geographicToDiscrete

Transform geographic to discrete coordinates

Syntax

``[I,J] = geographicToDiscrete(R,lat,lon)``

Description

example

````[I,J] = geographicToDiscrete(R,lat,lon)` returns the indices corresponding to geographic coordinates `lat` and `lon` in geographic raster `R`. If `R.RasterInterpretation` is: `'cells'`, then `I` and `J` are the row and column subscripts of the raster cells (or image pixels)`'postings'`, then `I` and `J` refer to the nearest sample point (posting) ```

Examples

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Import elevation data [1] for a region in Colorado as an array and a `GeographicPostingsReference` object. Find the indices of the posting point nearest to the latitude and longitude of South Boulder Peak, which are `39.9539` and `-105.2992` degrees, respectively.

```[Z,R] = readgeoraster('n39_w106_3arc_v2.dt1'); [I,J] = geographicToDiscrete(R,39.9539,-105.2992)```
```I = 56 ```
```J = 842 ```

The result means that the posting point closest to the geographic coordinates is in row 56 and column 842 of the array.

[1] The elevation data used in this example is from the U.S. Geological Survey.

Input Arguments

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Latitude coordinates, specified as a numeric array.

Data Types: `single` | `double`

Longitude coordinates, specified as a numeric array. `lon` is the same size as `lat`.

Data Types: `single` | `double`

Output Arguments

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Longitude indices, returned as an array of integers. `I` is the same size as `lat`.

For an m-by-n raster, 1 ≤ `I`m, except for points ( `lat`(k), `lat`(k) ) that fall outside the bounds of the raster as defined by the function `contains`. In this case `I`(k) and `J`(k) are `NaN`.

Data Types: `double`

Latitude indices, returned as an array of integers. `J` is the same size as `lat`.

For an m-by-n raster, 1 ≤ `J`nexcept for points ( `lat`(k), `lat`(k) ) that fall outside the bounds of the raster as defined by the function `contains`. In this case `I`(k) and `J`(k) are `NaN`.

Data Types: `double`

Version History

Introduced in R2013b