[postgis-devel] [PostGIS] #795: [raster] ST_Intersects raster documentation is confusing

PostGIS trac at osgeo.org
Wed Jan 19 13:32:41 PST 2011


#795: [raster] ST_Intersects raster documentation is confusing
----------------------------+-----------------------------------------------
 Reporter:  pracine         |       Owner:  pracine      
     Type:  enhancement     |      Status:  new          
 Priority:  medium          |   Milestone:  PostGIS 2.0.0
Component:  postgis raster  |     Version:  trunk        
 Keywords:                  |  
----------------------------+-----------------------------------------------
 The description says: "Returns true if any pixel in a raster band has a
 value that is not nodatavalue and that geometry region of the pixel
 intersects the geometry. If hasnodata is passed in, then it will use that
 to consider if it needs to analyze pixels (true) means analyze pixels, if
 the convexhull intersects the geometry. false means just return true if
 the convex hull of the raster intersects with the geometry. If hasnodata
 is omitted, it reads the value from the meta data of the raster."

 The last part of the sentence is false.

 Better proposition:

 -"Returns true if the geometry intersects with the raster. Nodata values
 are taken into account so that if the geometry intersects only with nodata
 values, the function returns false. hasnodata may modify this behavior: if
 set to false, nodata value are not taken into account and the function
 returns true as soon as the geometry intersects with the convex hull of
 the raster."

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/795>
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