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wmpolygon

Display geographic polygon on web map

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Syntax

wmpolygon(lat,lon)
wmpolygon(P)
wmpolygon(wm,___)
wmpolygon(___,Name,Value)
h = wmpolygon(___)

Description

wmpolygon(lat,lon) displays the polygon overlay defined by the vertices in lat and lon on the current web map. If there is no current web map, wmpolygon creates one. wmpolygon centers and scales the map so that all the vector overlays displayed in the web map are visible.

example

wmpolygon(P) displays a polygon overlay based on the vector geographic features stored in P. The overlay contains one polygon feature for each element of P.

example

wmpolygon(wm,___) displays the overlay in the web map specified by the web map handle, wm.

wmpolygon(___,Name,Value) specifies name-value pairs that set additional display properties.

example

h = wmpolygon(___) returns a handle to the overlay.

Examples

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Open Live Script

Load coastline data from a MAT-file.

load coastlines

Display the coastlines as a polygon overlay layer.

wmpolygon(coastlat,coastlon,'OverlayName','Polygon coastlines')

Open Live Script

Define coordinates of rings. For this example, the coordinates define a location centered on the Eiffel Tower.

lat0 = 48.858288;
lon0 = 2.294548;
outerRadius = .01;
innerRadius = .005;
[lat1,lon1] = scircle1(lat0,lon0,outerRadius);
[lat2,lon2] = scircle1(lat0,lon0,innerRadius);
lat2 = flipud(lat2);
lon2 = flipud(lon2);
lat = [lat1; NaN; lat2];
lon = [lon1; NaN; lon2];

Display on a web map.

webmap('worldimagery')
wmpolygon(lat,lon,'EdgeColor','g','FaceColor','c','FaceAlpha',.5)

Open Live Script

Import a shapefile containing state boundary data as a geospatial table.

GT = readgeotable("usastatelo.shp");

Create a colormap from random, muted colors.

colors = polcmap(height(GT));

Display the polygons as an overlay on a web map. Make the polygons semitransparent by using the FaceAlpha name-value argument.

webmap("worldphysicalmap")
wmpolygon(GT,"FaceColor",colors,"FaceAlpha",0.5,"EdgeColor","k", ...
      "EdgeAlpha",0.5,"OverlayName","USA Boundary","FeatureName",GT.Name)

Open Live Script

Large data sets can sometimes be slow to display, making the web map appear to hang. This example shows how to reduce the size of a data set using reducem before calling wmpolygon.

First, load high-resolution vector data into the workspace.

states = shaperead('usastatehi.shp','UseGeoCoords',true);
states = geoshape(states);

Then, reduce the number of points in the latitude and longitude vectors using the reducem function.

for k = 1:length(states)
    [states(k).Latitude, states(k).Longitude] = reducem( ...
        states(k).Latitude', states(k).Longitude');
end

Display state boundaries on the web map. Note that the borders of the reduced polygons may not meet if you zoom in on them.

colors = polcmap(length(states));
webmap('worldphysicalmap')
wmpolygon(states,'FaceColor',colors,'FaceAlpha',.5,'EdgeColor','k', ...
    'EdgeAlpha',.5,'OverlayName','USA Boundary','FeatureName',states.Name)

Input Arguments

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Latitude vertices, specified as matrix in the range [-90, 90].

Data Types: single | double

Longitude of vertices, specified as a matrix.

Data Types: single | double

Geographic features, specified as one of the following:

  • A geospatial table containing geopolyshape objects. For more information about geospatial tables, see Create Geospatial Tables.

  • A geoshape vector with polygon geometry.

Web map, specified as a handle to a web map.1

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: wmpolygon(lat,lon,'Autofit',true)

Overlay visibility, specified as the comma-separated pair consisting of 'Autofit' and the scalar logical or numeric value true (1) or false (0).

  • If true, wmpolygon adjusts the spatial extent of the map to ensure that all the vector overlays on the map are visible.

  • If false, wmpolygon does not adjust the spatial extent of the map when this vector layer is added to the map.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical

Description of feature, specified as the comma-separated pair consisting of 'Description' and a character vector, cell array of character vectors, or a scalar structure.

  • If you specify a character vector, the text defines the content displayed in the description balloon, which appears when you click the feature in the web map. Description elements can be either plain text or marked up with HTML markup.

  • If you specify a cell array, it must be either a scalar or the same length as P, and specifies the description for each polygon.

  • If the value is a structure (attribute specification), wmpolygon displays the attribute fields of P in the balloon, modified according to the specification.

Data Types: char | struct | cell

Name of overlay layer, specified as the comma-separated pair consisting of 'OverlayName' and a character vector. wmpolygon inserts the name in the Layer Manager under the "Overlays" item. The Layer Manager is the tool that appears on the right side of the web map. The default name is 'Polygon Overlay N' where N is the number assigned to this overlay.

Data Types: char

Name of feature, specified as the comma-separated pair consisting of 'FeatureName' and character vector or cell array of character vectors. The name appears in the balloon when you click the feature in the web map. The default value is 'OverlayName: Polygon K', where OverlayName is the name of the overlay and K is the number assigned to the particular polygon.

  • If the value is a character vector, it applies to all features.

  • If the value is a cell array of character vectors, it must be either a scalar or the same length as P.

Data Types: char | cell

Color of polygon faces, specified as the comma-separated pair consisting of 'FaceColor' and one of these options.

  • A color name such as 'red' or a short name such as 'r'.

  • An RGB triplet, which is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1]; for example, [0.4 0.6 0.7].

  • A cell array of color names such as {'red','green','blue'} or {'r','g','b'}.

  • A string vector of color names such as ["red" "green" "blue"] or ["r" "g" "b"].

  • A matrix of RGB triplets, which is a three-column matrix in which each row is an RGB triplet.

The way you specify the color depends on the desired color scheme.

  • To apply the same face color to all polygons in P, specify a single color name or RGB triplet.

  • To apply a different color to each polygon in P, specify a cell array of color names, a string vector of color names, or a matrix of RGB triplets. The number of colors and RGB triplets must match the length of P.

  • To create polygons with no fill, specify 'none'.

This table contains the color names and equivalent RGB triplets for some common colors.

Color NameShort NameRGB TripletAppearance
"red""r"[1 0 0]

Sample of the color red

"green""g"[0 1 0]

Sample of the color green

"blue""b"[0 0 1]

Sample of the color blue

"cyan" "c"[0 1 1]

Sample of the color cyan

"magenta""m"[1 0 1]

Sample of the color magenta

"yellow""y"[1 1 0]

Sample of the color yellow

"black""k"[0 0 0]

Sample of the color black

"white""w"[1 1 1]

Sample of the color white

Data Types: char | string | cell | double

Transparency of polygon faces, specified as the comma-separated pair consisting of 'FaceAlpha' and a numeric scalar or vector in the range [0, 1]. The default value, 1, means that the polygon is fully opaque.

  • If the value is a scalar, it applies to all polygon faces.

  • If the value is a vector, it must be the same length as P.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Color of polygon edges, specified as the comma-separated pair consisting of 'EdgeColor' and one of these options.

  • A color name such as 'red' or a short name such as 'r'.

  • An RGB triplet, which is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1]; for example, [0.4 0.6 0.7].

  • A cell array of color names such as {'red','green','blue'} or {'r','g','b'}.

  • A string vector of color names such as ["red" "green" "blue"] or ["r" "g" "b"].

  • A matrix of RGB triplets, which is a three-column matrix in which each row is an RGB triplet.

The way you specify the color depends on the desired color scheme.

  • To apply the same edge color to all polygons in P, specify a single color name or RGB triplet.

  • To apply a different edge color to each polygon in P, specify a cell array of color names, a string vector of color names, or a matrix of RGB triplets. The number of colors and RGB triplets must match the length of P.

  • To create polygons with no edge color, specify 'none'.

This table contains the color names and equivalent RGB triplets for some common colors.

Color NameShort NameRGB TripletAppearance
"red""r"[1 0 0]

Sample of the color red

"green""g"[0 1 0]

Sample of the color green

"blue""b"[0 0 1]

Sample of the color blue

"cyan" "c"[0 1 1]

Sample of the color cyan

"magenta""m"[1 0 1]

Sample of the color magenta

"yellow""y"[1 1 0]

Sample of the color yellow

"black""k"[0 0 0]

Sample of the color black

"white""w"[1 1 1]

Sample of the color white

Data Types: char | string | cell | double

Transparency of polygon edges, specified the comma-separated pair consisting of 'EdgeAlpha' and as a numeric scalar or vector in the range [0, 1].

  • If the value is a scalar, it applies to all polygon faces.

  • If the value is a vector, it must be the same length as P.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Width of polygon edges, specified as the comma-separated pair consisting of 'LineWidth' and a positive numeric scalar or vector.

  • If the value is a scalar, it applies to all polygon faces.

  • If the value is a vector, it must be the same length as P.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Output Arguments

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Polygon overlay, returned as a handle to the polygon overlay.

Tips

  • When you move the cursor over the polygons you define on an image and click, wmpolygon displays a description balloon and disables panning. If you move the cursor off the polygon, you can still click and pan the image. You can also use the arrow keys to pan the image.

Version History

Introduced in R2016a

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See Also

Functions

Objects

Topics

1 Alignment of boundaries and region labels are a presentation of the feature provided by the data vendors and do not imply endorsement by MathWorks®.