Note: This page has been translated by MathWorks. Please click here

To view all translated materials including this page, select Japan from the country navigator on the bottom of this page.

To view all translated materials including this page, select Japan from the country navigator on the bottom of this page.

Trim regular data grid to latitude-longitude quadrangle

`[Z_trimmed] = maptrims(Z,R,latlim,lonlim)`

[Z_trimmed] = maptrims(Z,R,latlim,lonlim,cellDensity)

[Z_trimmed, R_trimmed] = maptrims(...)

`[Z_trimmed] = maptrims(Z,R,latlim,lonlim)`

trims
a regular data grid `Z`

to the region specified by `latlim`

and `lonlim`

.
By default, the output grid `Z_trimmed`

has the same
sample size as the input. `R`

can be a geographic
raster reference object, a referencing vector, or a referencing matrix.
If `R`

is a geographic raster reference object, its `RasterSize`

property
must be consistent with `size(Z)`

and its `RasterInterpretation`

must
be `'cells'`

.

If `R`

is a referencing vector, it must be
a 1-by-3 vector with elements:

[cells/degree northern_latitude_limit western_longitude_limit]

`R`

is
a referencing matrix, it must be 3-by-2 and transform raster row and
column indices to/from geographic coordinates according to:
[lon lat] = [row col 1] * R

`R`

is
a referencing matrix, it must define a (non-rotational, non-skewed)
relationship in which each column of the data grid falls along a meridian
and each row falls along a parallel. `latlim`

and `lonlim`

are
two-element vectors, defining the latitude and longitude limits, respectively.
The `latlim`

vector has the form:[southern_limit northern_limit]

Likewise, the `lonlim`

vector has the form:

[western_limit eastern_limit]

When an individual value in `latlim`

or `lonlim`

corresponds
to a parallel or meridian that runs precisely along cell boundaries,
the output grid will extend all the way to that limit. But if a limiting
parallel or meridian cuts through a column or row of input cells,
then the limit will be adjusted inward. In other words, the requested
limits will be truncated as necessary to avoid partial cells.

`[Z_trimmed] = maptrims(Z,R,latlim,lonlim,cellDensity)`

uses
the scalar `cellDensity`

to reduce the size of the
output. If `R`

is a referencing vector, then `R(1)`

must
be evenly divisible by `cellDensity`

. If `R`

is
a referencing matrix, then the inverse of each element in the first
two rows (containing "`deltaLat`

" and "`deltaLon`

")
must be evenly divisible by `cellDensity`

.

`[Z_trimmed, R_trimmed] = maptrims(...)`

returns
a referencing vector, matrix, or object for the trimmed data grid.
If `R`

is a referencing vector, then `R_trimmed`

is
a referencing vector. If `R`

is a referencing matrix,
then `R_trimmed`

is a referencing matrix. If `R`

is
a geographic raster reference object, then `R_trimmed`

is
either a geographic raster reference object (when `Z_trimmed`

is
non-empty) or `[]`

(when `Z_trimmed`

is
empty).

load topo [subgrid,subrefvec] = maptrims(topo,topolegend,... [80.25 85.3],[165.2 170.7]) subgrid = -2826 -2810 -2802 -2793 -2915 -2913 -2905 -2884 -3192 -3186 -3165 -3122 -3399 -3324 -3273 -3214 subrefvec = 1 85 166

The upper left corner of the grid might differ slightly from
that of the requested region. `maptrims`

uses the
corner coordinates of the first cell inside the limits.

Was this topic helpful?