From: Regina Obe Date: Sat, 21 Nov 2009 03:44:12 +0000 (+0000) Subject: update st_buffer, st_intersection details for geography to reflect what we are actual... X-Git-Tag: 1.5.0b1~196 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=fa514a4d192832c241c356228b4781e8dddb2bfb;p=postgis update st_buffer, st_intersection details for geography to reflect what we are actually doing in bestsrid calc git-svn-id: http://svn.osgeo.org/postgis/trunk@4876 b70326c6-7e19-0410-871a-916f4a2858ee --- diff --git a/doc/reference_processing.xml b/doc/reference_processing.xml index 34863c385..e2bd1d3ac 100644 --- a/doc/reference_processing.xml +++ b/doc/reference_processing.xml @@ -52,7 +52,7 @@ are in the Spatial Reference System of the geometry. Introduced in 1.5 support for different end cap and mitre settings to control shape. Geography: For geography this is really a thin wrapper around the geometry implementation. It first determines the best SRID that - fits the bounding box of the geography object (favoring UTM, polar stereographic and falling back on mercator in worst case scenario) and then buffers in that planar spatial ref and retransforms back to WGS84 geography. + fits the bounding box of the geography object (favoring UTM, Lambert Azimuthal Equal Area (LAEA) north/south pole, and falling back on mercator in worst case scenario) and then buffers in that planar spatial ref and retransforms back to WGS84 geography. For geography this may not behave as expected if object is sufficiently large that it falls between two UTM zones or crosses the dateline Availability: 1.5 - ST_Buffer was enhanced to support different endcaps and join types. These are useful for example to convert road linestrings @@ -959,9 +959,8 @@ SELECT ST_AsEWKT(geom) As the_geom, path ST_Intersection in conjunction with ST_Intersects is very useful for clipping geometries such as in bounding box, buffer, region queries where you only want to return that portion of a geometry that sits in a country or region of interest. - Geography: For geography this is really a thin wrapper around the geometry implementation. It first determines the best SRID that - fits the bounding box of the geography object (favoring UTM, polar stereographic and falling back on mercator in worst case scenario) and then buffers in that planar spatial ref and retransforms back to WGS84 geography. + fits the bounding box of the 2 geography objects (if geography objects are within one half zone UTM but not same UTM will pick one of those) (favoring UTM or Lambert Azimuthal Equal Area (LAEA) north/south pole, and falling back on mercator in worst case scenario) and then intersection in that best fit planar spatial ref and retransforms back to WGS84 geography. Do not call with a GEOMETRYCOLLECTION as an argument