aoiquad
Syntax
Description
Numeric Data
defines an area of
interest (AOI) for the specified geographic coordinates by creating a
quadrangle that bounds the coordinates.aoi
= aoiquad(lat
,lon
)
Examples
Define Quadrangular AOI from Latitude-Longitude Limits
Specify the latitude and longitude limits for a region surrounding the island of Kyushu, Japan. Specify the geographic CRS as the World Geodetic System of 1984, which has the EPSG code 4326
.
latlim = [31 34]; lonlim = [129 132.5]; gcrs = geocrs(4326);
Create a quadrangular AOI from the limits. When you pass geographic coordinates to the aoiquad
function, the function represents the AOI using a scalar polygon shape in geographic coordinates.
aoi = aoiquad(latlim,lonlim,gcrs)
aoi = geopolyshape with properties: NumRegions: 1 NumHoles: 0 Geometry: "polygon" CoordinateSystemType: "geographic" GeographicCRS: [1×1 geocrs]
View satellite imagery for the region surrounding the AOI by plotting the AOI with no face or edge color.
geobasemap satellite geoplot(aoi,FaceColor="none",EdgeColor="none")
Define Rectangular AOI from Projected Coordinates
Specify the projected coordinates for several places in Boston. Specify the projected CRS for the points as NAD83 / Massachusetts Mainland, which has the EPSG code 26986
.
x = [234028 233569 235739 236266 234685 236536 234591 237114 235741 236548]; y = [900038 900190 901126 900974 901429 901901 901892 900670 900725 899587]; pcrs = projcrs(26986);
Create a rectangular AOI from the coordinates and the projected CRS. When you pass projected coordinates to the aoiquad
function, the function represents the AOI using a scalar polygon shape in projected coordinates.
aoi = aoiquad(x,y,pcrs)
aoi = mappolyshape with properties: NumRegions: 1 NumHoles: 0 Geometry: "polygon" CoordinateSystemType: "planar" ProjectedCRS: [1×1 projcrs]
Display the AOI on a map.
geobasemap streets
geoplot(aoi)
Define Rectangular AOI from Geospatial Table
Read road data for an area in Concord, MA as a geospatial table. The table represents the roads using line shapes in projected coordinates.
GT = readgeotable("concord_roads.shp");
GT.Shape
ans=609×1 maplineshape array with properties:
NumParts: [609×1 double]
Geometry: "line"
CoordinateSystemType: "planar"
ProjectedCRS: [1×1 projcrs]
⋮
Create a rectangular AOI from the shapes in the geospatial table. When you pass data in projected coordinates to the aoiquad
function, the function represents the AOI using a scalar polygon shape in projected coordinates.
aoi = aoiquad(GT)
aoi = mappolyshape with properties: NumRegions: 1 NumHoles: 0 Geometry: "polygon" CoordinateSystemType: "planar" ProjectedCRS: [1×1 projcrs]
Display the road data and the boundary of the AOI on a map. Display the boundary of the AOI using a thick, dashed line.
geoplot(GT) hold on geoplot(aoi,LineWidth=2,LineStyle="--",FaceColor="none")
Define Geographic AOI from Geocoded Placename
Create a geospatial table by geocoding the states of Kansas and Oklahoma. The table represents the states using polygon shapes in geographic coordinates.
GT = geocode(["Kansas","Oklahoma"],"state"); GT.Shape
ans=2×1 geopolyshape array with properties:
NumRegions: [2×1 double]
NumHoles: [2×1 double]
Geometry: "polygon"
CoordinateSystemType: "geographic"
GeographicCRS: [1×1 geocrs]
Create a quadrangular AOI from the shapes in the geospatial table. When you pass data in geographic coordinates to the aoiquad
function, the function represents the AOI using a scalar polygon shape in geographic coordinates.
aoi = aoiquad(GT)
aoi = geopolyshape with properties: NumRegions: 1 NumHoles: 0 Geometry: "polygon" CoordinateSystemType: "geographic" GeographicCRS: [1×1 geocrs]
Display the states and the boundary of the AOI on a map. Display the boundary of the AOI using a thick, dashed line.
geobasemap colorterrain geoplot(GT) hold on geoplot(aoi,LineWidth=2,LineStyle="--",FaceColor="none")
Define Quadrangular AOI from Shape Object
Read the geographic coordinates of European capitals into the workspace. Create a point shape object from the coordinates. Specify the geographic CRS as the World Geodetic System of 1984, which has the EPSG code 4326
.
[lat,lon] = readvars("european_capitals.txt");
shape = geopointshape(lat,lon);
shape.GeographicCRS = geocrs(4326);
Create a quadrangular AOI from the shapes. When you pass data in geographic coordinates to the aoiquad
function, the function represents the AOI using a scalar polygon shape in geographic coordinates.
aoi = aoiquad(shape);
Create a map using the latitude and longitude limits of the AOI. Note that, to maintain the aspect ratio of the map, the geolimits
function typically uses wider limits than the limits you specify.
[latlim,lonlim] = bounds(aoi); geolimits(latlim,lonlim)
Define Quadrangular AOI From Raster Data
Get the AOI for a raster data file. Then, display the AOI on a map. Displaying the AOI for a raster data file enables you to view the footprint of the file.
Get information about a raster data file by creating a RasterInfo
object. Extract the spatial reference from the object. The spatial reference indicates that the raster is a grid of rectangular cells referenced to projected xy-coordinates.
info = georasterinfo("MountDartmouth-ft.grd");
R = info.RasterReference
R = MapCellsReference with properties: XWorldLimits: [300390 310770] YWorldLimits: [4902150 4916340] RasterSize: [473 346] RasterInterpretation: 'cells' ColumnsStartFrom: 'north' RowsStartFrom: 'west' CellExtentInWorldX: 30 CellExtentInWorldY: 30 RasterExtentInWorldX: 10380 RasterExtentInWorldY: 14190 XIntrinsicLimits: [0.5 346.5] YIntrinsicLimits: [0.5 473.5] TransformationType: 'rectilinear' CoordinateSystemType: 'planar' ProjectedCRS: [1×1 projcrs]
Create a rectangular AOI from the spatial reference. When you pass data in projected coordinates to the aoiquad
function, the function represents the AOI using a scalar polygon shape in projected coordinates.
aoi = aoiquad(R)
aoi = mappolyshape with properties: NumRegions: 1 NumHoles: 0 Geometry: "polygon" CoordinateSystemType: "planar" ProjectedCRS: [1×1 projcrs]
Note that the bounds of the AOI match the XWorldLimits
and YWorldLimits
properties of the spatial reference.
[xlimits,ylimits] = bounds(aoi); isequal(xlimits,R.XWorldLimits) && isequal(ylimits,R.YWorldLimits)
ans = logical
1
Display the AOI on a map. The AOI represents the footprint of the raster data file.
geobasemap topographic
geoplot(aoi)
Export Quadrangular AOI to Shapefile
Export the footprint of a raster data file to a shapefile.
Get information about a DTED file by creating a RasterInfo
object. Create an AOI from the spatial reference that is stored in the RasterInfo
object.
info = georasterinfo("n40_w106_3arc_v2.dt1");
R = info.RasterReference;
aoi = aoiquad(R);
Create a geospatial table from the AOI. Then, export the geospatial table to a shapefile by using the shapewrite
function.
aoiGT = table(aoi,VariableName="Shape"); filename = "n40_w106_footprint.shp"; shapewrite(aoiGT,filename)
Read the shapefile into the workspace, and view the AOI.
GT = readgeotable(filename);
geobasemap topographic
geoplot(GT)
Input Arguments
lat
— Latitude coordinates in degrees
numeric array with elements in range [–90, 90]
Latitude coordinates in degrees, specified as a numeric array with elements in
the range [–90, 90]. The sizes of lat
and
lon
must match.
If lat
and lon
are scalar, then the
function creates the AOI by calculating a small buffer around the point.
lon
— Longitude coordinates in degrees
numeric array
Longitude coordinates in degrees, specified as a numeric array. The sizes of
lat
and lon
must match.
If lat
and lon
are scalar, then the
function creates the AOI by calculating a small buffer around the point.
gcrs
— Geographic CRS of latitude and longitude coordinates
geocrs
object
Geographic CRS of the latitude and longitude coordinates, specified as a
geocrs
object.
x
— x-coordinates
numeric array
x-coordinates, specified as a numeric array. The sizes of
x
and y
must match.
If x
and y
are scalar, then the
function creates the AOI by calculating a small buffer around the point.
y
— y-coordinates
numeric array
y-coordinates, specified as a numeric array. The sizes of
x
and y
must match.
If x
and y
are scalar, then the
function creates the AOI by calculating a small buffer around the point.
pcrs
— Projected CRS for xy-coordinates
projcrs
object
Projected CRS for the xy-coordinates, specified as a projcrs
object.
GT
— Geospatial table
geospatial table
Geospatial table. A geospatial table is a table
or timetable
object with a
Shape
variable that contains point, line, or polygon shapes.
For more information about geospatial tables, see Create Geospatial Tables.
The ProjectedCRS
properties of mappointshape
, maplineshape
, and mappolyshape
objects within the Shape
variable
must not be empty.
shape
— Point, line, or polygon shapes
vector of geopointshape
, geolineshape
, or
geopolyshape
objects | vector of mappointshape
, maplineshape
, or
mappolyshape
objects
Point, line, or polygon shapes, specified as one of these options:
A vector of
geopointshape
,geolineshape
, orgeopolyshape
objects — Point, line, or polygon shapes in geographic coordinates.A vector of
mappointshape
,maplineshape
, ormappolyshape
objects — Point, line, or polygon shapes in projected coordinates. TheProjectedCRS
properties of the shapes must not be empty.
For each option, you can include a combination of point, line, and polygon shapes. You can also specify this argument as a scalar point, line, or polygon shape.
R
— Spatial reference
array of GeographicCellsReference
objects | array of GeographicPostingsReference
objects | array of MapCellsReference
objects | array of MapPostingsReference
objects
Spatial reference, specified one of these options:
An array of
GeographicCellsReference
objects — Spatial reference for a grid of quadrangular cells in geographic coordinates.An array of
GeographicPostingsReference
objects — Spatial reference for a grid of posting point samples in geographic coordinates.An array of
MapCellsReference
objects — Spatial reference for a grid of quadrangular cells in projected coordinates.An array of
MapPostingsReference
objects — Spatial reference for a grid of posting point samples in projected coordinates.
You can also specify this argument as a scalar object.
The ProjectedCRS
properties of
MapCellsReference
and MapPostingsReference
objects must not be empty.
Output Arguments
aoi
— Quadrangular or rectangular AOI
scalar geopolyshape
object | scalar mappolyshape
object
Quadrangular or rectangular AOI, returned as one of these options:
A scalar
geopolyshape
object, when you specify the input using geographic coordinates. The boundaries of the AOI follow linear paths.A scalar
mappolyshape
object, when you specify the input using projected coordinates.
The aoiquad
function creates the boundary of the AOI by
linearly interpolating points between the corners of the AOI.
More About
Area of Interest
An area of interest (AOI) defines a focus
area for geospatial analysis and visualization. Mapping Toolbox™ represents AOIs using polygon shape objects. A scalar geopolyshape
object represents an AOI in geographic coordinates, and a scalar mappolyshape
object represents an AOI in projected coordinates.
Version History
Introduced in R2024b
See Also
Functions
Objects
Topics
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