Commit dc24c942 authored by Paul Ramsey's avatar Paul Ramsey

Updates for 2.0


git-svn-id: http://svn.osgeo.org/postgis/trunk@9542 b70326c6-7e19-0410-871a-916f4a2858ee
parent 09205909
For updated credits, see the postgis manual.
For updated credits, see the PostGIS manual.
Offline: see doc/README
Online: http://www.postgis.org/documentation/manual-svn/postgis_introduction.html#credits
PostGIS 2.0 Migration Guide
===========================
PostGIS 2.0 introduces changes that may affect backward compatibility
PostGIS 2.0 introduces changes that may affect backwards compatibility
for some applications. This document lists those changes.
Deprecated Functions Removed
----------------------------
Since PostGIS 1.2, we have been encouraging users to use functions with the ST_
prefix. The ST_ prefixed functions are part of the ISO SQL/MM standard and
used by other spatial SQL databases, so we want to conform as closely to the
industry usage as we can.
At 2.0, we have finally removed the old functions. If you have an application
that *still* requires the old function signatures, please look to the legacy_*.sql
files to add the old signatures back in.
If you are using MapServer, upgrade to the latest versions of the 6.0 or 6.2
releases. For earlier releases, you will have to install the legacy.sql files.
Unknown SRID
------------
The "unknown SRID", assigned to geometries when SRID is not specified, is now 0, not -1.
ST_SRID will now return 0 when called on a geometry with no known SRID.
ST_AsBinary, ST_AsText and 3D
-----------------------------
Previous versions of PostGIS returned 2D versions of objects when ST_AsBinary
and ST_AsText were called. PostGIS 2.0 returns ISO SQL/MM versions when 3D or 4D
objects are used. For example, a 3D point with a Z dimension will return
as 'POINT Z (0 0 0)'. A 4D point will return as 'POINT ZM (0 0 0 0)'.
For WKB, extra dimensionality is indicated in the type numbers. The Z, M, and ZM
type numbers are indicated by adding 1000, 2000, and 3000 respectively to the
usual 2D type numbers. So, for example, a 2D Point has a type number of 1. A 4D
PointZM has a type number of 3001. A 2D polygon has a type number of 3. A PolygonZ has a
type number of 2003.
geometry_columns
----------------
......@@ -17,7 +55,7 @@ a table to a view.
* Applications that have inserted directly into ``geometry_columns``
will need to either move to the standard functions, or change
their create table syntax to include type/srid/dimsionality
their create table syntax to include type/srid/dimensionality
information.
For example, to specify a 3D feature in WGS84::
......
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