I’m doing some digitizing for a project in the office, basically I’m plotting the entire road network in a city environment.   This sounds easy doesn’t it? Just plot the thick black lines and you’re done.   Well this is a country with a hot desert environment and a poor quality road network.   To compound matters there is a high water table, and places where there is no underground sewer network.

satellite image of informal road network
Informal Road Networks - but how do you record them?

The upshot of this is there are many informal road networks, even in the ‘developed’ neighbourhoods.   It’s quite easy sometimes to make a good guess as to the line of a road based on the housing.  But the road accessing a particular development can be erratic taking account of features and circumstances I cannot see from my satellite image (soft sand for instance).   What’s more how am I to know that this is a permanent road?   Sure it looks fairly set now but come the next season it will all change.

My general approach is to first establish what kind of project I’m working on and what information is required for the job.   Here I am choosing to acknowledge the existence of these informal tracks, especially the ones that look heavily used.   I’m also ensuring that the lines I’m creating have appropriate information about the feature for instance: “informal, access, unmade”.  I’ll also add some meta data to ensure anyone in the future who finds my work knows what satellite image I digitized from and what date I plotted it and for what purpose.

So fellow GIS professionals (particularly the ones that like to digitize) how do you digitize yours?  I’d really appreciate your insight if you could leave a comment or dm me on twitter that would be great!


  1. Satellite imagery is probably the best option or digitising from the above description. In terms of attributes you may want to consider options like paved, un-paved, poor condition (paved), major road, minor road etc.


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