[OSM-talk] 'Distance to feature' maps?

[Simon Wood]

On Tue, 14 Jul 2009 23:51:22 +0200
Frederik Ramm <frederik at remote.org> wrote:

> I happen to have a Perl script that does something like this

With some pretty simple mods (which even I could handle) your code can output a CSV list of lat/long/distance; however I struggled produce a decent contour from this.

Previously I had used a perl script to call Gnuplot to 'contour' the SRTM data, which worked fine. Using the data from your script had the problem that is was 'sparse' point data rather than an XY full table of data and as such Gnuplot didn't do a good job at creating contours.

There are 2 ways around this I can think of:
1) split the ways in the source data into many more nodes, so that there is more chance of Gnuplot seeing a line trend.

2) Play some math tricks to interpolate the output data, effectively performing the same thing.

Simon.