Hi all, I am not aware of any erros in r4091, so I think it is time to merge it into trunk. I see only one problem: HGT data changes rarely, so I'd prefer to do the costly DEM calculations only once and be able to store the results. I've already described how to do this here [1] but I'd prefer to have a container format that allows mkgmap to extract the Garmin DEM bitstream data for a given lat/lon pair from a file. Such a container could contain the DEM data for one or more dem-dist values. It could be empty first and grow each time you calculate DEM for a new area. In subsequent executions of mkgmap it would check if the container already contains the data for the wanted area. Advantage would be a faster tile compilation and less power consumption, disadvantage would be the additional disk space and higher complexity. [1] http://gis.19327.n8.nabble.com/Performance-with-zipped-hgt-files-tp5909756p5... Gerd