# worldToDiscrete

Transform planar world to discrete coordinates

## Syntax

``[I,J] = worldToDiscrete(R,xWorld,yWorld)``

## Description

example

````[I,J] = worldToDiscrete(R,xWorld,yWorld)` returns the indices corresponding to world coordinates `xWorld` and `yWorld` in map 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 a GeoTIFF image [1] of Boston as an array and a `MapCellsReference` object. Find the indices of the cell containing data with world $\mathit{x}$- and $\mathit{y}$-coordinates of `776500` and `2956600` survey feet, respectively.

```[Z,R] = readgeoraster('boston.tif'); [I,J] = worldToDiscrete(R,776500,2956600)```
```I = 1212 ```
```J = 3714 ```

The result means that the cell center closest to the world coordinates is in row 1212 and column 3714 of the array.

[1] The data used in this example includes material copyrighted by GeoEye, all rights reserved.

## Input Arguments

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x-coordinates in the world coordinate system, specified as a numeric array.

Data Types: `single` | `double`

y-coordinates in the world coordinate system, specified as a numeric array. `yWorld` is the same size as `xWorld`.

Data Types: `single` | `double`

## Output Arguments

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World x-coordinate indices, returned as an array of integers. `I` is the same size as `xWorld`.

For an m-by-n raster, 1 ≤ `I`m, except for points (`xWorld`(k), `yWorld`(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`

World y-coordinate indices, returned as an array of integers. `J` is the same size as `yWorld`.

For an m-by-n raster, 1 ≤ `I`m, except for points (`xWorld`(k), `yWorld`(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