geoclip

Read worldwide land areas as a geospatial table. Extract the polygon shapes.

land = readgeotable("landareas.shp");
shape = land.Shape

shape=537×1 geopolyshape array with properties:
              NumRegions: [537x1 double]
                NumHoles: [537x1 double]
                Geometry: "polygon"
    CoordinateSystemType: "geographic"
           GeographicCRS: [1x1 geocrs]
      ⋮

Specify the latitude and longitude limits for an area containing part of Asia. Then, clip the shapes.

latlim = [4 42];
lonlim = [65 130];
clipped = geoclip(shape,latlim,lonlim);

Display the clipped shapes on a map with no basemap. Display the bounding box as a rectangle.

figure
geobasemap none
hold on
geoplot(clipped)
geoplot(latlim([1 2 2 1 1]),lonlim([1 1 2 2 1]),"k")

Since R2024b

Read the locations of world cities as a geospatial table. The table represents the cities using point shapes in geographic coordinates. Extract the point shapes.

cities = readgeotable("worldcities.shp");
shape = cities.Shape

shape = 
  318×1 geopointshape array with properties:

               NumPoints: [318×1 double]
                Latitude: [318×1 double]
               Longitude: [318×1 double]
                Geometry: "point"
    CoordinateSystemType: "geographic"
           GeographicCRS: [1×1 geocrs]

Specify the clipper polygon. Create a geospatial table that contains a point shape object for Detroit. Then, define an area of interest (AOI) by creating a circle with a radius of 8 degrees that is centered on the point shape.

detroit = geocode("Detroit","city");
clipperPolygon = aoicircle(detroit,8);

Verify that the city locations and the clipper polygon use the same geographic coordinate reference system (CRS).

isequal(shape.GeographicCRS,clipperPolygon.GeographicCRS)

ans = logical
   1

Clip the city locations to the AOI.

clipped = geoclip(shape,clipperPolygon);

Create a map that displays the clipped city locations and the AOI.

figure
geoplot(clipped,MarkerSize=15)
hold on
geoplot(clipperPolygon,FaceColor="none")

Read the names and locations of world cities as a geospatial table. Extract the point shapes.

cities = readgeotable("worldcities.shp");
shape = cities.Shape

shape = 
  318x1 geopointshape array with properties:

               NumPoints: [318x1 double]
                Latitude: [318x1 double]
               Longitude: [318x1 double]
                Geometry: "point"
    CoordinateSystemType: "geographic"
           GeographicCRS: [1x1 geocrs]

Specify the latitude and longitude limits for an area containing part of Asia. Then, clip the shapes.

latlim = [4 42];
lonlim = [65 130];
clipped = geoclip(shape,latlim,lonlim);

When a point shape lies outside the specified limits, the clipped shape has no coordinate data and the NumPoints property is 0. Remove shapes with no coordinate data from the clipped shapes.

idx = clipped.NumPoints ~= 0;
clipped = clipped(idx)

clipped = 
  57x1 geopointshape array with properties:

               NumPoints: [57x1 double]
                Latitude: [57x1 double]
               Longitude: [57x1 double]
                Geometry: "point"
    CoordinateSystemType: "geographic"
           GeographicCRS: [1x1 geocrs]

When a line or polygon shape has no coordinate data, its respective NumParts or NumRegions property is 0.

Create a line shape in geographic coordinates from global coastline data. The longitude coordinates are in the range of –180 to 180 degrees.

load coastlines
coast = geolineshape(coastlat,coastlon)

coast = 
  geolineshape with properties:

                NumParts: 241
                Geometry: "line"
    CoordinateSystemType: "geographic"
           GeographicCRS: []

Shift the longitude coordinates so they are in the range of 0 to 360 degrees.

coastShift = geoclip(coast,[-90 90],[0 360]);

Display the shifted line shape on a map.

figure
geobasemap none
hold on
geoplot(coastShift)