Changes between Version 26 and Version 27 of WKTRasterGSoC

Timestamp:

Apr 2, 2013, 3:37:31 PM (11 years ago)

Author:

robe

Comment:

—

WKTRasterGSoC

@@ -13 +13 @@
 
 
-'''2) An optimized version of the two rasters ST_MapAlgebra SQL function'''
+~~ '''2) An optimized version of the two rasters ST_MapAlgebra SQL function'''
 
  Mentor: Pierre Racine (pierre.racine at sbf.ulaval.ca)
@@ -22 +22 @@
  A [http://postgis.refractions.net/documentation/manual-svn/RT_ST_MapAlgebraExpr2.html two rasters version of the ST_MapAlgebra SQL function already exist]. It allows a PostGIS user to create a new raster coverage as a function of two existing one with a simple SQL query. e.g.: SELECT ST_MapAlgebra(rast1, rast2, "(rast1 + rast2) / 2") FROM coverage1, coverage2 WHERE ST_Intersects(rast1, rast2). The extent of the resulting raster can be equivalent to the extent of the FIRST, the SECOND, the INTERSECTION or the UNION of both raster.
 
- The current implementation compute the new raster one pixel at a time. It is possible, but complicated, to optimize the algorythm in order to fill many areas as a chunck of data instead of pixels by pixels. The project includes reviewing the proposed algorythm and implementing it. You will familiarize yourself with PostGIS development (the most used open source geospatial database), geospatial imagery concepts, open source development tools and code in C and PL/pgSQL.
+ The current implementation compute the new raster one pixel at a time. It is possible, but complicated, to optimize the algorythm in order to fill many areas as a chunck of data instead of pixels by pixels. The project includes reviewing the proposed algorythm and implementing it. You will familiarize yourself with PostGIS development (the most used open source geospatial database), geospatial imagery concepts, open source development tools and code in C and PL/pgSQL. ~~~