// creating a zip outputstream
final ZipOutputStream outZ = new ZipOutputStream(output);
output = outZ;
// creating a writer
final GridCoverageWriter writer = new GTopo30Writer(outZ);
// writing
if (writer != null) {
writer.write(sourceCoverage, null);
} else {
throw new ServiceException("Could not create a writer for the format Gtopo30!");
}
// freeing everything
writer.dispose();
this.sourceCoverage.dispose(false);
this.sourceCoverage = null;
}