geolineshape

Line shape in geographic coordinates

Since R2021b

Description

A geolineshape object represents a line or multiline in geographic coordinates. A multiline is an individual line shape that contains a set of separate lines.

To represent a line or multiline in planar coordinates, use a maplineshape object instead.

Creation

To create geolineshape objects, either:

• Import line data in geographic coordinates as a geospatial table using the readgeotable function, and then query the Shape variable of the table.

• Use the geolineshape function (described here).

Syntax

shape = geolineshape(lat,lon)

Description

shape = geolineshape(lat,lon) creates a geolineshape object or array of geolineshape objects with vertices at the specified latitude and longitude coordinates. The sizes of lat, lon, and the geolineshape object array shape match.

Input Arguments

lat — Latitude coordinates

numeric vector | cell array of numeric vectors

Latitude coordinates, specified as a numeric vector or a cell array of numeric vectors.

• Create a line by specifying a vector, such as [65 62 53 66].

• Create a multiline by specifying a vector and including line breaks as NaN values, such as [55 34 18 NaN 14 19 42 26].

• Create an array of lines and multilines by specifying a cell array of vectors, such as {[55 34 18],[14 19 NaN 42 26 31]}.

The NaN values in lat must correspond to the NaN values in lon.

The size of lat must match the size of lon. For cell arrays, the size of the vector in each cell of lat must match the size of the vector in the corresponding cell of lon.

Data Types: double | cell

lon — Longitude coordinates

numeric vector | cell array of numeric vectors

Longitude coordinates, specified as a numeric vector or a cell array of numeric vectors.

• Create a line by specifying a vector, such as [4 59 121 98].

• Create a multiline by specifying a vector and including line breaks as NaN values, such as [78 56 63 NaN 83 106 104 126].

• Create an array of lines and multilines by specifying a cell array of vectors, such as {[78 56 63],[83 106 NaN 104 126 131]}.

The NaN values in lat must correspond to the NaN values in lon.

The size of lat must match the size of lon. For cell arrays, the size of the vector in each cell of lat must match the size of the vector in the corresponding cell of lon.

Data Types: double | cell

Properties

NumParts — Number of line parts

array of nonnegative integers

This property is read-only.

Number of line parts, returned as an array of nonnegative integers.

For a geolineshape scalar, the value of NumParts is 1 when the geolineshape object represents a single line and more than 1 when the object represents a multiline.

For a geolineshape array, the size of NumParts matches the size of the array.

Data Types: double

Geometry — Geometric type

"line" (default)

This property is read-only.

Geometric type, returned as "line".

Data Types: string

CoordinateSystemType — Coordinate system type

"geographic" (default)

This property is read-only.

Coordinate system type, returned as "geographic".

Data Types: string

GeographicCRS — Geographic coordinate reference system

[] (default) | geocrs object

Geographic coordinate reference system (CRS), specified as a geocrs object. A geographic CRS consists of a datum (including its ellipsoid), prime meridian, and angular unit of measurement.

Object Functions

geoplot	Plot points, lines, and polygons on map
geoclip	Clip geographic shape to latitude-longitude limits
linelength	Length of line shape in geographic or planar coordinates
ismultipoint	Determine which array elements are multipoint shapes

Examples

Get Information About Imported Geographic Lines

Import the tracks layer of a GPX file containing routes in Massachusetts as a geospatial table. The tracks layer represents the routes using lines. Get information about the line in the second track by querying the Shape variable of the table.

GT = readgeotable("sample_tracks.gpx",Layer="tracks");
GT.Shape(2)

ans = 
  geolineshape with properties:

                NumParts: 5
                Geometry: "line"
    CoordinateSystemType: "geographic"
           GeographicCRS: [1×1 geocrs]

Create a subtable that contains the second track. Display the second track on a road map.

GT2 = GT(2,:);
geoplot(GT2,LineWidth=2)
geobasemap streets

Create Geographic Lines and Multilines

Create an individual line as a geolineshape scalar. Specify the geographic CRS as the World Geodetic System of 1984, which has the EPSG code 4326.

lat = [65 62 53 66];
lon = [4 59 121 98];
lineshp = geolineshape(lat,lon);

g = geocrs(4326);
lineshp.GeographicCRS = g

lineshp = 
  geolineshape with properties:

                NumParts: 1
                Geometry: "line"
    CoordinateSystemType: "geographic"
           GeographicCRS: [1x1 geocrs]

Create a multiline as a geolineshape scalar.

lat = [55 34 18 NaN 14 19 42 26];
lon = [78 56 63 NaN 83 106 104 126];
multiline = geolineshape(lat,lon);
multiline.GeographicCRS = g

multiline = 
  geolineshape with properties:

                NumParts: 2
                Geometry: "line"
    CoordinateSystemType: "geographic"
           GeographicCRS: [1x1 geocrs]

Create one individual line and one multiline as a 1-by-2 geolineshape array.

lat = {[55 34 18],[14 19 NaN 42 26 37]};
lon = {[78 56 63],[83 106 NaN 104 126 113]};
lineMultiline = geolineshape(lat,lon);
lineMultiline.GeographicCRS = g

lineMultiline=1×2 geolineshape array with properties:
                NumParts: [1 2]
                Geometry: "line"
    CoordinateSystemType: "geographic"
           GeographicCRS: [1x1 geocrs]

Version History

Introduced in R2021b