We’ve been saying for years that we should provide more support for transparancy, reproducibility and accessibility of research with an open source release of sDNA, so here it is at last: sDNA Open released under GPL3 on Github. Hooray!

That said, if you’re not reading or editing source code, we’d prefer you to continue to download sDNA from this website. Right now, the functionality of each version is the same, and if you stay here then

1. we can continue to monitor how many people actively use sDNA (rather than just download it), which makes it easier to demonstrate its value to sDNA funding councils, who might fund further developments which benefit you, the users.
2. if you sometimes use sDNA+, it’s just one installation for both sDNA and sDNA+ so you can switch back and forth easily.
3. you can also stay in touch on our mailing list, which provides updates on sDNA and related research about once per year.

Happy network analysing.

It’s time to announce sDNA version 4, or “sDN4″…

For funding we are thankful to Wedderburn Transport Planning, and also Alain Chiaradia and Chris Webster for re-investing their royalties from sDNA+.

sDN4 includes several new features, principally the ability to weight analysis by zones as well as the existing options of links, length and custom weights. All of the above can be combined using custom expressions, and weights from zones easily distributed over each zone according to user defined functions. This is well suited to conducting high resolution sustainable transport analysis based on low resolution census data.

In addition, numerous features previously restricted to those who purchased sDNA+ licenses, have now been moved into standard sDNA:

• Outputs
  • Skim matrix
  • Geodesics
  • Hulls
  • Network radius
  • Destination maps
  • Bidirectional betweenness
  • Flow bundles (use intermediate link filter for these)
• Other features
  • Origin Destination (OD) matrix input
  • Banded radii – useful for multivariate analysis with a little less collinearity
  • One way links
  • Custom spatial tolerances
  • sDNA prepare preserving data
  • Selected origin/destination and skip functions
  • Link disabling functions
  • Advanced problem route handling
  • Oversampling

sDNA 4 is available on the usual download page.

Crispin has been involved in a large cycling collaboration led by Bendik Manum of Norwegian University of Science and Technology Trondheim, and also including Chalmers University of Technology Sweden and our own collaboration with Arup Cardiff.

The results will be presented at 12^th International Space Syntax Symposium, Beijing, 8^thJuly.

Bendik Manum; Tobias Nordstöm; Petter Arnesen; Crispin Cooper; Jorge Gil; Erlend Dahl; Ringo Chan; Lillian Rokseth; Sylvia Green: “Using realistic travel-time threshold in accessibility measures of bicycle route networks”.