ST_CROSSES

Checks if two geometries cross. Returns 1 if they intersect but one does not cover the other, and the intersection dimension is less than the maximum dimension.

Syntax

ST_CROSSES(g1,g2)

Description

Returns 1 if geometry g1 spatially crosses geometry g2. Returns NULL if g1 is a Polygon or a MultiPolygon, or if g2 is a Point or a MultiPoint. Otherwise, returns 0.

The term spatially crosses denotes a spatial relation between two given geometries that has the following properties:

• The two geometries intersect.

• Their intersection results in a geometry that has a dimension that is one less than the maximum dimension of the two given geometries.

• Their intersection is not equal to either of the two given geometries.

ST_CROSSES() uses object shapes, while CROSSES(), based on the original MySQL implementation, uses object bounding rectangles.

Examples

SET @g1 = ST_GEOMFROMTEXT('LINESTRING(174 149, 176 151)');

SET @g2 = ST_GEOMFROMTEXT('POLYGON((175 150, 20 40, 50 60, 125 100, 175 150))');

SELECT ST_CROSSES(@g1,@g2);
+---------------------+
| ST_CROSSES(@g1,@g2) |
+---------------------+
|                   1 |
+---------------------+

SET @g1 = ST_GEOMFROMTEXT('LINESTRING(176 149, 176 151)');

SELECT ST_CROSSES(@g1,@g2);
+---------------------+
| ST_CROSSES(@g1,@g2) |
+---------------------+
|                   0 |
+---------------------+

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