worldfileread

Read world file and return reference object

Syntaxes of the worldfileread function that return referencing matrices have been removed. Use a syntax that returns a reference object instead. For more information, see Version History.

Syntax

R = worldfileread(worldFileName,coordinateSystemType,rasterSize)

Description

R = worldfileread(worldFileName,coordinateSystemType,rasterSize) creates a raster reference object R from the world file worldFileName. The argument coordinateSystemType specifies the type of reference object. The rasterSize argument specifies the size of the image that is associated with the world file.

Examples

Read Image Referenced to Projected Coordinate System

Read an orthophoto referenced to a projected coordinate system into the workspace.

filename = "concord_ortho_w.tif";
[X,cmap] = imread(filename);

Get the name of the world file from the name of the image file.

worldFileName = getworldfilename(filename);

Create a reference object for the orthophoto by reading the world file.

R = worldfileread(worldFileName,"planar",size(X))

R = 
  MapCellsReference with properties:

            XWorldLimits: [207000 209000]
            YWorldLimits: [911000 913000]
              RasterSize: [2000 2000]
    RasterInterpretation: 'cells'
        ColumnsStartFrom: 'north'
           RowsStartFrom: 'west'
      CellExtentInWorldX: 1
      CellExtentInWorldY: 1
    RasterExtentInWorldX: 2000
    RasterExtentInWorldY: 2000
        XIntrinsicLimits: [0.5 2000.5]
        YIntrinsicLimits: [0.5 2000.5]
      TransformationType: 'rectilinear'
    CoordinateSystemType: 'planar'
            ProjectedCRS: []

Read Image Referenced to Geographic Coordinate System

Read an image referenced to a geographic coordinate system into the workspace.

filename = "boston_ovr.jpg";
RGB = imread(filename);

Get the name of the world file from the name of the image file.

worldFileName = getworldfilename(filename);

Create a reference object for the orthophoto by reading the world file.

R = worldfileread(worldFileName,"geographic",size(RGB))

R = 
  GeographicCellsReference with properties:

             LatitudeLimits: [42.3052018188767 42.4165064733949]
            LongitudeLimits: [-71.1308390797572 -70.9898400731705]
                 RasterSize: [769 722]
       RasterInterpretation: 'cells'
           ColumnsStartFrom: 'north'
              RowsStartFrom: 'west'
       CellExtentInLatitude: 0.000144739472715501
      CellExtentInLongitude: 0.000195289482807142
     RasterExtentInLatitude: 0.11130465451822
    RasterExtentInLongitude: 0.140999006586757
           XIntrinsicLimits: [0.5 722.5]
           YIntrinsicLimits: [0.5 769.5]
       CoordinateSystemType: 'geographic'
              GeographicCRS: []
                  AngleUnit: 'degree'

Input Arguments

worldFileName — Name of world file

string scalar | character vector

Name of the world file, specified as a string scalar or a character vector.

Data Types: char | string

coordinateSystemType — Type of coordinate system

"planar" | "geographic"

Type of coordinate system, specified as one of the following:

• "geographic" — Geographic coordinate system. This option creates a GeographicCellsReference object.

• "planar" — Planar map coordinate system. This option creates a MapCellsReference object.

rasterSize — Size of the image associated with world file

two-element vector

Size of the image that is associated with the world file, specified as a two-element vector, [m n], where m is the number of rows in the image and n is the number of columns in the image.

Data Types: double

Output Arguments

R — Raster reference object

raster reference object

Raster reference object, returned as a GeographicCellsReference or MapCellsReference object. The raster reference associates each element of the image with a location in geographic or planar coordinates.

Version History

Introduced before R2006a

R2023b: Syntaxes that return referencing matrices have been removed

Syntaxes of the worldfileread function that return referencing matrices have been removed. Use syntaxes that return reference objects 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. For more information about reference object properties, see the GeographicCellsReference and MapPostingsReference objects.

• 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.

• Most functions that accept referencing matrices as inputs also accept reference objects.

To update your code, specify the coordinate system type as a second argument. Use "planar" for planar map coordinates or "geographic" for geographic coordinates. Specify the size of the associated raster, A, as a third argument.

Removed	Recommended
refmat = worldfileread(worldFileName);	R = worldfileread(worldFileName, ... coordinateSystemType,size(A));

R2022a: Syntaxes that return referencing matrices warn

Syntaxes of the worldfileread function that return referencing matrices issue a warning that they will be removed in a future release.

R2020b: Syntaxes that return referencing matrices will be removed

Syntaxes of the worldfileread function that return referencing matrices will be removed in a future release.