Write Your Own Geospatial Utilities - Open Source Geospatial Tools: Applications in Earth Observation - page 242

#include <string>
#include <sstream>
#include <iostream>
#include <fstream>
#include "gdal_priv.h"

using namespace std;

int main( int argc, char **argv) {

string stlsSrcImageFilename;//source raster dataset filename
string stlsCtFilename;//ASCII color table filename

try {
//define error stream in case wrong arguments
ostringstream stlosError;
stlosError <<"usage: "<< argv[0] <<" -ct <asciiFilename>
→ <inputFilename>";

//loop over all command line arguments
for ( int i=1;i<argc;i++){
string stlsOption=argv[i];//convert to std::string
if (stlsOption=="-h"||stlsOption=="--help")
throw (stlosError.str());
else if (stlsOption=="-ct"||stlsOption=="--color table"){
stlsCtFilename=argv[++i];
}
else if (stlsOption.find('-')==0){
cerr <<"Error: unknown option "<< stlsOption << endl;
throw (stlosError.str());
}
else if (stlsSrcImageFilename.empty()){
stlsSrcImageFilename=argv[i];
}
else {
cerr <<"Error: multiple raster files are not supported"<<
→ endl;
throw (stlosError.str());
}

}
if (stlsSrcImageFilename.empty()){
cerr <<"Error: no raster file provided"<< endl;
throw (stlosError.str());

}

}
catch (string stlsError){
cout << stlsError << endl;
exit(1);

}

//create color table here...
return 0;

}

The class provided by GDAL for color tables is GDALColorTable . Each line
in the color table corresponds to an id and an entry . The entry is a structure that
contains the color components. The interpretation of these components depends on
how the constructor of the class GDALColorTable was defined. 21 By default the

21 GPI_RGB (red, green, blue and alpha), GPI_Gray (single gray scale component only),
GPI_CMYK (cyan, magenta, yellow and black) and GPI_HLS (hue, lightness and saturation).