Another thing to look at while I’m at it: DMSP data

18 07 2008

Urban areas are likely to emit more artificial light, right? Well thats the idea behind this side-project anyway. The Defense Meteorological Satellite Program (DMSP) monitors meteorological, oceanographic, and solar-terrestrial physics for the United States Department of Defense and I’ve found this pretty cool high-res (8mb) image of the World at night on Wikipedia. If I can obtain some even higher resolution images like the LandSat data then I’m sure I could do some nice analysis as with the LandSat data, to predict where we should have more information in OpenStreetMap. So this is almost a plea, if you  find any more detailed data then please let me know!

New project: Lets use LandSat

10 07 2008

Not sure about the licensing requirements for my beautiful Qgis model (which shows roughly which areas of the UK are complete and which incomplete) so I don’t think I can publish the full results from that yet. Essentially though I have found that there is a strong correlation between the length of road in a particular area and the population in that area, its good enough to accurately predict the length of road there should be in an area and compare that to OSM road length. But enough about that project for now, hopefully soon I will publish all my findings.

So instead its onwards and upwards to a new project which was inspired by the view of the Osmarender layer on OpenStreetMap, shown below. It is clear to see that there are vast areas in Asia and South America, where there is no OpenStreetMap data, the question is whether there is actually nothing there or OSM is just missing cities, roads etc. I plan to find out using open source aerial imagery.

The plan is to use LandSat and other forms of freey available imagery to work out where there should be cities and roads and where there shouldn’t be. Then take this information and compare to OSM. Easier said than done, I’m sure but it wouldn’t be a project if it wasn’t challenging. So below is a LandSat image of London and to the North, which I have applied a Yellow Contrast Gradient Map to, using GIMP. As you can see it emphases cities and rural areas quite well and I’m sure this is the starting point to predicting accurately where there should be OSM data.