6. Installation and first usage

6.1. Requirements

sDNA requires Windows XP or later. We suggest a minimum of 1GB RAM, but obviously faster computers and more memory will be of use in analyzing larger networks. sDNA can run in 32- or 64-bit mode depending on the host application.

The toolbox can be used in any of a number of ways:

  • As a plug-in to ArcGIS 10.1 or later, or
  • As a plug-in to ArcGIS Professional, or
  • As a plug-in to QGIS 2.0 or later, or
  • As a plug-in to Autocad (various versions; 2010-2013 have been tested), or
  • From the windows command line, or
  • From sdnapy, the python API to sDNA.

Note that Autocad usage is limited to network shape analysis using sDNA Prepare and Integral. For more detailed analysis, we recommend using Autocad Map3d or other suitable software to convert CAD to 3d Shapefile, then processing in the free QGIS.

6.2. Installation

sDNA Open can be downloaded an installed from Github. You will need a serial number; these can be obtained for free.

Further steps are then needed depending on how you plan to use sDNA.

6.3. Using sDNA for the first time

How you use sDNA depends on your host application.

ArcGIS 10.x

  1. From inside ArcGIS, go to ArcToolbox.
  2. Right click the root of the ArcToolbox tree and choose Add Toolbox...”.
  3. Navigate to the place you have installed sDNA (usually c:\Program Files (x86)\sDNA) and select the toolbox sdna.pyt.
  4. (Optional) Repeat steps 2 and 3 to add the toolbox sDNA_ArcGIS_extra_tools.tbx.
  5. (Optional) To permanently add sDNA to ArcToolbox, right click the root of ArcToolbox and choose Save settings → to Default.

sDNA appears as a set of tools within ArcToolbox. Results can be displayed using the Symbology tab of the Layer Properties dialog. If you are not familiar with using tools from ArcToolbox, or changing layer symbology, visit the ArcGIS Desktop Help website for further details.

ArcGIS Professional

In ArcGIS Professional, external toolboxes appear in the Catalog rather than with ESRI’s own geoprocessing tools.

  1. From inside ArcGIS, navigate to the “View” ribbon and choose “Catalog Pane” to open the catalog.
  2. In the Catalog pane, right click on “Toolboxes”, Choose “Add Toolbox”
  3. Navigate to the place you have installed sDNA (usually c:\Program Files (x86)\sDNA) and select the toolbox sdna.pyt.

The tools can then be used from the catalog.

QGIS

  1. From inside QGIS, choose Plugins → Manage and install plugins.... At present, QGIS support is considered experimental, so go to Settings and click Also show experimental plugins.
  2. Type “sdna” into the search box; you should find the Spatial Design Network Analysis plugin. Different sDNA plugins should appear depending on which version of QGIS you are using (2 or 3).
  3. Click Install Plugin, then Close
  4. Go to Processing → Toolbox to show the processing toolbox
  5. At the bottom of the processing toolbox, change from Simplified interface to Advanced interface
  6. “Spatial Design Network Analysis” should now appear in the processing toolbox
  7. Go to Processing → Options → General and ensure Keep dialog open after running an algorithm is switched on.

Results of sDNA operations can be displayed using layer styles. After running sDNA, right-click the relevant layer in the layers panel, choose Properties → Style, change Single Symbol to Graduated and select the data you want to display.

Autocad

When we originally created sDNA, we envisaged urban designers using it via Autocad. As sDNA has become more advanced, the data handling capabilities of Autocad no longer support all the features we offer; in particular, use of user data attached to links is not possible. We are not fixing this because the Urban Design world mostly uses BIM systems these days, and we plan to implement sDNA for BIM in future. If you are interested in this possibility, please get in touch with us!

If you are an Autocad Map3d user, there is a workflow for using fully featured sDNA models that involves exporting/importing data from the free QGIS. See our notes on Advanced sDNA models in Autocad Map3d.

For other products in the Autocad family, use of basic models (without user data) is supported. Installation is as follows:

  1. On your start menu, in the sDNA program group, click on Register sDNA for Autocad (32 or 64 bit depending on your Windows installation). You may need to provide an administrator password.
  2. From the Ribbon, choose Manage → Load Application
  3. Under Startup Suite click Contents… then Add…
  4. Navigate to the place where you installed sDNA (usually c:\Program Files (x86)\sDNA) and select the application sdna.vlx.
  5. Click Close on the Startup Suite dialog
  6. Click Close on the Load Application dialog
  7. In Autocad versions 2010 onwards, load the sDNA buttons:
    1. From the Ribbon, choose Manage → Custom User Interface (CUI)
    2. Locate the button for loading a Partial Customization File – the icon is a folder symbol with a green plus sign
    3. Navigate to the place where you installed sDNA (usually c:\Program Files (x86)\sDNA) and select sDNA.cuix
    4. Click OK
  8. Quit Autocad
  9. When Autocad is restarted, the sDNA application will be loaded.

sDNA for Autocad processes networks of polylines using the coincident endpoint connectivity rule (see network preparation chapter for more details on this). Networks using an intersection-is-connectivity rule can be converted using the sdnaconvertunlinks tool. This will take a mixture of polylines and polygons as input, and automatically breaks all polylines where they intersect (unless the intersection falls inside a polygon, which you can use to denote brunels).

After running sDNA Integral, you will need to use the sDNA Colour tool to display results.

In Autocad 2010 onwards, sDNA will appear as a series of buttons on the ribbon toolbar labelled “sDNA”. Simply click these buttons to load the tools.

In older versions of Autocad, it is necessary to know the commands for running sDNA. (These can also be used in Autocad 2010 onwards, if preferred). Enter one of the following at the command prompt:

  • sdnaconvertunlinks to convert from intersection-connectivity to coincident endpoint connectivity
  • sdnaloaditn to load ITN data
  • sdnaprepare to prepare the network
  • sdnaintegral to analyze the network
  • sdnacolor or sdnacolour to display the results of sdnaintegral

Advanced sDNA models in Autocad Map3d

To use the full data capabilities of sDNA from Autocad Map3d, we recommend the following workflow:

  1. Export data as a shapefile.
  2. Process in the free QGIS or by using sDNA from the command line.
  3. Re-import into Map3d.

This enables the use of Map3d’s sophisticated 3d editing and snapping features in sDNA models. However, please take note of the following:

  • Do not edit shapefiles as a Map3d mapping layer, as this discards 3d information.
  • Instead, create your network using Autocad polylines.
  • Models can be exported from Autocad polylines to shapefiles. Note that (1) it is necessary to manually specify export of all attached object data, (2) it is necessary to select the 3d export driver to preserve height data, and (3) care must be taken to preserve the spatial referencing.
  • Shapefiles can be imported into Map3d as Autocad objects, with data attached as object data, and preserving spatial reference.

Using sDNA from the command line

sDNA can also be used to process shapefiles from the command line. Before starting, you will need to install Python, if you don’t have it already. We have tested with versions 2.6 and 2.7; other versions may work as well. You can download Python 2.7.3 from here:

If your file associations are set up correctly for python (the python installer should have done this) and the sDNA bin directory (usually c:\program files\sdna\bin) has been added to your path (the sDNA installer should have done this), then you can use command line sDNA as follows.

The commands are sdnaprepare.py, sdnaintegral.py, sdnalearn.py and sdnapredict.py. Note that from the command line, various functions handled separately in QGIS and ArcGIS (geodesics, convex hulls, link measures, destination maps, network radii) are all handled by sdnaintegral.py. See Advanced configuration and command line options for more details; alternatively to learn the command for a given operation, try performing the operation from QGIS and see the command QGIS calls (shown in the algorithm dialog).

If you have ArcGIS 10.1 or later installed, then the command line interface to sDNA will also support work on geodatabase paths. Of course you can use sDNA from inside ArcGIS as well, but some of us like to make batch scripts to run outside of Arc.

Troubleshooting

If you haven’t, can’t or don’t want to set up file associations, then the instructions above won’t work. You will have to load python explicitly, e.g. (assuming python is on your system path):

python -u sdnaprepare.py --help

(or if it isn’t):

c:\path\to\python -u sdnaprepare.py --help

(or if neither python nor the sdna bin folder are on your path)

c:\path\to\python -u c:\path\to\sdna\bin\sdnaprepare.py –help

and so on, for the other sDNA commands detailed above.

Using sDNA through the Python interface

Those experienced in programming may want to use sDNA Prepare and sDNA Integral directly through our Python API. This is called sdnapy; the canonical example of its use can be found in runcalculation.py in the sDNA program folder.