Hi John and Axel

(First of all, sorry if this message appears duplicated, I sent it on
Friday, but I got a "rejected" message, so I'm trying again today using
plain text format.)

John , the VRT you have generated lacks the CRS information, but looking at
the corner numbers, it looks like it could be EPSG:2391 (NZGD2000 / New
Zealand Transverse Mercator 2000).
Of course this is a guess, I'm not sure on this.

As Axel has pointed out, the next step is to check if each source tiff file
is georeferenced. This can be done at the command line:

gdalinfo /home/sdc4/GeoMaps/Featherston_BP33_GeoTifv1-08.tif

and so on.

If all source files are georeferenced, the VRT is expected to be created
without problems. (take in mind that all source files must have the same
CRS).

Anyway, you can manually declare a CRS for the resulting VRT by adding the
-a_srs option to the gdalbuildvrt command. (Normally it is not necessary to
use the gdalwarp command). example:

gdalbuildvrt -a_srs EPSG:2391 Map.vrt georefmap1.tif georefmap2.tif
georefmap3.tif

The above is for the command line, but you can also do it in QMS with the
"Build VRT" tool.  In the VRT builder dialogue, to manually declare the CRS
you should check the "Advanced options", and fill in the -a_srs box by
typing EPSG:2391 (or whatever you need).

*** Be careful... when you click on "advanced options" you run the risk of
becoming an advanced user ;-) Or at least you are on it !
Try it and let us know

HTH

mitxel

El mié, 21 abr 2021 a las 10:17, John Groombridge (<[email protected]>)
escribió:

>
> I am trying to activate a vrt map in QMapshack that I created using:
>
> gdalbuildvrt  Map.vrt  georefmap1.tif   georefmap2.tif   georefmap3.tif
>
> georefmap being geotiff maps.  But when I try to activate the map in QMS
> it fails with "No georeference information found."
>
> QGIS opens the Map.vrt ok.  What am I missing??
>
>
> Kia ora
>
> *JohnG*
>
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