Hi Gerd and Henning, > If accuracy of srtm is +- 10m and the difference between > with/without interpolation is +-1m, then it's definitely not worth > spending any effort on interpolation.
This is not like interpolations error is placed within source data error. This error is added to data error. I believe it can be much bigger, especially in case of 3" HGT. This could be tested.
Apart of height error, there is a problem of DEM shape. I mean the exact places where is a peak of a mountain or heights points in a profile of a route. With simple interpolation, there probably would be much bigger positional error.
I have read reports, that increasing DEM resolution above HGT resolution increases DEM quality. But this was opinion about bilinear interpolation, maybe there is no need for such a settings with better interpolation?
-- Best regards, Andrzej _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev