Hi, i create my maps in 2 steps: first: I create all osm-tiles from download.geofabrik as OSM. img-tile (containing 1-Sec DEM) and Contourlines from different soures as Contourline. img-tile. This works good, no problems. Second: I combine the ready OSM.img tiles and contourline.img tiles to the mapset. I use command : java -jar mkgmap.jar -family-id=3100 -route ..... -dem=\\HGT\1SecHGT\ -overview-levels=5:15,6:15 *-overview-dem-dist=*110000 -gmapi \500*.img \400*.img . The resulting TestKarte.gmap seems to bee good in Mapsource and Basecamp. 3D-VIEW works. *But really the tdb and preview-files are corrupt. Especially the preview contains wrong 0x4a and 0x4b. The borders of contourline.img should bee always 1°x1° degree. But the are always smaller. The osm-tiles has wrong borders too. It looks for me, as if the borders are randomly. This prevent Mapsource and Mapinstall to send tiles to the GPS, respektivly the sended tiles are to small at GPS. *I maked a little investigation and found out, that the option *-overview-dem-dist=110000 *causes the error. Without this option all works fine. But the preview has no DEM. I am not a java coder and can not find out, what goes wrong. Maybee the spezialists can find out it. Here is my test-equipment : 2 osm.img (500*), 2 Contourline.img (400*) . as source and the resulting TestKarte. gmap as Test.rar Download : https://d100635.odilo.greatnet.de//data/public/75d14fa5dd1b9abbb7acf7af8b3c1... The HGTs are N46E011.hgt and N46E012.hgt. Screenshot Mapsource : http:\\img2ms.de\Bilder\Wrong0x4a.jpg Thanks Thomas