lig fietser has shared a OneDrive file with you. To view it, click the link below. <https://1drv.ms/u/s!ApArbaVZkx5rbZCEfL0GVPRjSz8> [https://r1.res.office365.com/owa/prem/images/dc-jpg_20.png]<https://1drv.ms/u/s!ApArbaVZkx5rbZCEfL0GVPRjSz8> atlantic_DEM.jpg<https://1drv.ms/u/s!ApArbaVZkx5rbZCEfL0GVPRjSz8> Hi Frank, I was running your tool on my Atlantic map and got a system out of memory error. The script did continue to build the dem data but in my map a few islands in the center of the map were missing DEM data (see the red area in the attachment, Sao Miguel on the Azores and La Palma and El Hierro on the Canary Islands). Any idea how to solve this issue? The map OFM_Atlantic(13-10-2017_gmap you can download at http://www.openfietsmap.nl/downloads/atlantic DEM tiles I downloaded from http://www.javawa.nl/srtm/index.php?lang=en (viewfinder panoramas) <http://ftp.nluug.nl/pub/maps/openfietsmap/Atlantic/OFM_Atlantic(13-10-2017_gmap).zip> The command that I used is: for /D %%i in (34351*.*) do (BuildDEMFile.exe -d %%i\%%i.DEM --hgtpath=%hgtpath% --tre=%%i\%%i.TRE --lastcolstd --usedummydata --dlon=0.00027761 )