maptrims - Trim regular data grid to latitude-longitude quadrangle

Syntax

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

Description

[Z_trimmed] = maptrims(Z,R,latlim,lonlim) trims a regular data grid Z to the region specified by latlim and lonlim. R is either a 1-by-3 vector containing elements:

[cells/degree northern_latitude_limit western_longitude_limit]

or a 3-by-2 referencing matrix that transforms raster row and column indices to/from geographic coordinates according to:

[lon lat] = [row col 1] * R

If 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 output grid Z_trimmed has the same sample size as the input.

[Z_trimmed] = maptrims(Z,R,latlim,lonlim,cellDensity) uses 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 or matrix for the trimmed data grid. If R is a referencing vector, then R_trimmed is a referencing vector. Likewise, if R is a referencing matrix, then R_trimmed is a referencing matrix.

Examples

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.

maptrims - Trim regular data grid to latitude-longitude quadrangle

Syntax

Description

Examples

See Also

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