Download of very detailed DEM files for Portugal?

Question

Operating system: Windows 10, 64 bit. QGIS Version: 2.13.3 which I installed via the QGIS.org website.

I need contour lines for a small area in Portugal.

I saw a guide posted here: http://planet.qgis.org/planet/tag/contours/ which explains how to get some very detailed contour lines using a DEM raster image.

I have tried to search for DEM raster images but they all seem to not have the correct detail level and I end up with very straight contours.

Can any of you point me towards a place for downloading (if possible) free DEM raster images in a 1m x 1m grid?

Answer 1

A 1m x 1m grid might be a lot to ask for. Even in places where I have found such DEM, the coverage has been spotty at best. Also keep in mind that if you are converting the DEM to contour lines, having such a small grid size may not matter unless the DEM picks up large changes in elevation between two cells. For example, if you convert to 1m contour lines but it takes the DEM 5 cells to change 1m in elevation there would be little difference between a 5x5 and a 1x1 DEM. Now onto a source for DEM data. In the past I did some research into possible elevation layers in Western Europe. The only source I came up with was a data explorer that can be found at https://search.earthdata.nasa.gov/search/project. You will need a log in but it is free to register. Hope this helps.