Comments on: GSoC 09 Weekly Report #4: 12/06 – 19/06

By: jorgearevalo

jorgearevalo — Mon, 29 Jun 2009 01:51:25 +0000

Thanks for the info Even!

By: Even Rouault

Even Rouault — Sun, 28 Jun 2009 22:09:52 +0000

The sibling list is just a list of files in the same directory of the file to be GDALOpen’ed. This was an attempt to improve performance for file-based drivers that need to read auxiliary info in files next to the main file (for example a .tfw file for a TIFF file). See http://trac.osgeo.org/gdal/wiki/rfc11_fastidentify. (I’d note that it can actually decrease performance when there’s a huge number of files in the directory). The sibling list may be safely NULL and in your use case, you don’t have to care at all about it since you’re developing a server based driver . You just need poOpenInfo->pszFilename and perhaps the poOpenInfo->eAccess flag if you want to distinguish read-only/read-write

CPL/VSI functions : some of them are documented at http://gdal.org/files.html.

I’ve looked a bit at your repository. One stylistic remark : avoid using tabulation character. Use spaces instead. In WKTRasterDataset::GetGeoTransform(), you can remove the code for if (padfTransform == NULL) : it’s illegal to call GetGeoTransform() with padfTransform == NULL and your code would crash anyway
In

By: Mateusz Loskot

Mateusz Loskot — Thu, 25 Jun 2009 10:01:52 +0000

I never do “make install” when I want to test and debug GDAL or GDAL-based programs.
Just configure your environment the way GDAL library can be found by your program.

Here are my configuration scripts I use:

http://mateusz.loskot.net/tmp/gdal/gdal.source
http://mateusz.loskot.net/tmp/gdal/config.sh

By: jorgearevalo

jorgearevalo — Thu, 25 Jun 2009 01:22:58 +0000

Hello Mateusz,

I answer your comments

1. Ok. I try to spell always in the way you like, but I’ll correct the errors. I’m sorry for this.

2. Oh, it was a minor doubt. I was trying to understand what kind of information has a GDALOpenInfo object, and when it’s created, and I read the concept “sibling list” in this file http://trac.osgeo.org/gdal/browser/trunk/gdal/gcore/gdalopeninfo.cpp (line 127). But I think it’s not really important now.

3. I checked that page to create my ignore list, actually. Many thanks for the link, anyway

4. Maybe it’s not clear. I checked out PostGIS and GEOS from SVN. Then, I compiled them and installed them. I did the same with the WKT Raster extension, of course. When I said “I only compile the WKTRaster code” I was talking about GDAL WKT Raster driver’s code. And this is a doubt: I can do ./configure – make – make install with GDAL sources every time that I make a change (in my driver’s code). But I can simply re-build the driver’s code with each change, not the whole GDAL library. Is correct?

I’m very interesting in your post, I’ll keep an eye on your blog

Thanks for your comments!

By: Mateusz Loskot

Mateusz Loskot — Wed, 24 Jun 2009 09:29:59 +0000

Jorge,

A couple of comments:

1. The spelling of PostGIS is PostGIS not Postgis, PostgreSQL not Postgresql, also it’s “WKT Raster” but not “WKT raster”. It’s fairly important.

2. What sibling list you mean? Link it to specific place in GDAL/OGR code from Trac source browser and it will be easier to find out.

3. Check this for svn:ignore (http://svnbook.red-bean.com/en/1.1/ch07s02.html#svn-ch-7-sect-2.3.3)

4. What you mean as “I only compile the WKTRaster code”?
The WKT Raster has one direct dependency (PostGIS) and one indirect (GEOS). The WKT Raster requires very recent version of PostGIS (I suggest to grap source from its SVN trunk) and that recent version of PostGIS requires very recent version of GEOS (again, GEOS from SVN trunk). I build, run tests and install both of them every morning without problems – it’s easy.

I am going to put a post about WKT Raster installation, hopefully tonight.
Feel free to ask if you have any questions.