[SoC] - Ossimplanet integration with Grass and Qgis - status report #1

[massimo di stefano]

Hi All,

  i'm Massimo Di Stefano, working on the Ossimplanet integration with  
Grass and Qgis.

here for my first report, a description about the project, its  
timeline etc .. is on

my wiky page for the project is hosted here:

http://trac.osgeo.org/ossim/wiki/GoogleSummerOfCode

The code is under svn you can browse it here :

http://svn.osgeo.org/ossim/trunk/gsoc/

I'll store the summary reports for each week here :

http://trac.osgeo.org/ossim/wiki/WeekReport?action=edit


-- Report --

i start to wrote code  .... my first time using svn (cool!)

i'll try to describe it here ...



what is done :

-  code to use ossim TCP capabilities to set a position and a point of  
view based on (lon, lat, altitude, roll, pitch, gain) (finished)
-  code for reading the gps data from dgps and display the nmeadata in  
the gui (include a map view using qtwebkit), it will use a fixed  
position (gps) and a modificable view setting (roll,pitch,gain)  
(finished)
-  code to change the position using a joystic (needs some  
implementation yet, but is ready for test)

so the position message can be sended using gui, gps, joystick

- code to read the grass environment and retrieve a list for vector,  
raster and regions in the running mapset
  so it is possible to syncronize the posiotion in ossimplanet on the  
center of the active grass region or change the region to a speciphic  
layer or saved region

- code to export grass elevation data to ossimplanet (g.ossim) the  
code is usable from the pyqt gui or directly from grass (finished)
- code to read vector layer in grass and export it to kml (it is to  
have a custom kml settings, like color, label etc...) (needs testing,  
not finished)


next steps :

- finish the code i described first
- initial work on a table widjet (it will contain the avayable layer  
in the mapset and a checkbox for each layer i'll try to realize a  
"query system" connected to the gui )
- reorganize the code in a clean way, ranaming function give them a  
better position in the code and create comment
- starts a depth immersion in the ossim-gdal code


known problems that can block me :

using the gdal-ossim plug-in we can read grass raster layer but there  
are problems to reneder images with more than 255 entries in the  
colortable.

i had a chat with FrankW where we discuss a bit the problem, i stored  
the irc log here :

http://trac.osgeo.org/ossim/attachment/wiki/GdalOssimPlugin/frankw_irclog.txt

tring to summarize it :

the code needs to be modified to handle three cases - 8bit, 16bit and  
32bit integers and to error out gracefully if it isn't one of those  
cases...
... and "the s[sample] value it fetched from the input buffer this  
would need to be altered to fetch it based on the type of the buffer."  
in function loadIndexTo3BandTile

what i learn .. :

theSingleBandTile    --->  point to a byte array (that isn't every true)
theGdalBuffer.resize(theSingleBandTile->getSizePerBandInBytes()*2);   
---> the band is readed correctly but is is "casted" to 8bit

i think gdal-grass should read correctly the grass data, so maybe the  
problem is in the colortable rendering in the GDAL OSSIM driver.

i'm tring to documenting myself reading :

http://www.gdal.org/gdal_datamodel.html

and :

ossimGdalTileSource::loadIndexTo3BandTile()

... seems it accepts only raster files with 3band or with indexcolor ,  
need i a function to port in rgb mode a grass color table ?

i'm reading the grass colortable structure to learn more

any suggestion, lines of code, examples ... that can help me to know  
how to work on the gdal-ossim code ..  can make me happy
... i know it is not a simple task.


thanks to Osgeo, All the Dev-Team and Google for this cool experience!







Massimo Di Stefano
massimodisasha at yahoo.it

epifanio on   irc.freenode.net  /join gfoss














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