Read elevation from Swisstopo api for cross sections
Bas den Brok - mapping course

Understanding of python and maybe some understanding of SVG required.


We want to read the elevations between two given points in Swissgrid CH1903 coordinates to get the topography for a cross section between these two points. We write resulting elevations in a text file that can easily be imported in OpenOffice Calc and an svg-file to import the topography in Inkscape as an SVG polyline that can easily be converted into a path if desired.

In the below example of the pthon code we have chosen a cross section with point A (NW left) with Swissgrid coordinates (720000, 200000) and point B (SE right) with Swissgrid coordinates (730000, 190100) and set the number of intervals N=50. The length of the cross sections, i.e. distance betwen A and B equals L (in meter) and the distance between the 50 points that will make up the topography euqals n (in meter).

We open two files to write data to: one text file and one SVG-file.

Output on the screen looks like below. The numbers 50, 6, 83, 18, 10, 24 etc. indicate the numbers of characters written to the SVG-file

Below is an example of the text file for in OpenOfficeCalc showing for each point on the topography line the two Swissgrid coordinates, the distance from point A and the elevation (in meter).

Here below is the code of the SVG-file with the polyline representing the topography between A and B.

and how it looks in Inkscape.

And finally here below the text file in OpenOfficeCalc.