I am new to QGIS (former Arc user) and having trouble with the raster merge tool.
I am merging 7 tiles of SRTM arc 1 data to cover a province in eastern Ecuador. Data is resulting in large areas of total black areas. I've done quite a bit of research on GIS stack exchange to troubleshoot: - I've made sure my output data type is consisent with input (int16) - I've tried merging with both projected and unprojected data - I've tried some general tinkering around with the style settings on each DEM - I've tried the tool in both QGIS 2.18 and 3.0
At this point, I'm fairly positive it has to do with the large variations in my minimum and maximum values in each tile -- I am working with an area that goes from high elevation of the Sierra mountain range down into the Amazon basin, so my real range is between 127 and 6218. My output comes out 0-6218, which is close enough to the real range (127-6218) that adjustment of the min/max of the output DEM to reflect real range doesn't do much. Extremely changing the min/max values in the final output DEM allows me to see data where there is black, but simultaneously "erases" data at the other end of the spectrum (If the high elevation data appears, the low elevation data disappears, and vice versa).
I do not see any parameter to adjust in the merge tool to fix this. Anyone have any ideas?? Below are some screenshots of original data, merge parameters, and output in order: