geographicGrid
Description
[
,
where lat
,lon
] = geographicGrid(R
,gridOption
)gridOption
is 'gridvectors'
, returns
lat
and lon
as vectors. The coordinates of
raster element (i,j)
are (lat(i),lon(j))
. The default
for gridOption
is 'fullgrid'
, which returns
lat
and lon
as 2-D arrays.
Examples
Find Coordinates of Raster Elements
Import elevation data [1] for an area around South Boulder Peak in Colorado as an array and a geographic postings reference object. Find the coordinates of each element in the array.
[Z,R] = readgeoraster('n39_w106_3arc_v2.dt1');
[lat,lon] = geographicGrid(R);
Create a map with latitude and longitude limits that match the limits of the data. Display the data using an appropriate colormap.
usamap(R.LatitudeLimits,R.LongitudeLimits) surfm(lat,lon,Z) demcmap(Z)
[1] The elevation data used in this example is courtesy of the U.S. Geological Survey.
Get Vectors Instead of Arrays
Create a geographic cells reference object for a 3-by-4 raster with latitude values in the range [0, 30] degrees and longitude values in the range [-20, 20] degrees. Get the coordinates of the raster elements and return them as row vectors.
R = georefcells([0 30],[-20 20],[3 4]);
[lat,lon] = geographicGrid(R,'gridvectors')
lat = 1×3
5 15 25
lon = 1×4
-15 -5 5 15
If you do not specify the second argument as 'gridvectors'
, then the geographicGrid
function returns 2-D arrays by default.
[latFull,lonFull] = geographicGrid(R)
latFull = 3×4
5 5 5 5
15 15 15 15
25 25 25 25
lonFull = 3×4
-15 -5 5 15
-15 -5 5 15
-15 -5 5 15
Input Arguments
R
— Spatial reference
GeographicCellsReference
object | GeographicPostingsReference
object
Spatial reference, specified as a GeographicCellsReference
or GeographicPostingsReference
object.
If R
is a GeographicCellsReference
object,
then lat
and lon
are cell centers. If
R
is a GeographicPostingsReference
object, then
lat
and lon
are posting points.
gridOption
— Grid option
'fullgrid'
(default) | 'gridvectors'
Grid option, specified as one of these values:
'fullgrid'
— Returnlat
andlon
as 2-D arrays, where each column oflat
is identical and each row oflon
is identical. This is the default behavior.'gridvectors'
— Returnlat
andlon
as row vectors. Use this option when you want to reduce memory usage and when 2-D arrays are unnecessary, such as when plotting large data sets with thesurfm
function.
This table shows the difference between 'fullgrid'
and
'gridvectors'
.
'fullgrid' | 'gridvectors' |
---|---|
R = georefcells([0 30],[-20 20],[3 4]); [lat,lon] = geographicGrid(R) lat = 5 5 5 5 15 15 15 15 25 25 25 25 lon = -15 -5 5 15 -15 -5 5 15 -15 -5 5 15 |
R = georefcells([0 30],[-20 20],[3 4]);
[lat,lon] = geographicGrid(R,'gridvectors') lat = 5 15 25 lon = -15 -5 5 15 |
Data Types: char
| string
Output Arguments
lat
— Latitudes
2-D array (default) | row vector
Latitudes, returned as a 2-D array or a row vector. By default,
lat
is a 2-D array. To return lat
as a row
vector, specify gridOption
as
'gridvectors'
.
By default, and when gridOption
is
'fullgrid'
, the sizes of lat
and
lon
each equal the RasterSize
property of
R
. When gridOption
is
'gridvectors'
, the lengths of lat
and
lon
equal the first and second elements of the
RasterSize
property of R
,
respectively.
lon
— Longitudes
2-D array (default) | row vector
Longitudes, returned as a 2-D array or a row vector. By default,
lon
is a 2-D array. To return lon
as a row
vector, specify gridOption
as
'gridvectors'
.
By default, and when gridOption
is
'fullgrid'
, the sizes of lat
and
lon
each equal the RasterSize
property of
R
. When gridOption
is
'gridvectors'
, the lengths of lat
and
lon
equal the first and second elements of the
RasterSize
property of R
,
respectively.
Version History
Introduced in R2021a
See Also
Functions
Objects
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