[Freegis-list] C library for raster algebra

[Ari Jolma]

Hi all,

I repackaged the raster algebra / hydrological terrain analysis C 
library from my old Grid.pm Perl module into a separate module and 
uploaded it to sourceforge: http://sourceforge.net/projects/libral/

By repackaging I mean support for the standard GNU build system 
(./configure; make; make install).

One reason for doing that was my colleague's effort in making a 
MapWindow (www.mapwindow.com) add-on from the library. Mapwindow is not 
free as in freedom, thus it would be nice to prepare for example a QGIS 
add-from the library. Another reason is my intention of writing chapters 
into freegisbook. In those chapters I will use the library and its Perl 
interface for examples.

To make the raster algebra functionality useful really requires a 
high-level language interface, thus the Perl module. Maybe somebody is 
interested in making a Python interface? I am fond of using the library 
through Perl in interactive Perl shell but for casual users the shell 
should be somehow integrated with a GIS. I'm going to eventually upload 
my Perl module to CPAN as something like Geo::RasterAlgebra.

I categorized the library as "production/stable" in sourceforge but it 
would benefit from more development attention:

- the i/o of the library is not very good, there is support for ESRI 
.hdr / BIL format and something else but it is assumed that if the 
library is linked to a system, the system should provide those services
- the library supports only two data types: short (two byte int) and 
float (four byte real) and the whole raster is stored in RAM as one 
large block, this is for simplicity, speed, and size
- the terrain/hydrological analysis library is rather experimental and 
not complete

I welcome new developers for the project as well as ideas and 
suggestions for how to integrate the library to other freegis software 
and make it interoperable.

libral is GPL software.

Cheers,

Ari

-- 
Ari Jolma, ari.jolma at hut.fi, Professor of Geoinformatics
Helsinki University of Technology
POBox 1200, 02015 TKK, Finland
http://www.hut.fi/~jolma