Rough edges on tiles in QGIS

Question

I'm loading four .ASC files into QGIS, each containing topographical data about a tile of 10 x 10 km. On the map, this data is displayed as black/white and different shades of gray. My problem is that the edges of each tile are very clear where the four tiles meet. Is there any way to get QGIS to polish this up, so as to achieve a smooth transition?

Answer 1

You get this kind of picture because every file has a different range of gray values, and QGIS scales the colours between min and max seperately. To solve this:

• Create a virtual raster on all your files using GDAL, or from the QGIS menue.
• Load that instead of the individual files as one single layer.