this gave the best overall representation of building heights relative to each other:
On the ‘Geo Location’ tab select ‘BritishNatGrid’ as the coordinate system:
On the Source tab select ‘Drape’ from the drop-down under the ‘Draping Options’:
Press the ‘Close & Refresh’ button, the buildings should now be displayed on top of the DTM, you may need to pan or zoom to view the data:

OS Terrainâ„¢ 50 with buildings from OS MasterMapÂ® Topography Layer extruded on top using Building Height Attribute data.
To give some more context to the visualisation you can drape additional raster layers on top of the DTM such as OS MasterMapÂ® 1:2,000 Raster. This is done by selecting all the raster files and dragging them in to the InfraWorks window.
In the Data Source Configuration window ensure ‘Type’ is set to ‘Ground Imagery’, and one the ‘Geo Location’ tab select the ‘BritishNatGrid’ Coordinate System:
Select the ‘Close & Refresh’ button and the map data will be draped over the DTM surface:

OS MasterMapÂ® 1:2,000 Raster draped on top of OS Terrainâ„¢ 50, with buildings from OS MasterMapÂ® Topography Layer extruded on top using Building Height Attribute data.

The finished visualisation

The screen grab below shows the final visualisation centred on Biggar usingÂ OS MasterMapÂ® 1:2,000 Raster as the surface layer.

OS MasterMapÂ® 1:2,000 Raster draped on top of OS Terrainâ„¢ 50, with buildings from OS MasterMapÂ® Topography Layer extruded on top using Building Height Attribute data.

Visualising OS MasterMapÂ® Topography Layer Building Height Attribute in QGIS

Posted on November 6, 2014 by Ian Holmes

Our recent blog post about visualising OS MasterMapÂ® Topography Layer Building Height Attribute (BHA) data in ArcGIS and ArcGlobe prompted a number of questions about whether it’s possible to do something similar in open source software. In this post we’ll show you how to achieve something similar using QGIS and the freely available Qgis2ThreeJS plugin.

Getting started

Download the following datasets for your area of interest from Digimap using the OS Data Download application:
1. OS MasterMapÂ® Topography Layer: select the â€˜File Geodatabaseâ€™ format for your data as this format does not require any conversion to use it in QGIS;
2. OS Terrainâ„¢ 50 DTM: this will be used as the base (surface) heights for the area;
3. BHA data (BHA data is found in the â€˜OS MasterMapâ€™ group): select CSV as the format;
4. Optionally download any additional data you may wish to use as a backdrop, such as OS VectorMapÂ® Local Raster or OS 1:25,000 Scale Colour Raster;
Open QGIS and load in the OS MasterMapÂ® Topography Layer, OS Terrainâ„¢ 50 DTM and your backdrop map data.

Preparing BHA data for use

Each object in MasterMap Topography Layer has a unique identifier called a Topographic Identifier, or TOID for short. TOIDs supplied by OS take the format of a 13 or 16 digit number prefixed with â€˜osgbâ€™ e.g. â€˜osgb1000039581300â€² or â€˜osgb1000002489201973â€². Some applications, such as ArcGIS, automatically strip off the â€˜osgbâ€™ prefix and add three leading zeros to any TOID that has only 13 digits to make them all 16 characters long. Additionally this same formatting is applied to the File Geodatabase format of MasterMap supplied through Digimap. In order to make it easier to join BHA data to building features in MasterMapÂ® Topography Layer the BHA files supplied by EDINA have two TOID values:

os_topo_toid_digimapÂ is the TOID formatted to match TOIDs in ArcGIS and in the File Geodatabase format supplied through Digimap.
os_topo_toid is the original TOID as supplied by Ordnance Survey

Before BHA data can be loaded in to QGIS it is necessary to create a small text file (called filename.csvt, where ‘filename’ is the name of your BHA csv file) that specifies the data type of each field so that QGIS handles it correctly. Specifically the .csvt file is used to ensure that QGIS treats the two TOIDÂ values as text rather than numbers, and all height values as numbers. The steps required are detailed below:

Create a new file called filename.csvt (replacing ‘filename‘ with the name of your BHA csv file) in the same folder as the BHA csv file you wish to import.
Open the file in a text editor such as Notepad or TextPad.

Copy and paste the following text in to the file:

"String","String","Integer","Date","String","Real","Real","Real","Real","Real","Integer"

Save your changes to the file. Ensure it is saved in the same folder as the CSV file you wish to import.
Add your BHA CSV file to QGIS through the Add Vector Layer function; this will add the data as a table in the QGIS project.

Creating a heighted buildings dataset

In order to create a new heighted buildings dataset from the building features in OS MasterMap Topography Layer and the BHA data we use the GIS â€˜joinâ€™ function. A join links these two datasets together through a common unique identifier (the TOID) resulting in a set of buildings with height values stored as additional attributes.

Bring up the Layer Properties dialog for the Topographic Area layer in the MasterMap data either by double clicking on the layer in the Layer panel or by right clicking on the layer and selecting Properties from the pop-up menu.
Select the ‘Joins’ tab on the left hand side to display the join panel:
Press the green plus button to add a new join:
1. Select your BHA dataset as the ‘Join Layer’.
2. Select the correct TOID field that matches the TOIDs in your MasterMap data; as mentioned above we’re using os_topo_toid_digimap as the formatting of this matches the TOIDs supplied in the MasterMap data downloaded from Digimap in File Geodatabase format.
3. In the ‘Target Field’ select the attribute column that contains the TOIDs in your MasterMapÂ® data; by default this is called ‘TOID’ in MasterMap downloaded from Digimap.
4. Leave the checkbox selected to ‘cache join layer in virtual memory’ as this will speed up query and display of the data.
5. Press OK to create the join.
Press OK on the Layer Properties dialog to close the window.
Open the attribute table for the TopographicArea MasterMap layer to verify the join has worked. You will see the additional BHA columns at the end of the attribute table. Note you will see a lot of ‘null’ values in these additional columns as BHA values are only available for ‘building’ features (the TopograhicArea feature class contains features for everything, not just buildings).
Having joined the datasets together, before we can create a heighted buildings dataset we need to select only those buildings which now have height information. This is done using the QGIS ‘Select features using an expression’ button:
We are looking to select only features which have a value for the height attribute we wish to use in the 3D visualisation. As mentioned in the previous post, we have found that the ‘RelH2′ attribute provides a good representation of the height of buildings relative to one another. The expression used is shown below. Note the field name, in quotes below, is automatically created by QGIS by adding the BHA table name (NT27) to the attribute column name (RelH2) with an underscore between them:
```
"NT27_relh2" IS NOT Null
```
Having selected just the buildings that include height information we can now export these features as a new dataset by right clicking on the TopographicArea dataset in the Layer panel and selecting ‘Save As…’ from the pop-up menu.
Save the dataset as a new Shapefile in a suitable location, selecting the checkboxes ‘save only selected features’ and ‘add saved file to map’.
The newly created heighted buildings dataset will be added to your QGIS project; now it’s time to visualise it in 3D.

Visualising the data in 3D

So far we have downloaded OS MasterMapÂ® Topography Layer and BHA data for the same area and joined the two together to create a new dataset containing just the building features which now include the various height attributes published by OS. We also downloaded OS Terrainâ„¢ 50 DTM to use as the surface heights, 1:25,000 Colour Raster and OS VectorMapÂ® Local Raster to drape over the surface.

Visualising the data in 3D in QGIS is achieved using the Qgis2ThreeJS plugin, which can be installed using the QGIS plugin manager if you don’t have it already. The steps below describe how to use the plugin to create a 3D model:

Ensure you have all the data loaded in to your QGIS project that you wish to include in the 3D model, as a minimum you should have your DTM, the heighted buildings dataset and a suitable map layer to drape over the DTM.
Turn off all layers in the Layers panel apart from the surface you wish to drape over the DTM; the buildings will be styled using the Qgis2ThreeJS plugin.
Launch the plugin, which can be found on the Web toolbar.
Using the ‘DEM’ panel of the plugin select your DTM data as the ‘DEM Layer’, leave all other settings at their default values. Tip: by default the surface has a vertical exaggeration of 1.5, if you wish to reduce or increase this, the setting is configured on the ‘World’ panel of the plugin.
In the ‘Polygon’ panel of the plugin select your heighted buildings dataset and complete the following settings:
1. Z coordinate: set to ‘Height from surface’ – this will ensure the buildings sit on the DTM surface.
2. Under ‘Style’: ensure the ‘Object type’ is set to ‘Extruded’ and select the height attribute you wish to use for the extrusion using the ‘Height’ drop down; as mentioned above, we’re using the RelH2 attribute from OS which is in the column ‘NT27_relh2′ in our data.
3. Select suitable colours and transparency, we used a medium grey colour with 10% transparency to give a glasshouse effect.
Optionally specify an ‘Output HTML file path’ to save the resultant files. Whilst you’re experimenting we recommend you leave this blank and the plugin will save the data in a temporary location, when you’re happy with the result you can use this setting to save your final visualisation.
Press ‘Run’ to create the 3D model. Once it’s finished processing the model will open in your default web browser.

The plugin outputs an HTML file, along with a small number of accompanying files. The HTML file requires a WebGL compatible browser (WebGL is a method of generating dynamic 3D graphics using JavaScript), most modern browsers are WebGL compatible including IE 11, FireFox, Chrome, Safari and Opera, the Can I Use site offers further information on browser compatibility.

As the files are output as a web page, you can share the results of your work with colleagues without them needing to have any specialist GIS software, however you are not permitted to make the website publicly available as the html and javaScript files contain map data rather than just images of maps.Â The Licence does not permit the sharing of licensed data from Digimap with anyone other than registered users of the service: Digimap Licence

Tips

The plugin uses the extents of the current QGIS map canvas, so the bigger the area being displayed, the bigger the generated 3D scene and the slower it will display. We have found that areas of up to 10kmÂ² display okay, anything bigger tends to be a little slow to respond.
If you wish to define specific extents for your 3D scene instead of using the map canvas extents this can be done on the ‘World’ panel of the plugin.
Applying a vertical exaggeration to your buildings is achieved through the ‘Multiplier’ setting on the ‘Polygon’ panel of the plugin.
You can create 3D models of multiple layers. For example in the screen shot below the trees were created by selecting the ‘Positioned Non Coniferous Trees’ from the OS MasterMap Topographic Point layer. These were then added to the QGIS project twice. Using the plugin one of these layers was extruded as a brown cylinder with a radius of 0.75m and a height of 3m to form the trunk; the other was extruded as a green sphere with a radius of 4.5m and a z coordinate of 4.5m (i.e. the height above the ground surface of the centre of the sphere) to form the tree canopy:

OS VectorMapÂ® Local Raster draped on top of OS Terrainâ„¢ 50, with buildings from OS MasterMapÂ® Topography Layer Building Height Attribute and Positioned Non Coniferous Trees extruded on top

The finished visualisation

The screen grab below shows the final visualisation centred on the south side of Edinburgh using OS 1:25,000 Colour Raster as the surface layer.

1:25,000 Colour Raster draped on top of OS Terrainâ„¢ 50, with buildings from OS MasterMapÂ® Topography Layer extruded on top using Building Height Attribute data.

OS MasterMapÂ® now available in File Geodatabase format from Digimap

Posted on October 31, 2014 by Tom Armitage

To get the most from OS MasterMap data it is usually best to convert it from its supplied format, GML, to a format better suited to the software you are going to use it in. For our CAD users Digimap has been offering the DWG format for several months (see previous blog post); now we are offering a format that makes the data easier to use in GIS software.

Although Shapefile is still the most commonly requested GIS format it cannot handle the large file sizes (over 2GB) that could be requested from the Data Download service; an area of 100km2 in an urban centre would exceed this limit.Â We therefore turned to the File Geodatabase format that works in the two most commonly used GIS software applications, ArcGIS and QGIS. There is more information about Geodatabases on Wikipedia here: Wikipedia -ArcGIS Geodatabase

To select the File Geodatabase format, add some MasterMap to your basket in Data Download. Once in the basket you can click the down arrow in the Format column and change it from the default GML to File Geodatabase:

Geodatabase formats are the recommended formatsÂ for use in ArcGIS software, being the most efficient for data storage and analysis. The format supports the use of .lyr files for styling the data and EDINA has provided some for the MasterMap data downloaded from Digimap.

The data can be added to a map in ArcGIS and QGIS in the usual way, though in QGIS you need to use Add vector layer –> Directory rather than a Database as you may assume.

Styling information for both ArcGIS and QGIS has been provided by EDINA in .lyr and QML formats, these can be found at the bottom of Digimap’s help page for OS MasterMap. These representations give enough information to view the data in a style that OS MasterMap is commonly viewed in. The help page also contains a link to the official Ordnance Survey SLD styling information, please see the PDF that comes with the SLD files for information on how to use them.

Digimap Help: OS MasterMap

There are help pages for adding styling information here:

If you require any help on using File Geodatabases from Digimap or any other dataset or format then please get in touch:

Phone: 0131 650 3302
Email: edina@ed.ac.uk

Visualising OS MasterMapÂ® Topography Layer Building Height Attribute in ArcGIS and ArcGlobe

Posted on October 22, 2014 by Ian Holmes

In March 2014 Ordnance Survey (OS) published an alpha release of the much anticipated Building Height Attribute (BHA) dataset, which is an enhancement to OS MasterMap Topography Layer. You can read all about it in their blog post. In this blog weâ€™re going to show you how to integrate the BHA dataset with buildings in the OS MasterMap Topography Layer to create a heighted buildings dataset and visualise it in 3D. We used ArcGIS 10.2 and ArcGlobe to do this but other software could be used.

The first alpha release of BHA included buildings covering approximately 8,000km2 of the country. A second alpha release of BHA was published in July 2014 which covers around 10,000km2 of the major towns and cities in Great Britain. OS publish an interactive map which shows the extents of the areas covered by the alpha release, so you can check if your area of interest is included.

A note of caution, this is an alpha release of the data and OS do not guarantee that BHA is error free or accurate. Additionally the dataset is not subject to update and maintenance. However in time OS intend to include BHA in OS MasterMap Topography Layer so in future it will be supplied and maintained as a part of the Topography Layer.

Attributes supplied by OS

A number of attributes are provided for each building as shown in the image :

ground level [AbsHMin]
the base of the roof [AbsH2]
highest part of the roof [AbsHMax]

Using these three values two additional relative heights are calculated:

relative height from ground level to the highest part of the roof [RelHMax]
relative height from ground level to base of the roof [RelH2]

Data availability

OS publish the data as a single CSV file containing over 20 million records. This is a very large dataset and can cause data management problems in a desktop environment so EDINA have split the dataset up using the OS 5km grid allowing you to download the data in tiles for your study area. The data is available in CSV and KML formats. To use the data in GIS or CAD packages you should download the data in CSV format; KML is used to visualise the data in Google Earth.

The â€˜Show Grid/Overlayâ€™ menu on the right hand side in the Data Download application displays the OS 5km grid. This will draw a grid with each square containing the OS 5km tile reference, as shown in the image.

Please note: BHA data is not currently available for the whole country, you should consult theÂ interactive map published by the OS to see if data exists for your area of interest.

Using the data

OS provide an excellent Getting Started Guide which explains in detail the process of getting BHA data in to GIS for subsequent analysis. The main steps are described below but please refer to the Getting Started Guide for full details.

The data is supplied as CSV files. Each record in the file has a unique TOID which can be used to join the data to building features in OS MasterMap Topography Layer.

Getting started

Download OS MasterMap Topography Layer data for your area of interest from Digimap using the OS Data Download application. Select the ‘File Geodatabase’ format for your data as this is a native ArcGIS format and doesn’t require any conversion.
Download BHA data for your area of interest from Digimap using the OS Data Download application (BHA data is found in the ‘OS MasterMap’ group), selecting CSV format.
Open the OS MasterMap Topography Layer data in ArcGIS.

Preparing BHA data for use

Each object in MasterMap Topography Layer have a unique identifier called a Topographic Identifier, or TOID for short. TOIDs supplied by Ordnance Survey take the format of a 13 or 16 digit number prefixed with ‘osgb’ e.g. ‘osgb1000039581300′ or ‘osgb1000002489201973′. ArcGIS automatically strips off the ‘osgb’ prefix and adds three leading zeros to any TOID that has only 13 digits to make them all 16 characters long. In order to make it easier to join BHA data to building features in MasterMap Topography Layer the BHA files supplied by EDINA have two TOID values:

os_topo_toid_digimapÂ is the TOID formatted to match TOIDs in ArcGIS
os_topo_toid is the original TOID as supplied by Ordnance Survey (this should be used in other GIS packages such as QGIS which do not modify the TOIDs in MasterMap Topography Layer)

Before BHA data can be loaded in to ArcGIS it is necessary to create a small text file (called schema.ini) that specifies the data type of each field so that ArcGIS handles it correctly. Specifically the schema.ini file is used to ensure that ArcGIS treats the two TOIDÂ values as text rather than numbers. The steps required are detailed below:

Create a new file called schema.ini in the same folder as the BHA csv file you wish to import.
Open the file in a text editor such as Notepad or Text pad.

Copy and paste the following text in to the file:

[bha_filename.csv]
Format=CSVDelimited
ColNameHeader=True
Col1=OS_TOPO_TOID_DIGIMAP Text
Col2=OS_TOPO_TOID Text
Col3=OS_TOPO_VERSION Long
Col4=BHA_ProcessDate DateTime
Col5=TileRef Text
Col6=AbsHMin Double
Col7=AbsH2 Double
Col8=AbsHMax Double
Col9=RelH2 Double
Col10=RelHmax Double
Col11=BHA_Conf Long

The first section of code, in square brackets shown in red above, refers to the name of the csv file you wish to import. You should modify this filename so that it references your BHA csv file.
Save your changes to the file. Ensure it is called schema.ini and is saved in the same folder as the csv file you with to import.
Add your BHA csv file to ArcGIS through the Add Data function; this will add the data as a table in the map document.

Creating a heighted buildings dataset

In order to create a new heighted buildings dataset from the building features in OS MasterMap Topography Layer and the BHA data we use the GIS ‘join’ function. A join links these two datasets together through a common unique identifier (the TOID) resulting in a set of buildings with height values stored as additional attributes.

Right click on the Topographic Area layer in the table of contents > Joins and Relates > Join. This will bring up the Join Data window which can be completed as shown. Remember to join to the TOID in the csv file that is formatted to match the TOIDs displayed in ArcGIS (os_topo_toid_digimap).
Tip: to create a dataset which just includes the heighted buildings select ‘Keep only matching records’.
Having joined the datasets together we can then export the result as a new Feature Class in our File Geodatabase for subsequent use and analysis. This is done by right clicking on the Topographic Area layer in the table of contents > Data > Export Dataâ€¦Â give your new dataset a suitable name and select your existing File Geodatabase as the destination.

Visualising the result in ArcGlobe

So far we have downloaded data from OS MasterMap Topography Layer and BHA data for the same area and joined the two together to create a new dataset containing just the building features which now include the various height attributes published by OS. Now the fun begins!

We can easily visualise the heighted buildings dataset in 3D using ArcGlobe or ArcScene. The following steps describe how to import the data in to ArcGlobe.

Download the OS Terrain 50 DTM for your area of interest from Digimap using the OS Data Download application. This will be used as the base (ground) heights for the area to provide a more accurate terrain model than is available by default in ArcGlobe.
Open ArcGlobe and add in the DTM. You will be asked if you wish to use the DTM as and â€˜image sourceâ€™ or an â€˜elevation sourceâ€™. You should select the â€˜elevation sourceâ€™ option:

The Geographic Coordinate Systems Warning dialog will appear as OS MasterMap Topography Layer data is in a different coordinate system (British National Grid) from that used by ArcGlobe (WGS 84):

You should specify the transformation used to ensure that the data is accurately positioned on the globe. Using the Transformationsâ€¦ button you should specify the â€˜OSGB_1936_To_WGS_1984_Petroleumâ€™ transformation:

Adding your heighted building dataset from your File Geodatabase is achieved through the Add Data button. Once added you may need to zoom to the layer to view it: right click on the layer in the table of contents > Zoom To Layer.
By default the data is not extruded vertically so appears flat on the earthâ€™s surface. To visualise the buildings in 3D right click on the layer in the table of contents and select Properties and then click on the Globe Extrusion tab.
Select the â€˜Extrude features in layerâ€™ checkbox and then in the â€˜extrusion value or expressionâ€™ box enter the following:

[relh2] * 1.5

This will extrude the buildings using the RelH2 attribute with a vertical exaggeration of 1.5 times (i.e. buildings will be shown 1.5 times their actual height). We found using RelH2 (the relative height from ground level to base of the roof) provides a more useful visualisation over RelHMax (the relative height from ground level to the highest part of the roof) which can lead to some overly tall looking buildings where they include towers that extend significantly beyond the height of the rest of the roof.

The end result

The image below shows an area of Edinburgh including Edinburgh Castle with Arthursâ€™ Seat in the background. Aerial imagery from ArcGlobe is draped over OS Terrain 50 data for the region with heighted buildings drawn on top. Using the tools in ArcGlobe it is easy to explore the landscape, navigating across the surface and examining the relationships between buildings in the built environment.

Further information

OS published Release Notes for the alpha releases of BHA. Additional information can be found in Annexe D of the OS MasterMap Topography Layer User Guide and Annexe E of the OS MasterMap Topography Layer Technical Specification.

Ordnance Survey Maps Updated: September 2014

Posted on September 25, 2014 by Tom Armitage

Even though we update our mapping data throughout the year we still make a large number of changes over the summer.

Along with the general updates to MasterMap and a few other products the biggest change over the summer has been to swap the 1:10 000 Scale Raster maps to VectorMap Local Raster maps in Digimap Roam. Ordnance Survey have retired the 1:10 000 data, so we have removed it from the online maps, though you do still have a couple of options if you are a fan of the product:

You can view the VectorMap Local data styled to look like the 1:10 000 maps at two zoom levels in Roam; remember that on the Map Content tab you can remove the contours for a very close representation of the mapping.
We still make the 1:10 000 data available in Digimap’s Data Download interface, and will continue to do so for at least this academic year.

The table below details all of the latest changes we have made showing the currency dates of all Ordnance Survey datasets in Digimap.

Digimap Roam

Ordnance Survey product	Data Currency	Last updated in Roam
OS MasterMap^Â® Topography Layer	May 2014	July 2014
OS VectorMap^Â® Local	July 2014	September 2014
OS VectorMap^Â® Local Raster	July 2014	September 2014
1:25 000 Scale Colour Raster	March 2014	March 2014
1:50 000 Scale Colour Raster	June 2014	July 2014
Meridianâ„¢ 2	January 2014	March 2014
OS Terrainâ„¢ 50	July 2013	October 2013
OS VectorMap^Â® District Raster	September 2014	September 2014
Strategi^Â®	January 2014	March 2014
1:250 000 Scale Colour Raster	June 2014	September 2014
MiniScale^Â®	January 2014	February 2014

Data Download

Ordnance Survey product	Data Currency	Last updated in Data Download
OS MasterMap^Â® Integrated Transport Networkâ„¢ (ITN) Layer	May 2014	September 2014
OS MasterMap^Â® Topography Layer	May 2013	September 2014
OS MasterMap^Â® Topography Layer Raster	June 2013	October 2013
Backdrop Mapping
* 1:10 000 Scale Raster	June 2013	October 2013
OS Street View^Â®	April 2014	April 2014
1:25 000 Scale Colour Raster	March 2014	March 2014
OS VectorMap^Â® Local Raster	July 2014	September 2014
OS VectorMap^Â® District Raster	September 2014	September 2014
1:50 000 Scale Colour Raster	June 2014	July 2014
1:250 000 Scale Colour Raster	June 2014	June 2014
MiniScale^Â®	January 2014	January 2014
Land and Height Data
* Land-Form PROFILE^Â®	November 2009	September 2011
* Land-Form PROFILE^Â® DTM	November 2009	September 2011
OS Terrainâ„¢ 50	July 2014	September 2014
OS Terrainâ„¢ 50 DTM	July 2014	September 2014
* Land-Form PANORAMA^Â®	November 1993	September 2011
* Land-Form PANORAMA ^Â® DTM	June 2006	September 2011
Vector Data
OS VectorMap^Â® Local	July 2014	September 2014
OS VectorMap^Â® District	September 2014	September 2014
Meridianâ„¢ 2	January 2014	February 2014
Strategi^Â®	January 2014	February 2014
Boundary and Location Data
Boundary-Lineâ„¢	May 2014	May 2014
Code-Point^Â®	August 2014	September 2014
Code-Point^Â® Open	August 2014	September 2014
Code-Point^Â® with polygons	April 2014	July 2014
OS Locatorâ„¢	May 2014	May 2014
1:50 000 Scale Gazetteer	June 2014	June 2014

* Land-Form PANORAMA^Â®, PROFILE^Â® and 1:10 000 Scale Raster products have been withdrawn by Ordnance Survey and are no longer updated.

Other Updates

Remember there have also been substantial changes made to the Geology and Marine data holdings in recent months:

Please also note that there are a lot more formats available than before so you may not have to convert the data after you have downloaded it:

It is now easier to see which formats are available for the data product you are downloading and change it if you need to, this blog post shows you how:

Digimap Download Basket Updates

Please let us know if you have any questions about the new data or any other changes and additions to the Digimap service

Email: edina@ed.ac.uk
Phone: 0131 650 3302

Digimap Download Basket Updates

Posted on September 24, 2014 by Tom Armitage

We have updated all the new style Download interfaces in Digimap to make it easier to change the options for the data you have selected. When you have added some data to your basket you can now see more clearly what can be changed; the version (date and style), the format and the layers.

Where these options are highlighted in blue with a â–¼ next to them you can click them and get a drop down menu with the alternatives.

New Download basket with open menu

Make the changes you need, add a name,Â then click on the Request Download button to order your data.

We have also made a slight change to the Product Information pages for some of the data products too.Â Where the data is available on tiles you can now click a Show Grid button to see the tile outlines on the map.Â When you make a selection on the map you will get all the grid tiles that are partially or entirely within your orange selection area.

This feature is particularly useful for data products like the 1:10,000 and 1:25,000 scale geology data and the Marine HydroView Charts, where the data isn’t a continuous coverage and your selected area may contain no tiles. When you click the Show Grid button it will also automatically open the menu from the right of the map which allows you to change the grid shown or switch it off.

Remember, you open the Product Information panels by clicking on the blue Info links in the list of data products to the left of the map.

Please let us know if you have any questions about these changes or anything else:

Email: edina@ed.ac.uk
Phone: 0131 650 3302

Digimap now has OS MasterMap data in CAD format

Posted on April 9, 2014 by Tom Armitage

Until now anyone wanting to use OS MasterMapÂ® Topography data in CAD software would have to convert their data, often a lengthy and complicated process.Â Now you can simply download the OS MasterMap Topography Layer in DWG format directly from Data Download. The DWG data should open in most CAD software such as AutoCAD, Vectorworks and ArchiCAD.

We always knew it wasn’t that easy to convert OS MasterMap data for use in CAD, the conversion software has a lot of options and can confuse at the best of times. The conversion software also doesn’t work on Apple Mac computers which are a popular choice with CAD users. However, we redoubled our efforts to provide DWG format data when we heard that some of our users were making PDF maps of OS MasterMap data and then manually digitising them from the screen… something had to be done!

Incorporating a conversion process into Data Download has not been simple and can produce some very large file sizes, especially if you need data for a busy urban area. Please only take enough OS MasterMap as necessary, or your computer may run out of memory when you work with the data.

How to get DWG OS MasterMap

To get your data in DWG format simply follow the usual steps for making an order in Data Download:

How to Use Data Download

Once you have added your OS MasterMap Topography data to the Basket, click on the “Change” link to access all the options for the MasterMap data.

Use the format section, bottom left to select DWG format instead of the default GML.

Your OS MasterMap data will not need any conversion to open in most CAD software, enjoy playing with the vectors!
Please let us know if you have any problems using this data or if you have suggestions as to how it could be improved.

Email: edina@ed.ac.uk
Tel: 0131 650 3302

Map updates in Digimap Roam

Posted on October 25, 2013 by Tom Armitage

We have updated three of the mapping datasets in Digimap Roam, so you can now view mapping published as recently as June 2013.

The products updated are:

OS MasterMap: used in the three most detailed zoom levels in Roam.
OS VectorMap Local (VML): the next most detailed maps in Roam, available as alternate “Basemaps” in the 4th and 5th most detailed zoom levels.
Midscale Maps: These maps are made of the Meridian 2 mapping data along with contours. Until now they had been made with Land-form PANORAMA data, but now they use the new OS Terrain 50 contours:

These midscale maps are also available in a backdrop colour scheme which can be accessed by using the Basemaps tab at the top right of the map. The faded colours allow your annotations to show more strongly:

The updated datasets are also available from Digimap’s Data Download service (except MasterMap which will follow in the next few months), a page in Digimap Help details the all the OS products available and their currency in Roam and Data Download:

Dates of Updates to Digimap

If you have any questions about the new data or any other issues relating to Digimap then please let us know:

Email: edina@ed.ac.uk
Tel: 0131 65o 3302

Making Digimap data easier to use: OS VectorMap Local

Posted on July 22, 2013 by Guy McGarva

As part of ongoing efforts to improve the usability of data delivered by Digimap, we have made some significant enhancements to one of the Ordnance Survey licensed datasets.

OS VectorMap^® Local is a relatively new product from Ordnance Survey providing slightly less detail than OS MasterMap but still very useful for detailed backdrop mapping. Individual buildings are shown as well as roads, rivers, landcover and contours. The vector version of the data is provided by Ordnance Survey in GML 2.1.2. This is a standard geospatial data format developed by the Open Geospatial Consortium; however it generally needs to be converted into a proprietary format before being used in GIS and CAD software.

To make using this data easier we are now providing OS VectorMap Local in both Shapefile and DWG formats. Shapefiles can be easily opened in ArcGIS and most other GIS programs including OpenSource GIS software such as QGIS and gvSIG. DWG is the native format for AutoCAD and can be used in many other CAD systems as well.

This data is now available for download from the Data Download application in the Digimap Ordnance Survey Collection. VectorMap Local is in the Vector Data section; to change the format of the data you are downloading click on the Change link under Options once you have added it to the basket.

Click image to view full size.

Creating the data:

TO achieve the best results when recreating the data in different formats we had to use different software products for different formats. To convert the data to Shapefile we used the OpenSource Software GDAL program called “ogr2ogr” and for the DWG conversion we used FME from Safe Software. The image below shows part of the FME Workbench project used to convert the data to DWG.

Image showing FME Workbench converting GML to DWG

Click image to view full size.

1: Shapefiles

To convert the GML to Shapefile we created a lookup table between the Feature Codes in the GML data to Shapefile Layers. As Ordnance Survey do not provide any guidance in their User Guide as to how to group features in VML , we analysed the data and experimented with various groupings, so that in the end we split the data into a possible 22 separate Layers. These layers may contain multiple feature classes but as they all have the original feature codes on them as attributes as well as all the other original attribution, further distinction between features can be achieved for representation and querying.

Example of the Shapefile data in ArcMap:

Click image to view full size.

A simple set of Layer Files has been created for use in ArcMap and can be downloaded from the VML Help page.

2. DWG

To convert the data to DWG we had to go through a similar process (as well as our data team becoming much more familiar with AutoCAD). We originally intended to produce DXF format data but this turned out to be a problem. We had to make some decisions about how to store attribution in the output data and one of the main considerations was the size of the resultant files. To begin with when we converted a tile of VML that was 60Mb of GML, it expanded in size to 240Mb when converted to DXF containing attributes as Inserts. This was unusable in systems we tried so we had to work on ways of making the files smaller. The first thing we did was change the format from DXF to DWG. As both formats are commonly read by various CAD systems this seems a reasonable thing to do although it may make the data slightly less interoperable. This changed the file size to 44Mb for our sample dataset. This was still quite large and some systems were having problems with this, especially when dealing with tiles in dense urban areas. We therefore decided to change the way we were storing attributes in the data. Instead of using Inserts we used Extended Entity Data (or XData) which was one of the options available in FME. This stores a fixed amount of information against an entity in the drawing. We use this to store the attribute information that was in the original GML data, including the original feature code. It’s a bit more difficult to work with this data but it can be viewed in AutoCAD Map 3D by using the Express Tools –> Tools –> List Object Xdata or typing xdlist in the command prompt.

Using XData brought the size of our sample tile down to 10Mb and was usable in all the systems we tested it with. If you need access to the attributes either as Inserts or as Map 3D Object data please let us know.

As part of the conversion process we defined the representation for features in the DWG file, including point symbols and area fills. Features have also been grouped together into separate Layers as we did with the Shapefiles.

Example of the data in AutoCAD:

Click image to view full size.

Finally, after getting the project set up in FME and a thorough testing of the data, we ran the batch process to convert the data. This took nearly 3 days per format to convert the full load of our national coverage of VML data. This data will be updated on the normal update schedule, as we get updated VML from Ordnance Survey as Change Only Updates so future conversions will be much quicker.

Remember,both these datasets are available through Data Download by selecting VectorMap Local and then changing the format after you have added the data to your basket.

We intend to produce alternative formats for other products, including OS MasterMap, so we would very much like to hear your thoughts on the data that we have produced so far and let us know if this meets your needs.