I've been importing raster files in ZMAP format using QGIS 2.4 and 2.6. Some of the files work fine but other files for some reason import a black image with nan as a default black and white value. Applying actual min and max values does nothing and shows the values in the raster file as zero.

The ZMAP files have all been exported equally from a gridding package, i.e. same XY min/max, header files look much the same, there are sensible values in all files, etc.

Any suggestions as to what might be causing this?

1 Answer 1


I resolved the issue by importing all my ZMAP files into another piece of software (Petrosys) and re-exporting them as ZMAP files. All the files now load correctly into QGIS 2.4.

I'm not sure if this is an export issue from the original software (formats between files appeared identical) or a QGIS import bug?

Either way Ive' found a workaround.


  • We faced some similar problems, but not during import, but after processing the raster in QGIS. In our case, the meta data of the file was somehow crippled. Would be interesting to see a comparison of the non-functional and the working file. You can see the meta data through Raster -> Miscellaneous -> Information. In our case the, the info about the min max data was missing, so QGIS could not display it correctly, nor was there a way to restore the meta data.
    – Bernd V.
    Dec 9, 2014 at 10:54

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