RPCCoefficientTag

Rational Polynomial Coefficients Tag

Description

RPCCoefficientTag contains the Rational Polynomial Coefficients (RPC) TIFF tag, which describes the relationship of latitude, longitude, and height locations with row and column locations in an image.

The RPCCoefficientTag object contains properties with names and permissible values corresponding to the tag elements listed in the technical note RPCs in GeoTIFF technical note, viewable at http://geotiff.maptools.org/rpc_prop.html.

Creation

• Read an RPCCoefficientTag object from a GeoTIFF file by using the georasterinfo or geotiffinfo function.

• Create an RPCCoefficientTag object by using the map.geotiff.RPCCoefficientTag function (described here).

Syntax

rpctag = map.geotiff.RPCCoefficientTag

rpctag = map.geotiff.RPCCoefficientTag(tiffTagValue)

Description

rpctag = map.geotiff.RPCCoefficientTag creates a default RPCCoefficientTag object.

rpctag = map.geotiff.RPCCoefficientTag(tiffTagValue) creates an RPCCoefficientTag object and sets the property values to the corresponding values in the 92-element vector specified in tiffTagValue.

Input Arguments

tiffTagValue — Value of RPCCoefficientTag properties

92-element vector

Value of RPCCoefficientTag properties, specified as a 92-element vector.

Data Types: double

Properties

BiasErrorInMeters — Root mean square bias error in meters per horizontal axis

-1 (default) | nonnegative scalar

Root mean square bias error in meters per horizontal axis, specified as the number -1 or a nonnegative scalar. The value is -1 only if BiasErrorInMeters is not specified

Data Types: double

RandomErrorInMeters — Root mean square random error in meters per horizontal axis

-1 (default) | nonnegative scalar

Root mean square random error in meters, specified as the number -1 or a nonnegative scalar. The value is -1 only if RandomErrorInMeters is not specified.

Data Types: double

LineOffset — Line offset in pixels

0 (default) | nonnegative scalar

Line offset in pixels, specified as a nonnegative scalar, with a value of 0 by default.

Data Types: double

SampleOffset — Sample offset in pixels

0 (default) | nonnegative scalar

Sample offset in pixels, specified as a nonnegative scalar, with a value of 0 by default.

Data Types: double

GeodeticLatitudeOffset — Geodetic latitude offset in degrees

0 (default) | numeric scalar

Geodetic latitude offset in degrees, specified as a numeric scalar. The value can range from -90 <= value <= 90.

Data Types: double

GeodeticLongitudeOffset — Geodetic longitude offset in degrees

0 (default) | numeric scalar

Geodetic longitude offset in degrees, specified as a numeric scalar. The value can range from -180 <= value <= 180.

Data Types: double

GeodeticHeightOffset — Geodetic height offset in meters

0 (default) | numeric scalar

Geodetic height offset in meters, specified as a numeric scalar.

Data Types: double

LineScale — Line scale factor in pixels

1 (default) | positive scalar

Line scale factor in pixels, specified as a positive scalar.

Data Types: double

SampleScale — Sample scale factor in pixels

1 (default) | positive scalar

Sample scale factor in pixels, specified as a positive scalar.

Data Types: double

GeodeticLatitudeScale — Geodetic latitude scale in degrees

1 (default) | positive scalar

Geodetic latitude scale in degrees, specified as a positive scalar in the range (0,90].

Data Types: double

GeodeticLongitudeScale — Geodetic longitude scale in degrees

1 (default) | positive scalar

Geodetic longitude scale in degrees, specified as positive scalar in the range (0, 180].

Data Types: double

GeodeticHeightScale — Geodetic height scale factor in meters

1 (default) | positive scalar

Geodetic height scale factor in meters, specified as a positive scalar.

Data Types: double

LineNumeratorCoefficients — Coefficients for the polynomial in the numerator of the r(n) equation

20-element row vector of zeros (default) | 20-element row vector

Coefficients for the polynomial in the numerator of the r(n) equation, specified as a 20-element row vector of class double.

Data Types: double

LineDenominatorCoefficients — Coefficients for the polynomial in the denominator of the r(n) equation

20-element row vector of zeros (default) | 20-element row vector

Coefficients for the polynomial in the denominator of the r(n) equation, specified as a 20-element row vector of class double.

Data Types: double

SampleNumeratorCoefficients — Coefficients for the polynomial in the numerator of the c(n) equation

20-element row vector of zeros (default) | 20-element row vector

Coefficients for the polynomial in the numerator of the c(n) equation, specified as a 20-element row vector of class double.

Data Types: double

SampleDenominatorCoefficients — Coefficients for the polynomial in the denominator of the c(n) equation

20-element row vector of zeros (default) | 20-element row vector

Coefficients for the polynomial in the denominator of the c(n) equation, specified as a 20-element row vector of class double.

Data Types: double

Object Functions

double

Convert TIFF tag property values to row vector of doubles

Examples

Create RPCCoefficientTag Object with Default Properties

Call the RPCCoefficientTag class constructor with no arguments.

rpctag = map.geotiff.RPCCoefficientTag

rpctag = 
  RPCCoefficientTag with properties:

                BiasErrorInMeters: -1
              RandomErrorInMeters: -1
                       LineOffset: 0
                     SampleOffset: 0
           GeodeticLatitudeOffset: 0
          GeodeticLongitudeOffset: 0
             GeodeticHeightOffset: 0
                        LineScale: 1
                      SampleScale: 1
            GeodeticLatitudeScale: 1
           GeodeticLongitudeScale: 1
              GeodeticHeightScale: 1
        LineNumeratorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
      LineDenominatorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
      SampleNumeratorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
    SampleDenominatorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]

Write Raw RPC Coefficient Metadata to GeoTIFF File

This example shows how to write RPC coefficient metadata to a TIFF file. In a real workflow, you would create the RPC coefficient metadata according to the TIFF extension specification. This example does not show the specifics of how to create valid RPC metadata. To simulate raw RPC metadata, the example creates a sample TIFF file with RPC metadata and then uses imfinfo to read this RPC metadata in raw, unprocessed form from the file. The example then writes this raw RPC metadata to a file using the geotiffwrite function.

Create Raw RPC Coefficient Metadata

To simulate raw RPC metadata, create a simple test file and write some RPC metadata to the file. For this test file, create a toy image and a referencing object associated with the image.

myimage = zeros(180,360);
latlim = [-90 90];
lonlim = [-180 180];
R = georefcells(latlim,lonlim,size(myimage));

Create an RPCCoefficientTag metadata object and set some of the fields. The toolbox uses the RPCCoefficientTag object to represent RPC metadata in human readable form.

rpctag = map.geotiff.RPCCoefficientTag;
rpctag.LineOffset = 1;
rpctag.SampleOffset = 1;
rpctag.LineScale = 2;
rpctag.SampleScale = 2;
rpctag.GeodeticHeightScale = 500;

Write the image, the associated referencing object, and the RPCCoefficientTag object to a file.

geotiffwrite('myfile',myimage,R,'RPCCoefficientTag',rpctag)

Read Raw RPC Coefficient Metadata

Read the RPC coefficient metadata from the test file using the imfinfo function. When it encounters unfamiliar metadata, imfinfo returns the data, unprocessed, in the UnknownTags field. Note that the UnknownTags field contains an array of 92 doubles. This is the raw RPC coefficient metadata, read from the file in unprocessed form.

info = imfinfo('myfile.tif');
info.UnknownTags

ans = struct with fields:
        ID: 50844
    Offset: 10680
     Value: [-1 -1 1 1 0 0 0 2 2 1 1 500 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]

Write Raw RPC Metadata to a File

Write the raw RPC metadata to a file. First, extract the RPC coefficient metadata from the info structure.

value = info.UnknownTags.Value;

Then, construct an RPCCoefficientTag object, passing the raw RPC metadata (array of 92 doubles) as an argument.

rpcdata = map.geotiff.RPCCoefficientTag(value) 

rpcdata = 
  RPCCoefficientTag with properties:

                BiasErrorInMeters: -1
              RandomErrorInMeters: -1
                       LineOffset: 1
                     SampleOffset: 1
           GeodeticLatitudeOffset: 0
          GeodeticLongitudeOffset: 0
             GeodeticHeightOffset: 0
                        LineScale: 2
                      SampleScale: 2
            GeodeticLatitudeScale: 1
           GeodeticLongitudeScale: 1
              GeodeticHeightScale: 500
        LineNumeratorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
      LineDenominatorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
      SampleNumeratorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
    SampleDenominatorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]

Pass the RPCCoefficientTag object to the geotiffwrite function and write the RPC metadata to a file.

geotiffwrite('myfile2',myimage,R,'RPCCoefficientTag',rpcdata)

To verify that the data was written to the file, read the RPC metadata from the TIFF file using geotiffinfo. Compare the returned RPC metadata with the metadata written to the test file.

ginfo = geotiffinfo('myfile2');
ginfo.GeoTIFFTags.RPCCoefficientTag

ans = 
  RPCCoefficientTag with properties:

                BiasErrorInMeters: -1
              RandomErrorInMeters: -1
                       LineOffset: 1
                     SampleOffset: 1
           GeodeticLatitudeOffset: 0
          GeodeticLongitudeOffset: 0
             GeodeticHeightOffset: 0
                        LineScale: 2
                      SampleScale: 2
            GeodeticLatitudeScale: 1
           GeodeticLongitudeScale: 1
              GeodeticHeightScale: 500
        LineNumeratorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
      LineDenominatorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
      SampleNumeratorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
    SampleDenominatorCoefficients: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]

Version History

Introduced in R2015b