geospatial

This library provides a geospatial_protocol protocol and a geospatial object for common geographic computations over coordinates represented as (Latitude,Longitude). By default, distances are returned in kilometers.

API documentation

Open the ../../apis/library_index.html#geospatial link in a web browser.

Loading

To load all entities in this library, load the loader.lgt file:

| ?- logtalk_load(geospatial(loader)).

Testing

To test this library predicates, load the tester.lgt file:

| ?- logtalk_load(geospatial(tester)).

Available predicates

The library currently includes predicates for:

  • Coordinate validation

  • Coordinate normalization helpers

  • Point-to-point distances (haversine and vincenty)

  • Rhumb-line distance, bearing, and destination predicates

  • Rhumb-line interpolation and midpoint helpers

  • Generic distance dispatch (distance/4 and distance/5)

  • Initial and final bearings

  • Midpoint and destination point computations

  • Great-circle interpolation and track-distance helpers

  • Proximity checks and nearest coordinate search

  • Mean center and coordinates bounding boxes

  • Minimum enclosing circle helper

  • Coordinates-to-bounding-box conversion helper

  • Equirectangular projection and inverse helpers

  • Point-in-polygon checks

  • Polygon area, polygon centroid, and polygon bounding boxes

  • Polygon closure and orientation helpers

  • Polygon orientation normalization helpers

  • Polygon validity checks

  • Bounding-box utilities

  • Nearest-point and point-to-polyline distance helpers

  • Polyline length and polygon perimeter

  • Polyline simplification by tolerance

  • Polyline split and resampling helpers

  • Polygon intersection checks

  • Spherical bounding boxes

  • Route distance accumulation (route_distance/2, route_distance/3, and route_distance/4)

For explicit units, predicates distance/5 and route_distance/4 support kilometers, meters, miles, and nautical_miles.

Generic metric dispatch accepts rhumb (and alias loxodrome) in addition to existing spherical and ellipsoidal metrics.

Notes

The generic vector distance predicates already available in the types library (notably in the listp and numberlistp protocols) remain the recommended choice for non-geographic n-dimensional data.

Usage

Load the library:

| ?- logtalk_load(geospatial(loader)).

Validate a coordinate:

| ?- geospatial::valid_coordinate((38.7223, -9.1393)).

Normalize coordinates and convert to/from local planar coordinates:

| ?- geospatial::normalize_coordinate((95.0, 10.0), Normalized).
| ?- geospatial::equirectangular_projection((38.7223, -9.1393), 38.0, X, Y).
| ?- geospatial::equirectangular_inverse(X, Y, 38.0, Coordinate).

Compute default distance in kilometers (Haversine):

| ?- geospatial::distance((38.7223, -9.1393), (41.1579, -8.6291), haversine, Distance).
| ?- geospatial::rhumb_distance((38.7223, -9.1393), (41.1579, -8.6291), Distance).
| ?- geospatial::rhumb_bearing((38.7223, -9.1393), (41.1579, -8.6291), Bearing).
| ?- geospatial::rhumb_destination_point((38.7223, -9.1393), 45.0, 50.0, Destination).
| ?- geospatial::interpolate_rhumb((38.7223, -9.1393), (41.1579, -8.6291), 0.5, Intermediate).
| ?- geospatial::rhumb_midpoint((38.7223, -9.1393), (41.1579, -8.6291), Midpoint).

Compute distance with explicit unit (meters, miles, or nautical_miles):

| ?- geospatial::distance((38.7223, -9.1393), (41.1579, -8.6291), vincenty, miles, Distance).

Compute route distance using the default metric (haversine) in kilometers:

| ?- geospatial::route_distance([(38.7223, -9.1393), (39.7440, -8.8070), (41.1579, -8.6291)], Distance).

Compute route distance with explicit metric and unit:

| ?- geospatial::route_distance([(38.7223, -9.1393), (39.7440, -8.8070), (41.1579, -8.6291)], vincenty, nautical_miles, Distance).

Compute midpoint and destination point:

| ?- geospatial::midpoint((38.7223, -9.1393), (41.1579, -8.6291), Midpoint).
| ?- geospatial::destination_point((38.7223, -9.1393), 45.0, 50.0, Destination).
| ?- geospatial::interpolate_great_circle((38.7223, -9.1393), (41.1579, -8.6291), 0.5, Intermediate).
| ?- geospatial::cross_track_distance((40.0, -9.0), (38.7223, -9.1393), (41.1579, -8.6291), CrossTrackKm).
| ?- geospatial::along_track_distance((40.0, -9.0), (38.7223, -9.1393), (41.1579, -8.6291), AlongTrackKm).

Compute final bearing and proximity checks:

| ?- geospatial::final_bearing((38.7223, -9.1393), (41.1579, -8.6291), Bearing).
| ?- geospatial::within_distance((38.7223, -9.1393), (41.1579, -8.6291), 300.0, haversine).

Find the nearest coordinate from a list:

| ?- geospatial::nearest_coordinate((38.7223, -9.1393), [(37.7749, -122.4194), (41.1579, -8.6291), (40.4168, -3.7038)], vincenty, Nearest, Distance).

Compute center and coordinate-list bounding boxes:

| ?- geospatial::mean_center([(38.7223, -9.1393), (41.1579, -8.6291), (40.4168, -3.7038)], Center).
| ?- geospatial::minimum_enclosing_circle([(38.7223, -9.1393), (41.1579, -8.6291), (40.4168, -3.7038)], Center, Radius).
| ?- geospatial::coordinates_bounding_box([(38.7223, -9.1393), (41.1579, -8.6291), (40.4168, -3.7038)], BoundingBox).
| ?- geospatial::bbox_from_coordinates([(38.7223, -9.1393), (41.1579, -8.6291), (40.4168, -3.7038)], BoundingBox).

Work with polygons:

| ?- geospatial::point_in_polygon((0.5, 0.5), [(0.0, 0.0), (0.0, 1.0), (1.0, 1.0), (1.0, 0.0)]).
| ?- geospatial::polygon_area([(0.0, 0.0), (0.0, 1.0), (1.0, 1.0), (1.0, 0.0)], Area).
| ?- geospatial::polygon_centroid([(0.0, 0.0), (0.0, 1.0), (1.0, 1.0), (1.0, 0.0)], Centroid).
| ?- geospatial::polygon_bounding_box([(1.0, -2.0), (0.0, 1.0), (-1.0, -1.0)], BoundingBox).
| ?- geospatial::close_polygon([(0.0, 0.0), (0.0, 1.0), (1.0, 0.0)], ClosedPolygon).
| ?- geospatial::polygon_orientation([(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)], Orientation).
| ?- geospatial::is_clockwise_polygon([(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)]).
| ?- geospatial::normalize_polygon_orientation([(0.0, 0.0), (0.0, 1.0), (1.0, 1.0), (1.0, 0.0)], clockwise, Oriented).
| ?- geospatial::clockwise_polygon([(0.0, 0.0), (0.0, 1.0), (1.0, 1.0), (1.0, 0.0)], Clockwise).
| ?- geospatial::counterclockwise_polygon([(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)], Counterclockwise).
| ?- geospatial::is_valid_polygon([(0.0, 0.0), (0.0, 1.0), (1.0, 0.0)]).

Work with bounding boxes:

| ?- geospatial::bbox_contains(bbox((-1.0, -1.0), (1.0, 1.0)), (0.5, 0.5)).
| ?- geospatial::bbox_intersects(bbox((0.0, 0.0), (1.0, 1.0)), bbox((0.5, 0.5), (2.0, 2.0))).
| ?- geospatial::bbox_union(bbox((0.0, 0.0), (1.0, 1.0)), bbox((-1.0, 0.5), (0.5, 2.0)), BoundingBox).
| ?- geospatial::bbox_expand(bbox((0.0, 0.0), (0.0, 0.0)), 111.195, ExpandedBoundingBox).

Compute nearest points and distances to paths:

| ?- geospatial::nearest_point_on_segment((1.0, 1.0), (0.0, 0.0), (0.0, 2.0), Nearest).
| ?- geospatial::nearest_point_on_polyline((1.0, 1.0), [(0.0, 0.0), (0.0, 2.0), (2.0, 2.0)], Nearest, Distance).
| ?- geospatial::point_to_polyline_distance((1.0, 1.0), [(0.0, 0.0), (0.0, 2.0)], Distance).

Compute polyline and polygon lengths:

| ?- geospatial::polyline_length([(0.0, 0.0), (0.0, 1.0), (0.0, 2.0)], Length).
| ?- geospatial::polyline_length([(0.0, 0.0), (0.0, 1.0)], vincenty, Length).
| ?- geospatial::polyline_simplify([(0.0, 0.0), (0.5, 0.1), (1.0, 0.0)], 20.0, Simplified).
| ?- geospatial::polyline_split_at_distance([(0.0, 0.0), (0.0, 1.0), (0.0, 2.0)], 111.195, Left, Right).
| ?- geospatial::polyline_resample([(0.0, 0.0), (0.0, 1.0), (0.0, 2.0)], 50.0, Resampled).
| ?- geospatial::polygon_perimeter([(0.0, 0.0), (0.0, 1.0), (1.0, 1.0), (1.0, 0.0)], Perimeter).

Check polygon intersections:

| ?- geospatial::polygons_intersect([(0.0, 0.0), (0.0, 2.0), (2.0, 2.0), (2.0, 0.0)], [(1.0, 1.0), (1.0, 3.0), (3.0, 3.0), (3.0, 1.0)]).