I have been receiving many emails lately about the support for SAGA and GRASS in SEXTANTE, how to configure it and what is our policy about that. Also, I am helping a colleague to create the custom distribution for the SEXTANTE course organized by the gvSIG Association that he will teach in October, and a few similar issues have arisen. For this reason, I am writing this entry to clarify all this, hoping that it will help users and integrators of SEXTANTE.
The main idea is that, due to inestability problems, we have decided that the installation process has to be done in advance and cannot be done by the user. Letting the user do this is error-prone, since different versions can be used and there are many others things than have to be controlled. We believe that this in not good for SEXTANTE, so we will support only preconfigured systems.
For this reason, the SAGA and GRASS providers will only be available if the application includes SAGA and GRASS and they are correctly preconfigured.
So far, this is the situation regarding the main GIS software that uses SEXTANTE:
-gvSIG CE will ship with both and SAGA and GRASS, and will be thus complete with all algorithms.
-Official gvSIG will ship (AFAIK) without them, and will have no support for SAGA and GRASS. This might, however, change, since we are working with them to prepare for their next release and we haven't discussed that carefully. Right now, there are two different bindings for these two flavors of gvSIG, and the SAGA/GRASS support is the main difference between them (though not the only one)
-SEXTANTE for ArcGIS will include a running version of SAGA (Windows only), but no GRASS, since we are not completely happy with the behaviour of the SEXTANTE/GRASS interface when running under ArcGIS. This distribution can already be downloaded from our website (still a beta, not a final release).
-OpenJUMP will have no support for external providers (mainly due to our lack of time to work on it...sorry)