ST_MaxX

ST_MaxX takes a geometry as an input parameter and returns its maximum X coordinate.

If the given geometry is null or is empty, then null is returned.

Syntax

Parameter

geometry: A value of one of the seven distinct data types for which the maximum X coordinate is returned.

Return type

DOUBLE

Examples

Example 1

This example illustrates the use of the ST_MaxX function. Three polygons are created and inserted into the SAMPLE_POLYS table. The third example illustrates how you can use all of the functions that return the maximum and minimum coordinate values to assess the spatial range of the geometries that are stored in a particular spatial column.


SET CURRENT PATH = CURRENT PATH, db2gse;
CREATE TABLE sample_polys (id INTEGER, geometry ST_Polygon);

INSERT INTO sample_polys
  VALUES (1, ST_Polygon('polygon zm ((110 120 20 3,
                                      110 140 22 3,
                                      120 130 26 4,
                                      110 120 20 3))', 0) );

INSERT INTO sample_polys
  VALUES (2, ST_Polygon('polygon zm ((0 0 40 7,
                                      0 4 35 9,
                                      5 4 32 12,
                                      5 0 31 5,
                                      0 0 40 7))', 0) );

INSERT INTO sample_polys
  VALUES (3, ST_Polygon('polygon zm ((12 13 10 16,
                                      8 4 10 12,
                                      9 4 12 11,
                                      12 13 10 16))', 0) );

Example 2

This example finds the maximum X coordinate of each polygon in SAMPLE_POLYS.


SELECT id, CAST ( ST_MaxX(geometry) AS INTEGER) MAX_X_COORD
  FROM sample_polys;

Results:


ID          MAX_X_COORD
----------- ------------
          1          120
          2            5
          3           12

Example 3

This example finds the maximum X coordinate that exists for all polygons in the GEOMETRY column.


SELECT CAST ( MAX ( ST_MaxX(geometry) ) AS INTEGER) OVERALL_MAX_X
  FROM sample_polys;

Results:


OVERALL_MAX_X
--------------
           120

Example 4

This example finds the spatial extent (overall minimum to overall maximum) of all the polygons in the SAMPLE_POLYS table. This calculation is typically used to compare the actual spatial extent of the geometries to the spatial extent of the spatial reference system associated with the data to determine if the data has room to grow.


SELECT CAST ( MIN (ST_MinX (geometry)) AS INTEGER) MIN_X,
       CAST ( MIN (ST_MinY (geometry)) AS INTEGER) MIN_Y,
       CAST ( MIN (ST_MinZ (geometry)) AS INTEGER) MIN_Z,
       CAST ( MIN (ST_MinM (geometry)) AS INTEGER) MIN_M,
       CAST ( MAX (ST_MaxX (geometry)) AS INTEGER) MAX_X,
       CAST ( MAX (ST_MaxY (geometry)) AS INTEGER) MAX_Y,
       CAST ( MAX (ST_MaxZ (geometry)) AS INTEGER) MAX_Z,
       CAST ( MAX (ST_MaxM (geometry)) AS INTEGER) MAX_M,
  FROM sample_polys;

Results:


MIN_X     MIN_Y     MIN_Z     MIN_M     MAX_X     MAX_Y     MAX_Z     MAX_M
--------- --------- --------- --------- --------- --------- --------- ----------
        0         0        10         3       120       140        40         16