[Gdal-dev] GDAL 1.19 with ECW problems

[Mark Cave-Ayland]

Hi everyone,

I've just downloaded the latest release of OpenEV from Sourceforge with
a view to seeing how well it can cope with ECW files. Unfortunately I
discovered that with the default Windows installation, no ECW support is
included, so I downloaded the ECW SDK along with GDAL 1.19 from
remotesensing.org and recompiled with ECW support under VS6 using the
instructions on www.remotesensing.org.

The installation process went something like this:

1) Point ECWDIR to C:\Program Files\Earth Resource Mapping\Image Web
Server\Client
2) Copy NCSECWc.dll from C:\Program Files\Earth Resource Mapping\ECW SDK
to the above directory (it appears to be a very old version but I don't
want to compress files yet anyway so this shouldn't matter).
3) Add the following lines near the top of ecwdataset.cpp:

CPL_C_START
void GDALRegister_ECW();
CPL_C_END

4) Compile GDAL installing into C:\gdalinst
5) Check gdalinfo --formats to make sure ECW is listed.
6) Make a copy of gdal11.dll as gdal119.dll
7) Add the following to INCLUDE_DIRS in setup.py - "C:\gdalinst\install"
8) From the OpenEV installation of Python launch the following:
	python setup.py install
8) Copy gdal11.dll to OpenEV\bin
9) Copy _gdal.pyd as _gdal.dll into OpenEV\pymod

After this fiddling (I've only ever used Python once before!) I managed
to install my new copy of GDAL in the OpenEV directory and I can now
load an ECW into OpenEV using File->Import and I've managed to export an
ECW as a JPEG. So far so good.

The part I'm now struggling with is trying to create a 3D view using two
ECW rasters - a standard and a DEM. Unfortunately the problem I'm
finding is that if I go to File->Open or File->Open 3D to load in the
ECW file then Python generates an exception and crashes :(. So I guess
what I'm looking for is: i) does this installation sound about right or
have I really messed up my OpenEV installation, ii) why is File->Open
different from File->Import and iii) how can a Python newbie go about
debugging a GDAL/Python application under Win32 to find out exactly what
the problem is?


Many thanks,

Mark.

---

Mark Cave-Ayland
Webbased Ltd.
Tamar Science Park
Derriford
Plymouth
PL6 8BX
England

Tel: +44 (0)1752 764445
Fax: +44 (0)1752 764446


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