What is a DEM (Digital Elevation Model

[eslam mamdouh]

شكرا على مرورك الكريم ووفقك الله

[احمد حسن]

thank you ESLAM MAMDOUH for this great information
but a wonderd

why the companies _ as you say _ hide there data if it allready found in the land grid and we get and create a huge numbers of mackets or model that help us to use this area easly