[postgis-devel] [PostGIS] #1858: Raster dataset functionality

[PostGIS]

#1858: Raster dataset functionality
-------------------------+--------------------------------------------------
 Reporter:  bnordgren    |       Owner:  pracine      
     Type:  enhancement  |      Status:  new          
 Priority:  medium       |   Milestone:  PostGIS 2.1.0
Component:  raster       |     Version:  2.0.x        
 Keywords:               |  
-------------------------+--------------------------------------------------
 I was playing around with a means of treating a table of raster data as if
 each row were a "block" in gdal or a tile in Java2D/JAI. The basic
 addition here is a "dataset" raster having only one band, where each
 "pixel" is a foreign key to the actual block with all the pixel data. Most
 operations are then two-phase: lookup the key in the "dataset", then
 perform the operation on the correct "block".

 For this to work the way I wrote it, the table of raster blocks must have
 a "serial" primary key column. Also, it will only handle regularly tiled
 data (but tiles can be missing).

 I'm attaching preliminary code for inferring a "dataset" from a pool of
 blocks having a filename field, code to read/write raster blocks and code
 to read/write pixels using the original (in file) pixel coordinates.

 For this to represent an improvement, the "dataset" raster is going to
 have to be persisted in a table along with certain other information
 (srid, num_bands, pixel_types, nodata_values, etc.). Doing this with
 PostGIS functions rather than requiring all connecting applications to
 "roll-their-own" dataset constructs may aid interoperability.

 The attached code is useful to get an idea of what will need to be stored
 in the "dataset table" (or view). Once the table is created, functions
 with smaller parameter lists can be fabricated because they can just
 reference the information in the table.

 Enjoy.

-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/1858>
PostGIS <http://trac.osgeo.org/postgis/>
The PostGIS Trac is used for bug, enhancement & task tracking, a user and developer wiki, and a view into the subversion code repository of PostGIS project.