worldfilewrite

Write world file from raster reference object

Syntax

worldfilewrite(R,filename)

Description

worldfilewrite(R,filename) writes a world file from the specified raster reference object.

Examples

Write World File from Reference Object

Read an image as an array by using the imread function.

A = imread("boston_common.jpg");

Spatially reference the image by creating a map cells reference object. For more information about how to spatially reference an image, see Spatially Reference Imported Rasters.

xlimits = [235150 236150];
ylimits = [900100 901100];
R = maprefcells(xlimits,ylimits,size(A),ColumnsStartFrom="north");

Write the reference object to a world file. Get the filename for the world file by using the getworldfilename function.

filename = getworldfilename("boston_common.jpg");
worldfilewrite(R,filename)

Verify the result. Read the world file into the workspace as a new reference object. Then, display the georeferenced image on a map.

newR = worldfileread(filename,"planar",size(A));
mapshow(A,newR)

The data used in this example is derived from data provided by MassGIS (Bureau of Geographic Information). See the file boston_common.txt for more details.

Input Arguments

R — Raster reference

GeographicCellsReference object | GeographicPostingsReference object | MapCellsReference object | MapPostingsReference object

Raster reference, specified as a GeographicCellsReference, GeographicPostingsReference, MapCellsReference, or MapPostingsReference object.

filename — Filename

string scalar | character vector

Filename, specified as a string scalar or a character vector. You can get the name of a world file from the name of an image file by using the getworldfilename function. Common world file extensions include .tfw, .jgw, and .pgw.

The way you specify filename depends on the location you are writing to.

• To write to the current folder, specify the name of the file, such as "myWorldfile.tfw".

• To write to a folder different from the current folder, specify the full or relative path name, such as "C:\myfolder\myWorldfile.jgw" or "dataDir\myWorldfile.pgw".

If filename is the name of an existing file, then worldfilewrite overwrites the file. If filename does not already exist, then worldfilewrite creates the file.

Data Types: char | string

Version History

Introduced before R2006a

R2024b: worldfilewrite does not accept referencing matrices as input

The worldfilewrite function does not accept referencing matrices as input. Use a geographic raster reference object (specified as a GeographicCellsReference or GeographicPostingsReference object) or a map raster reference object (specified as a MapCellsReference or MapPostingsReference object) as input instead. Reference objects have several advantages over referencing matrices.

• Unlike referencing matrices, reference objects have properties that document the size of the associated raster, its limits, and the direction of its rows and columns.

• You can manipulate the limits of rasters associated with reference objects using the geocrop or mapcrop function.

• You can manipulate the size and resolution of rasters associated with reference objects using the georesize or mapresize function.

Depending on whether the referencing matrix is in geographic or planar coordinates, there are different ways to update your code.

Geographic Coordinates

If the referencing matrix is in geographic coordinates, create a geographic reference object.

• Create a geographic reference object for a raster of cells by using the georefcells function.

• Create a geographic reference object for a raster of regularly posted samples by using the georefpostings function.

• Convert from a referencing matrix to a geographic reference object by using the refmatToGeoRasterReference function.

Once you have created a geographic reference object, replace uses of the referencing matrix in your code with the geographic reference object.

Planar Map Coordinates

If the referencing matrix is in planar map coordinates, create a map reference object.

• Create a map reference object for a raster of cells by using the maprefcells function.

• Create a map reference object or for a raster of regularly posted samples by using the maprefpostings function.

• Convert from a referencing matrix to a map reference object by using the refmatToMapRasterReference function.

Once you have created a map reference object, replace uses of the referencing matrix in your code with the map reference object.