[R-sig-Geo] FYI: Merging GIS and statistics --- RSAGA

[Roger Bivand]

On Wed, 30 Jan 2008, Johan Van de Wauw wrote:

> On Jan 30, 2008 10:59 AM, Roger Bivand <Roger.Bivand at nhh.no> wrote:
>
> If SAGA can make a source library for reading and writing its raster file
>> formats available to GDAL, and maybe help write a driver, SAGA access
>> through rgdal will happen automatically. Lots of other projects do this,
>> for example, the PCRaster format is included as source in the GDAL source.
>> Were SAGA to split out the raster I/O as a library and provide a copy to
>> GDAL, your question would be answered. SAGA does use GDAL for interfacing
>> other formats, and would be a "good citizen" if they reciprocated.
>>
>
> In fact, there is a module that imports and exports to GDAL in SAGA. It's
> code is rather simple, and I believe that bringing it to GDAL should not be
> a major issue. The SAGA format is nothing else than yet another binary
> gridfile with some kind of world-file attached to it. I've had the idea to
> bring this format in gdal for quite some time (in fact I once wrote a now
> obsolete export to gdal module for SAGA which I never released because I
> still wanted to tweak it(and the hyperfocus was gone...)). I'll cross-check
> with the saga-developers to see if somebody else is working on a
> gdal-implementation, and I might give it a try.

Please do - or if it is a BIL or similar, just saying which existing GDAL 
driver also works for SAGA would be great. If it is very similar, it might 
be enough to tweak a copy of an existing GDAL format.

>
> In the meantime I use R and SAGA frequently, and I just export to geotiff,
> which both programs read and write well. I didn't try RSAGA yet, but I see
> no reason why that's not possible.
>

That's very helpful. Could you please say whether the coordinate reference 
systems are recognised correctly on both sides, and if you need any extra 
arguments to write (presumably) using functions from the rgdal package?

Roger

-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no