maprefcells

Reference raster cells to map coordinates

Syntax

``R = maprefcells()``
``R = maprefcells(xlimits,ylimits,rasterSize)``
``R = maprefcells(xlimits,ylimits,xcellextent,ycellextent)``
``R = maprefcells(xlimits,ylimits,___,Name,Value)``

Description

````R = maprefcells()` returns a default referencing object for a regular raster of cells in planar (map) coordinates.```

example

````R = maprefcells(xlimits,ylimits,rasterSize)` constructs a referencing object for a raster of cells spanning the specified limits in planar coordinates, with the numbers of rows and columns specified by `rasterSize`.```

example

````R = maprefcells(xlimits,ylimits,xcellextent,ycellextent)` allows the cell extents to be set precisely. If necessary, `maprefcells` adjusts the limits of the raster slightly to ensure an integer number of cells in each dimension.```

example

````R = maprefcells(xlimits,ylimits,___,Name,Value)` allows the directions of the columns and rows to be specified via name-value pairs.```

Examples

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Define latitude and longitude limits and dimensions of the image. The image follows the popular convention in which world x coordinates increase from column to column and world y coordinates decrease from row to row.

```xlimits = [207000 208000]; ylimits = [912500 913000]; rasterSize = [1000 2000]```
```rasterSize = 1×2 1000 2000 ```

Create the referencing object specifying the raster size.

```R = maprefcells(xlimits,ylimits,rasterSize, ... 'ColumnsStartFrom','north')```
```R = MapCellsReference with properties: XWorldLimits: [207000 208000] YWorldLimits: [912500 913000] RasterSize: [1000 2000] RasterInterpretation: 'cells' ColumnsStartFrom: 'north' RowsStartFrom: 'west' CellExtentInWorldX: 1/2 CellExtentInWorldY: 1/2 RasterExtentInWorldX: 1000 RasterExtentInWorldY: 500 XIntrinsicLimits: [0.5 2000.5] YIntrinsicLimits: [0.5 1000.5] TransformationType: 'rectilinear' CoordinateSystemType: 'planar' ProjectedCRS: [] ```

Obtain the same result by specifying the cell extents. For this example, the pixels are 1/2 meter square, referenced to a planar map coordinate system (the "world" system).

```extent = 1/2; R = maprefcells(xlimits,ylimits,extent,extent, ... 'ColumnsStartFrom','north')```
```R = MapCellsReference with properties: XWorldLimits: [207000 208000] YWorldLimits: [912500 913000] RasterSize: [1000 2000] RasterInterpretation: 'cells' ColumnsStartFrom: 'north' RowsStartFrom: 'west' CellExtentInWorldX: 1/2 CellExtentInWorldY: 1/2 RasterExtentInWorldX: 1000 RasterExtentInWorldY: 500 XIntrinsicLimits: [0.5 2000.5] YIntrinsicLimits: [0.5 1000.5] TransformationType: 'rectilinear' CoordinateSystemType: 'planar' ProjectedCRS: [] ```

Input Arguments

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Limits in the x direction, specified as a 1-by-2 numeric vector. The value of `xlimits` determines the `XWorldLimits` property of `R`.

Example: `xlimits = [207000 208000];`

Limits in the y direction, specified as a 1-by-2 numeric vector. The value of `ylimits` determines the `YWorldLimits` property of `R`.

Example: `ylimits = [912500 913000];`

Size of the raster, specified as a 1-by-2 numeric vector.

Example: `rasterSize = [180 360];`

Width of cells, specified as a numeric scalar. The value of `xcellextent` determines the `CellExtentInWorldX` property of `R`.

Example: `xcellextent = 1.5`

Height of cells, specified as a numeric scalar. The value of `ycellextent` determines the `CellExtentInWorldY` property of `R`.

Example: `ycellextent = 1.5`

Name-Value Arguments

Specify optional pairs of arguments as `Name1=Value1,...,NameN=ValueN`, where `Name` is the argument name and `Value` is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose `Name` in quotes.

Example: `R = maprefcells(latlim,lonlim,rasterSize,'ColumnsStartFrom','north')`

Edge from which column indexing starts, specified as `'north'` or `'south'`.

Example: ` R = maprefcells(latlim,lonlim,rasterSize,'ColumnsStartFrom','north')`

Data Types: `char` | `string`

Edge from which column indexing starts, specified as `'west'` or `'east'`.

Example: ` R = maprefcells(latlim,lonlim,rasterSize,'RowsStartFrom','east')`

Data Types: `char` | `string`

Output Arguments

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Object that references raster cells to map coordinates, returned as a `MapCellsReference` raster reference object.

Version History

Introduced in R2015b