MySQL does not yet implement the following GIS features:
Additional Metadata Views
OpenGIS specifications propose several additional metadata
views. For example, a system view named
GEOMETRY_COLUMNS
contains a description of
geometry columns, one row for each geometry column in the
database.
The OpenGIS function Length()
on
LineString
and
MultiLineString
currently should be called
in MySQL as GLength()
The problem is that there is an existing SQL function
Length()
that calculates the length of
string values, and sometimes it is not possible to distinguish
whether the function is called in a textual or spatial
context. We need either to solve this somehow, or decide on
another function name.