WMSMapRequest class -

Web Map Service map request object

Description

A WMSMapRequest object contains a request to a WMS server to obtain a map, which represents geographic information. The WMS server renders the map as a color or grayscale image. The object contains properties that you can set to control the geographic extent, rendering, or size of the requested map.

Construction

mapRequest = WMSMapRequest(layer) constructs a WMSMapRequest object. The WMSLayer array layer contains only one unique ServerURL. The WMSMapRequest class updates the properties of layer, if necessary.

mapRequest = WMSMapRequest(layer, server) constructs a WMSMapRequest object. layer is a WMSLayer object, and server is a scalar WebMapServer object. The ServerURL property of layer must match the ServerURL property of server. The server object updates layer properties.

Properties

`Server`	Initialized to the `Server` input, if supplied to the constructor; otherwise constructed using the `ServerURL` of `Layer`. Data Type: scalar `WebMapServer` object
`Layer`	Initialized to the `layer` input supplied to the constructor. The `Layer` property contains one unique `ServerURL`. The `Server` property updates the properties of `Layer` when the property is set. The `ServerURL` property of `Layer` must match the `ServerURL` property of `Server`. Data Type: `WMSLayer` array
`CoordRefSysCode`	Specifies the coordinate reference system code. Its default value is `'EPSG:4326'`. If `'EPSG:4326'` is not found in `Layer.CoordRefSysCodes`, then the `CoordRefSysCode` value is set from the first `CoordRefSysCode` found in the `Layer.Details.BoundingBox` structure array. When `CoordRefSysCode` is set to `'EPSG:4326'` or `'CRS:84'`, the `XLim` and `YLim` properties are set to `[]` and the `Latlim` and `Lonlim` properties are set to the geographic extent defined by the `Layer` array. When `CoordRefSysCode` is set to a value other than `'EPSG:4326'` or `'CRS:84'`, then the `XLim` and `YLim` properties are set from the values found in the `Layer.Details.BoundingBox` structure and the `Latlim` and `Lonlim` properties are set to `[]`. Automatic projections are not supported. (Automatic projections begin with the string `'AUTO'`.) Data Type: string Default: `'EPSG:4326'`
`RasterRef`	References the raster map to an intrinsic coordinate system. Data Type: 3-by-2 matrix
`Latlim`	Contains the southern and northern latitudinal limits of the request in units of degrees. The limits must be ascending. Data Type: two-element vector Default: Limits that span all latitudinal limits found in the `Layer.Latlim` property
`Lonlim`	Contains the western and eastern longitudinal limits of the request in units of degrees. The limits must be ascending and in the range [-180, 180] or [0 360]. Data Type: two-element vector Default: Limits that span all longitudinal limits in the `Layer.Lonlim` property
`XLim`	Contains the western and eastern limits of the request in units specified by the coordinate reference system. The limits must be ascending. You can set `XLim` only if you set `CoordRefSysCode` to a value other than `EPSG:4326`. Data Type: two-element vector Default: `[]`
`YLim`	Contains the southern and northern limits of the request in units specified by the coordinate reference system. The limits must be ascending. You can set `YLim` only if you set `CoordRefSysCode` to a value other than `EPSG:4326`. Data Type: two-element vector Default: `[]`
`ImageHeight`	Specifies the height in pixels for the requested raster map. The property `MaximumHeight` defines the maximum value for `ImageHeight`. The `WMSMapRequest` class initializes the `ImageHeight` property to either 512 or to an integer value that best preserves the aspect ratio of the coordinate limits, without changing the coordinate limits. Data Type: scalar, positive integer
`ImageWidth`	Specifies the width in pixels for the requested raster map. The property `MaximumWidth` defines the maximum value for `ImageWidth`. The `WMSMapRequest` class initializes the `ImageWidth` property to either 512 or to an integer value that best preserves the aspect ratio of the coordinate limits, without changing the coordinate limits. Data Type: scalar, positive integer
`Maximum Height`	Contains the maximum height in pixels for the requested map. Cannot be set. The value of `MaximumHeight` is 8192. Data Type: `double`
`Maximum Width`	Contains the maximum width in pixels for the requested map. Cannot be set. The value of `MaximumWidth` is 8192. Data Type: `double`
`Elevation`	Gives the elevation extent of the requested map. When you set the property, `'elevation'` must be the value of the `Layer.Details.Dimension.Name` field. Data Type: string Default: `''`
`Time`	Specifies the time extent of the requested map. See the `WMSMapRequest.Time` reference page for more information. Data Type: string or double Default: `''`
`SampleDimension`	Contains the name of a sample dimension (other than `'time'` or `'elevation'`) and its value. `SampleDimension{1}` must be the value of the `Layer.Details.Dimension.Name` field. Data Type: two-element cell array of strings
`Transparent`	Specifies whether the map background is transparent. When you set `Transparent` to `true`, the server sets all pixels not representing features or data values in that layer to a transparent value, producing a composite map. When you set `Transparent` to `false`, the server sets all non-data pixels to the value of the background color. Data Type: logical scalar Default: `false`
`BackgroundColor`	Specifies the color of the background (non-data) pixels of the map. The values range from 0 to 255. The default value, `[255,255,255]`, specifies the background color as white. You can set `BackgroundColor` using `non-uint8` numeric values, but they are cast and stored as `uint8`. Data Type: three-element vector of `uint8` values
`StyleName`	Specifies the style to use when rendering the image. The `StyleName` must be a valid entry in the `Layer.Details.Style.Name` field. (The cell array of strings contains the same number of elements as does `Layer`.) Data Type: string or cell array of strings Default: `{}`
`ImageFormat`	Specifies the desired image format used to render the map as an image. If set, the format must match an entry in the `Layer.Details.ImageFormats` cell array and an entry in the `ImageRenderFormats` property. If not set, the format defaults to a value in the `ImageRenderFormats` property. Data Type: string
`ImageRenderFormats`	Contains the preferred image rendering formats when `Transparent` is set to `false`. The first entry is the most preferred image format. If the preferred format is not stored in the `Layer` property, then the next format from the list is selected, until a format is found. The `ImageRenderFormats` array is not used if the `ImageFormat` property is set. The `ImageRenderFormats` property cannot be set. Data Type: cell array
`ImageTransparentFormats`	Contains the preferred image rendering formats when `Transparent` is set to `true`. When `Transparent` is set to `true`, the `ImageFormat` property is set to the first entry in the `ImageTransparentFormats` list, if it is stored in the `Layer` property. Otherwise, the list is searched for the next element, until a match is found. If a transparent image format is not found in the list, or if the `ImageFormat` property is set to a non-default value, then `ImageFormat` is unchanged. The `ImageTransparentFormats` property cannot be set. Data Type: cell array
`ServerURL`	Contains the server URL for the WMS `GetMap` request. In general, `ServerURL` matches the `ServerURL` of the `Layer`. However, some WMS servers, such as the Microsoft TerraServer, require a different URL for `GetMap` requests than for WMS `GetCapabilities` requests. Data Type: string Default: `Layer(1).ServerURL`
`RequestURL`	Contains the URL for the WMS `GetMap` request. It is composed of the `ServerURL` with additional WMS parameter/value pairs. This property cannot be set. Data Type: string

Methods

boundImageSize

Bound size of raster map

Examples

Read a global, half-degree resolution sea surface temperature map for the month of November 2009. The map, from the AMSR-E sensor on NASA's Aqua satellite, uses data provided by NASA's Earth Observations (NEO) WMS server.

sst =  wmsfind('AMSRE_SST_M');
server = WebMapServer(sst.ServerURL);
mapRequest = WMSMapRequest(sst, server);
timeRequest = '2009-11-01';
mapRequest.Time = timeRequest;
samplesPerInterval = .5;
mapRequest.ImageHeight = ...
   round(abs(diff(sst.Latlim))/samplesPerInterval);
mapRequest.ImageWidth = ...
   round(abs(diff(sst.Lonlim))/samplesPerInterval);
mapRequest.ImageFormat = 'image/png';
sstImage = server.getMap(mapRequest.RequestURL);

The legend for the layer can be obtained via the OnlineResource URL field in the LegendURL structure. The legend shows that the temperature ranges from -2 to 35 degrees Celsius. The WMSMapRequest object updates the layer information from the server.

[legend, cmap] = imread...
    (mapRequest.Layer.Details.Style(1).LegendURL.OnlineResource);
if isempty(cmap) 
   legendImg = legend; 
else 
   legendImg = ind2rgb(legend, cmap); 
end

Display the temperature map and legend.

figure('Color','white')
worldmap world
setm(gca, 'MlabelParallel', -90, 'MlabelLocation', 90)
geoshow(sstImage, mapRequest.RasterRef);
title({mapRequest.Layer.LayerTitle, timeRequest}, ...
   'Interpreter', 'none', 'FontWeight', 'bold')

figurePosition = get(gcf, 'position');
centerWidth = figurePosition(3)/2;
left = centerWidth - size(legendImg,2)/2;
bottom = 30;
width  = size(legendImg,2);
height = size(legendImg,1);
axes('Units', 'pixels', 'Position', [left bottom width height])
image(legendImg)
axis off

Additional abstract information for this layer can be obtained from the MetadataURL field.

filename = [tempname '.xml'];
urlwrite(mapRequest.Layer.Details.MetadataURL, filename);
xml = xmlread(filename);
delete(filename);
xml.getElementsByTagName('abstract').item(0).getTextContent

The output appears as shown.

ans =
 
<p>Sea surface temperature is the temperature of the top 
millimeter of the ocean's surface. Sea surface temperatures 
influence weather, including hurricanes, as well as plant 
and animal life in the ocean. Like Earth's land surface, 
sea surface temperatures are warmer near the equator and 
colder near the poles. Currents like giant rivers move 
warm and cold water around the world's oceans. Some of 
these currents flow on the surface, and they are obvious 
in sea surface temperature images. Special microwave 
technology allows the AMSR-E sensor on NASA's Aqua satellite
to measure sea surface temperatures through clouds, something
no satellite sensor before it was able to do across the 
whole globe.</p>

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