geo_intersection_line_with_polygon()

Article
03/09/2023

Calculates the intersection of a line or a multiline with a polygon or a multipolygon.

Syntax

geo_intersection_line_with_polygon(lineString,polygon)

Parameters

Name	Type	Required	Description
lineString	`dynamic`	✔️	A LineString or MultiLineString in the GeoJSON format.
polygon	`dynamic`	✔️	A Polygon or MultiPolygon in the GeoJSON format.

Returns

Intersection in GeoJSON Format and of a dynamic data type. If lineString or a multiLineString or a polygon or a multipolygon are invalid, the query will produce a null result.

Note

The geospatial coordinates are interpreted as represented by the WGS-84 coordinate reference system.
The geodetic datum used to measure distance on Earth is a sphere. Line edges are geodesics on the sphere.
If input line or a polygon edges are straight cartesian lines, consider using geo_line_densify() or a geo_polygon_densify() in order to convert planar edges to geodesics.

LineString definition and constraints

dynamic({"type": "LineString","coordinates": [[lng_1,lat_1], [lng_2,lat_2], ..., [lng_N,lat_N]]})

dynamic({"type": "MultiLineString","coordinates": [[line_1, line_2, ..., line_N]]})

LineString coordinates array must contain at least two entries.
Coordinates [longitude, latitude] must be valid where longitude is a real number in the range [-180, +180] and latitude is a real number in the range [-90, +90].
Edge length must be less than 180 degrees. The shortest edge between the two vertices will be chosen.

Polygon definition and constraints

dynamic({"type": "Polygon","coordinates": [LinearRingShell, LinearRingHole_1, ..., LinearRingHole_N]})

dynamic({"type": "MultiPolygon","coordinates": [[LinearRingShell, LinearRingHole_1, ..., LinearRingHole_N],..., [LinearRingShell, LinearRingHole_1, ..., LinearRingHole_M]]})

LinearRingShell is required and defined as a counterclockwise ordered array of coordinates [[lng_1,lat_1],...,[lng_i,lat_i],...,[lng_j,lat_j],...,[lng_1,lat_1]]. There can be only one shell.
LinearRingHole is optional and defined as a clockwise ordered array of coordinates [[lng_1,lat_1],...,[lng_i,lat_i],...,[lng_j,lat_j],...,[lng_1,lat_1]]. There can be any number of interior rings and holes.
LinearRing vertices must be distinct with at least three coordinates. The first coordinate must be equal to the last. At least four entries are required.
Coordinates [longitude, latitude] must be valid. Longitude must be a real number in the range [-180, +180] and latitude must be a real number in the range [-90, +90].
LinearRingShell encloses at most half of the sphere. LinearRing divides the sphere into two regions. The smaller of the two regions will be chosen.
LinearRing edge length must be less than 180 degrees. The shortest edge between the two vertices will be chosen.
LinearRings must not cross and must not share edges. LinearRings may share vertices.
Polygon contains its vertices.

Tip

Use literal LineString or MultiLineString for better performance.

Examples

The following example calculates intersection between line and polygon. In this case, the result is a line.

Run the query

let lineString = dynamic({"type":"LineString","coordinates":[[-73.985195,40.788275],[-73.974552,40.779761]]});
let polygon = dynamic({"type":"Polygon","coordinates":[[[-73.9712905883789,40.78580561168767],[-73.98004531860352,40.775276834803655],[-73.97000312805176,40.77852663535664],[-73.9712905883789,40.78580561168767]]]});
print intersection = geo_intersection_line_with_polygon(lineString, polygon)

Output

intersection
{"type": "LineString","coordinates": [[-73.975611956578192,40.78060906714618],[-73.974552,40.779761]]}

The following example calculates intersection between line and polygon. In this case, the result is a multiline.

Run the query

let lineString = dynamic({"type":"LineString","coordinates":[[-110.522, 39.198],[-91.428, 40.880]]});
let polygon = dynamic({"type":"Polygon","coordinates":[[[-90.263,36.738],[-102.041,45.274],[-109.335,36.527],[-90.263,36.738]],[[-100.393,41.705],[-103.139,38.925],[-97.558,39.113],[-100.393,41.705]]]});
print intersection = geo_intersection_line_with_polygon(lineString, polygon)

Output

intersection
{"type": "MultiLineString","coordinates": [[[ -106.89353655881905, 39.769226209776306],[ -101.74448553679453, 40.373506008712525]],[[-99.136499431328858, 40.589336512699994],[-95.284527737311791, 40.799060242246348]]]}

The following line and polygon don't intersect.

Run the query

let lineString = dynamic({"type":"LineString","coordinates":[[1, 1],[2, 2]]});
let polygon = dynamic({"type":"Polygon","coordinates":[[[-73.9712905883789,40.78580561168767],[-73.98004531860352,40.775276834803655],[-73.97000312805176,40.77852663535664],[-73.9712905883789,40.78580561168767]]]});
print intersection = geo_intersection_line_with_polygon(lineString, polygon)

Output

intersection
{"type": "GeometryCollection","geometries": []}

The following example finds all roads in the NYC GeoJSON roads table that intersects with the area of interest literal polygon.

let area_of_interest = dynamic({"type":"Polygon","coordinates":[[[-73.95768642425537,40.80065354924362],[-73.9582872390747,40.80089719667298],[-73.95869493484497,40.80050736035672],[-73.9580512046814,40.80019873831593],[-73.95768642425537,40.80065354924362]]]});
NY_Manhattan_Roads
| project name = features.properties.Label, road = features.geometry
| project name, intersection = geo_intersection_line_with_polygon(road, area_of_interest)
| where array_length(intersection.geometries) != 0

Output

name	intersection
CentralParkW	{"type":"MultiLineString","coordinates":[[[-73.958295846836933,40.800316027289647],[-73.9582724,40.8003415]],[[-73.958413422194482,40.80037239620097],[-73.9584093,40.8003797]]]}
FrederickDouglassCir	{"type":"LineString","coordinates":[[-73.9579272943862,40.800751229494182],[-73.9579019,40.8007238],[-73.9578688,40.8006749],[-73.9578508,40.8006203],[-73.9578459,40.800570199999996],[-73.9578484,40.80053310000001],[-73.9578627,40.800486700000008],[-73.957913,40.800421100000008],[-73.9579668,40.8003923],[-73.9580189,40.80037260000001],[-73.9580543,40.8003616],[-73.9581237,40.8003395],[-73.9581778,40.8003365],[-73.9582724,40.8003415],[-73.958308,40.8003466],[-73.9583328,40.8003517],[-73.9583757,40.8003645],[-73.9584093,40.8003797],[-73.9584535,40.80041099999999],[-73.9584818,40.8004536],[-73.958507000000012,40.8004955],[-73.9585217,40.800562400000004],[-73.9585282,40.8006155],[-73.958416200000016,40.8007325],[-73.9583541,40.8007785],[-73.9582772,40.800811499999995],[-73.9582151,40.8008285],[-73.958145918999392,40.800839887820239]]}
W110thSt	{"type":"MultiLineString","coordinates":[[[-73.957828446036331,40.800476476316327],[-73.9578627,40.800486700000008]],[[-73.9585282,40.8006155],[-73.958565492035873,40.800631133466972]],[[-73.958416200000016,40.8007325],[-73.958446850928084,40.800744577466617]]]}
WestDr	{"type":"LineString","coordinates":[[-73.9580543,40.8003616],[-73.958009693938735,40.800250494588468]]}

The following example finds all counties in the USA that intersect with area of interest literal LineString.

Run the query

let area_of_interest = dynamic({"type":"LineString","coordinates":[[-73.97159099578857,40.794513338780895],[-73.96738529205322,40.792758888618756],[-73.96978855133057,40.789769718601505]]});
US_Counties
| project name = features.properties.NAME, county = features.geometry
| project name, intersection = geo_intersection_line_with_polygon(area_of_interest, county)
| where array_length(intersection.geometries) != 0

Output

name	intersection
New York	{"type": "LineString","coordinates": [[-73.971590995788574, 40.794513338780895], [-73.967385292053223, 40.792758888618756],[-73.969788551330566, 40.789769718601512]]}

The following example will return a null result because the LineString is invalid.

Run the query

let lineString = dynamic({"type":"LineString","coordinates":[[-73.985195,40.788275]]});
let polygon = dynamic({"type":"Polygon","coordinates":[[[-73.95768642425537,40.80065354924362],[-73.9582872390747,40.80089719667298],[-73.95869493484497,40.80050736035672],[-73.9580512046814,40.80019873831593],[-73.95768642425537,40.80065354924362]]]});
print is_invalid = isnull(geo_intersection_2lines(lineString, polygon))

Output

is_invalid
1

The following example will return a null result because the polygon is invalid.

Run the query

let lineString = dynamic({"type":"LineString","coordinates":[[-73.97159099578857,40.794513338780895],[-73.96738529205322,40.792758888618756],[-73.96978855133057,40.789769718601505]]});
let polygon = dynamic({"type":"Polygon","coordinates":[]});
print is_invalid = isnull(geo_intersection_2lines(lineString, polygon))

Output

is_invalid
1

geo_intersection_line_with_polygon()

Syntax

Parameters

Returns

Examples

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