Following this question, I've tried to use interpolation in QGIS to get a sense of the topography of a map based on about 3500 track points with elevation. The elevation ranges between 213 and 353 meters with a 312 meters average.
I then try to use IDW with the following parameters:
It takes a few moment to process and then I get a raster with absolutely no variation. The max is the average value and I've got a min of NaN. Of course, the rendering is all of the same color since there is no variance.
By asking for an ASC file instead of a TIF, I can confirm that it looks like it's creating a grid with the same value (average elevation) all over..
What am I doing wrong?