[GIS] ECW not reocgnized as supported file format in GDAL operation

ecwerdas-imaginegdalqgisraster

I've installed QGIS 3.6 for MAC, with GDAL 2.4, ECW GDAL Plugin for GDAL 2.4, and manually installed the libraries from ERDAS ECWJP2SDK 5.4.

This allows me to insert ECW files as raster layers in QGIS. I'd like to export them all as GeoTIF, so I was thinking of using GDAL Translate (convert format) in batch mode.

However, GDAL doesnt seem to recognize ECW: in QGIS messages panel I get "xyz.ecw not recognized as a supported file format.".

In QGIS preferences / GDAL I am seeing ECW with "rw+" flag and "ERDAS Compressed Wavelets (SDK 5.4)" so I think it was installed correctly (and ECW files do display, they just are not understood by GDAL).

All help deeply aprecciated.

Using macOS 10.14.3.

Best Answer

I got it to work. I think the instructions on the QGIS 2.6 for macOS installer's read me are not 100% correct. There we can read:

For the Value enter: /Library/Frameworks/Python.framework/Versions/3.6/bin:/Library/Frameworks/GDAL.framework/Versions/2.3/Programs:

but it turned out I had to enter 2 PATH variables and not only one. Plus, the GDAL version should be 2.4 instead of 2.3!

Do it like in the image above and GDAL will recognize ECW files.

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[GIS] GDAL does ECW but QGIS (Linux !!) does not load ECW file

Sorry for late reply, had to get time free to sort it out from a brand new setup. Found out what is causing it and it has nothing to do with using the correct gdal as suggested in Answer 1 (I did run into it before as automatic updates on linux will happily upgrade the qgis-installed GDAL to 1.9.1-2~precise4 and you get that version-mismatch error).

A fresh install of QGIS 1.8.0 on a new linux mint 13 (ubuntu 12.04 precise) installs GDAL 1.7.3-6ububtu3 and that is the one against which the ECW support gets compiled. I did exactly the same as listed in my original post, and as expected the qgis-installed gdal 1.7 does support ECW while QGIS does not. Back to square one...

However, in the course of digging through tons of website pages, I did come across a post somewhere (lost which one, though) that mentions that from gdal 1.8 the location of the pluginsdirectory has changed from gdalXXplugins to gdalplugins/1.8. As QGIS 1.8.0 actually uses GDAL 1.7.3-6ubuntu3 under the hood I had ignored that info. Unfortunately, this information is not correct!! GDAL 1.7.3 also needs to have the plugin stored in the gdalplugins/1.7 folder! This is not done by the scripts so you have to do it manually. I did it by using prefixes on my last install, but it is as easy to just create the /usr/lib/gdalplugins/1.7 folder by hand and copy/move the so file from the /usr/lib/gdal17plugins folder. Done. Now QGIS 1.8.0 finds the plugin and loads ECW fine.

Hope this helps others in the same situation. Not to mention the fact that one must find the correct gdal ecw source! The 1.7.2 source is only found when you edit the repo by hand to use the old "hardy" version. If only qgis.org could keep that one file in its repo too... Sigh. Lewie

[GIS] gdal python set projection of a raster not working

In the first script, you should use srs.ImportFromEPSG rather than srs.SetProjection.

i.e.

srs = osr.SpatialReference()
srs.ImportFromEPSG(27700)

...

ds.SetProjection(srs.ExportToWkt())

It is hard to tell where the second script is going wrong without access to the reference image you are using.

Best Answer

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[GIS] GDAL does ECW but QGIS (Linux !!) does not load ECW file

[GIS] gdal python set projection of a raster not working

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