|Version 6 (modified by 12 years ago) ( diff ),|
Download ECW JPEG SDK
In order to use ECW format with GDAL, you need to download Image Compression SDK from ER Mapper website. The SDK is available to download for logged in users on the website, so first you will need to register.
Building libecwj library on Unix
In order to use GDAL with ECW support under Linux, Solaris or Mac OS systems, you will need to build the libecwj library on your own, so it's required to download Image Compression SDK Source Code but not the binary distribution which is dedicated for Windows family systems. Current version is ECW SDK 3.3 and the source code package is named libecwj2-3.3-2006-09-06.zip.
The source code is equipped with configure and Makefile.in scripts. There is also an utility script called bootstrap that can be used to regenerate the configure and Makefile.in files, if you have installed required tools: autoconf, automake, m4, libtool.
In the former case, the procedure is simple:
$ cd /path/to/libecwj2-3.3 $ ./configure $ make # make install
where the last step should be run as superuser.
By default, the libecwj is installed using installation prefix pointing to /usr/local. You can change this location with --prefix option of configure script. Run ./configure --help for more details.
Mac OS X notes
There are a few problems possible with libecwj2-3.3 on Mac OS X. For more details, refer to Ticket #2032 - Building with ECW support on Mac OS X
Building GDAL with ECW support on Unix
Assuming you've installed libecwj library under default location, procedure of adding ECW support to GDAL is simple and you only need to provide GDAL configure with path to the ECW SDK installation prefix:
$ cd /path/to/gdal $ ./configure --with-ecw=/usr/local $ make # make install
After these steps, you should be able to see the ECW in the list of formats supported by your GDAL installation:
$ gdalinfo --formats|grep ECW ECW (rw): ERMapper Compressed Wavelets JP2ECW (rw+): ERMapper JPEG2000
Building GDAL with ECW support on Windows
TO BE DONE
Building libecwj2-3.3 from source using recent compilers may require some improvements that can be found in the ticket #3162 - Fixes and patches for libecwj2.
A problem with opening and closing many ECW files consuming large amounts of memory with libecwj2-3.3 may be resolved using the libecwj patch in http://trac.osgeo.org/mapserver/ticket/3245.
A patch to avoid overflow in Linux implementation of NCSPhysicalMemorySize() in libecwj2-3.3 is available in the ticket #3366. This work around big memory usage for computers with RAM > 2 GB.