relatePattern

Returns true if the spatial relationship between geometries a and b matches the specified DE-9IM pattern.

DE-9IM pattern is a 9-character string described by the regular expression /^[F012T*]{9}$/.
Each character represents a dimension of intersection:

• F - no intersection (-1 dimension)
• 0 - point
• 1 - line
• 2 - area
• T - any intersection (0, 1 or 2)
• * - wildcard (F, 0, 1 or 2)

If possible it is better to use a named relationship functions like overlaps or covers.

warning

Do not use this function with invalid geometries. You will get unexpected results.

Parameters

Name	Type	Description
a	Geometry | Prepared<Geometry>	First geometry
b	Geometry	Second geometry
pattern	string	DE-9IM pattern, 9-character string where each character is one of F,0,1,2,T,*

Returns

boolean

true if the specified pattern matches the spatial relationship between geometries a and b

Throws

• GEOSError on unsupported geometry types (curved)

See also

• relate returns the exact DE-9IM matrix string for two geometries
• prepare improves performance of repeated calls against a single geometry

Examples

const a = polygon([ [ [ 0, 0 ], [ 0, 7 ], [ 4, 7 ], [ 4, 0 ], [ 0, 0 ] ] ]);
const b = polygon([ [ [ 2, 1 ], [ 2, 4 ], [ 8, 4 ], [ 8, 1 ], [ 2, 1 ] ] ]);
const ab_relation = relate(a, b); // '212101212'
const ab_overlaps = relatePattern(a, b, 'T*T***T**'); // true - `a` overlaps `b`, probably
const ab_contains = relatePattern(a, b, 'T*****FF*'); // false - `a` do not contain `b`

const a = polygon([ [ [ 0, 0 ], [ 0, 7 ], [ 4, 7 ], [ 4, 0 ], [ 0, 0 ] ] ]); const b = polygon([ [ [ 2, 1 ], [ 2, 4 ], [ 8, 4 ], [ 8, 1 ], [ 2, 1 ] ] ]); const ab_relation = relate(a, b); // '212101212' const ab_overlaps = relatePattern(a, b, 'T*T***T**'); // true - `a` overlaps `b`, probably const ab_contains = relatePattern(a, b, 'T*****FF*'); // false - `a` do not contain `b`