geo_intersection_line_with_polygon()

Applies to: ✅ Azure Data Explorer ✅ Azure Monitor ✅ Microsoft Sentinel

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

geo_intersection_line_with_polygon(lineString,polygon)

Learn more about syntax conventions.

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.

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.

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

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

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

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

The following line and polygon don't intersect.

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

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

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

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

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

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

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

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