Saturday, December 22, 2007
I am still studying for my Australian Citizenship Test. Paul if you are so eager you can do this one here, it has answers unlike mine where I am too mean to provide answers. Only the question about which is the political party currently in power needs the answer to be revised since Kevin Andrews is no longer holding down that particular plum job. All hail the separation of power now that the Federal Court has reinstated the Haneef visa. I hope they have a question about how arms of the government tangle with each other.
Also test drove RAT TerraSAR-X Driver and INSAR capability, it was a breeze producing unwrapped phase. Just need to quantify the baseline and extension to spaceborne platform position information to allow accurate DEM generation.
Tuesday, December 18, 2007
From the OTB 2.0.0 Release announcement:
A major release like this one happens once a year. The OTB Development
Team has worked very hard in order to make available a robust library
with plenty of very interesting things. Thanks to Emmanuel, Thomas,
Julien, Romain and Cyrille for the good work.
Be careful: with OTB-2.0 you can build powerful applications easily and
for free. You can for instance produce a pan-sharpenned, ortho-rectified
Quickbird image in a few lines of code. This can hurt sensitive people.
Other key features include:- Radiometric calibration using the 6S radiative transfer code. - Image registration with parametric geometric transformations. - Demo applications for change detection, road extraction, visualization, etc. - All existing features of version 1.6: segmentation, classification, feature extraction, spatial reasoning, change detection, etc.
OTB tends to lean towards being monolithic at times with internal source tree copies of ITK, Boost and Ossim, but it keeps people away from having to separately download and install dependencies. The only external things to install are CMake - it makes multi-platform builds a breeze, a pre-built binary copy of GDAL from FWTools and FLTK, a simple GUI toolkit which trades speed for aesthetics. Personally I would prefer a nicer GUI Toolkit such as Qt but FLTK works just fine, and the whole approach is library oriented so it will be easy to plug-in your own GUI.
After a few false starts I built OTB with MSVC++ Express and NMake files from CMake. Here are the basic screenshots.
Basic Viewer Manager:
Diaporama (ENVI Style viewer with transitions):
Interactive Change Detection:
Sunday, December 16, 2007
Saturday, December 15, 2007
First open a suitable mapset in Grass from QGIS (follow the QGIS-Grass tutorial) and connect the mapset to an sqlite database by choosing sqlite driver from the dropdown box as shown below. Edit the database location so the it is created in a directory that exists, I suggest removing the already suggested dbf folder(meant for the dbf driver) and replacing it with sqlite.db. In the future this should be auto-suggested by QGIS.
Then open a suitable Shapefile or other OGR supported vector format for import into Grass. Your screen will look something like below.
Now import this dataset into Grass using the Import Vector from OGR command as shown below. You can also use the Grass shell to ensure that your attribute table gets created in the Sqlite database. After this step your vector is ready for use in Grass and all the attributes can be manipulated using SQL in the Sqlite database to perform joins with other tables or any other operation you can dream up.
The final map with various classifications produced from the Brazil dataset after importing it into Grass is shown here.
Friday, December 14, 2007
- Don't trust libtool - Libtool in MingW is rather hobbled and needs to be fixed for long link lines using a the sed command described here.
- Use -no-undefined - MingW linker does not like linking to libraries with some undefined symbols, use that linker flag when compiling dependencies.
- Create shared libraries not static ones for dependencies.
- Learn you way around the reverse engineering tools for porting from MSVC built static and dynamic libraries, specifically reimp, pexports and dlltool. Sometimes function call definitions need to be renamed using sed or added with @4 or @32 at the end (not sure what purpose this serves), I picked it up while building MySQL libraries for linking.
- Edit any autoconf or pkgconfig scripts to use MSYS style include and libs location(Those nasty slashes will get you otherwise).
- Any of these tricks may fail if you have specific name mangling, assembly code and other fancy things in the MSVC libraries. I have still not managed to make a linkable version of libecwj2.dll (ErMapper - Leica ECW/JPEG2000 library), mainly because it contains some of the above features.
Wednesday, December 12, 2007
The Gold Qgis release build with grass compiled with ODBC, Sqlite, MySQL and PostgreSQL. I could not get GDAL linked with the same MingW being second class citizen in the GDAL world and libtool being annoying and limited as always. The current one is available here. Hope it works for you. May be one day we will have a Platinum release.
ImageLinker , the Ossim image processing GUI is now nearly fully ported to Qt4 and builds and runs fine if you do not try to optimize too much and strip symbols.
Sunday, December 9, 2007
Qgis releases seem to be coming along fine. Now even my photo is in the official developers list. What an honour !!
The windows installer is available here for testing till an official release is announced. It includes latest grass release candidate, but misses Xerces and hence GML support. Living on the edge has cost me, GDAL Xerces detection to longer picks up my Xerces and Expat. I hope this will be resolved by the time we make a full release. I will try rolling back GDAL until it works but this is the latest of the latest code based release.
Thursday, December 6, 2007
Sunday, December 2, 2007
I am back in Adelaide in space , but not it time. My body clock is all messed up and keeping me awake at night. At least it is some other time of the day somewhere else so I can be productive. Qgis seems to making great progress towards a full MSVC build, that may not sound so good to Open Source purists, but on Windows MSVC offers superior compile time and debug capabilities than MingW does at the moment.
Tim has put together a short-cut bundle of binary dependencies so that you do not have to build everything (but building stuff is my favourite passtime anyway). The build works fine without Python-SIP, which will be easy to add and GRASS which will be slightly messier to add.