As a new raster user I have found it extremely difficult to come to grips with the task of creating a raster table with postgis, in particular from an existing vector table, a task which is really trivial when done with some existing s/w packages ( i.e. SAGA, GRASS etc..). Most of the examples I could find were based on the use of raster2pgsql which implies the prior existence of a raster file created with an external package, not on using postgis native capabilities to create such a raster. If you already have a raster file, postgis has no problem creating a table from it, but what if you don't? Should you be forced to use one of the external packages? The postgis manual has a total of two (2) examples on how to create a raster table with st_asraster, although there are ten (10) different variants. My point is not a criticism of postgis raster, at the contrary, a suggestion that it could be much more useful if properly explained to users not familiar with it. In other words a good postgis raster tutorial would go a long way to convince users to at least try postgis raster by itself without recourse to external packages (except perhaps for the visualisation of the rasters). Specifically, how to create with postgis a raster table from a vector table, how to extract values from one of the vector attributes and store them in the raster, resulting in a raster identical to what would have been created with raster2pgsql. I, with my ignorance of the topic, have not been able to do that yet. If such a tutorial has already appeared somewhere I would be delighted to be pointed in that direction. Many thanks
-- View this message in context: http://postgis.17.x6.nabble.com/Postgis-raster-tutorial-tp5006124.html Sent from the PostGIS - User mailing list archive at Nabble.com. _______________________________________________ postgis-users mailing list [email protected] http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
