[GRASS5] new vector2

[Radim Blazek]

Hi again,

sorry but my last mail was somehow destroyed on the way, here should be full text:


i would like to discuss some problems related to new vector format/library i am working on.

1) Little or big? Dig files are written (version 4) in portable vector format which
is big endian byte order (note for David: I was wrong in my last mail). 
On little endian machines (i386 for example) byte order of each number must be 
changed. My test with d.vect says that such conversion takes 8% of time.
That is long time. The question is if we should keep big endian or change to little
endian. Exists any statistic about platforms used by GRASS users? Maybe 
ftp server log for binaries downloads could help, is it somewhere on the Web Markus?
Somebody knows any web page with informations about numbers of computers 
for each platform in use in the world? Any idea is welcome. 

2) It is possible to compile version 4 vector library with 
#define NO_PORTABLE  
and all vector files will be written in native format instead of portable.
Speed on little endian machine is increased but such non portable vector files
may be not be used on big endian computer then.
Somebody ever used such option?  Should be this feature keept in new vector
format/library? My suggestion is do not support that option and be sure that all vector
files in the world are always portable.

3) I want move header information (ORGANIZATION, DIGIT DATE, ....) from dig file 
into separate dighd text file - separate coordinates from other informations. 
Idea is taken from documents/grass6vector_api/vector/head.html.
I expect some changes in header fields in future (projection, units maybe) and changing 
dighd text format will be easier than changin binary file. This should also prepare
GRASS better for using OSVecDB where coordinates will be saved in DB table - I am not sure here.

4) I want remove bounding box from dig file because it is not reliable. Bounding box should
be saved in dig_plus only.



Radim

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