Problem reading BIL files

[bradley@…]

If I read a spectral component from a BIL file using GDALRasterBand::RasterIO I 
get the data values for the first spectral component regardless of which 
component I ask for. I am using GDAL version 1.1.9 on Windows 2000.

The file that is causing problems is a 602x630 pixel RGB BIL file. Here is the 
header file

BYTEORDER      I
LAYOUT       BIL
NROWS         630
NCOLS         602
NBANDS        3
NBITS         8
BANDROWBYTES         602
TOTALROWBYTES        1806
BANDGAPBYTES         0

Below is a short example program that illustrates the problem. This program 
extracts a single band from the input file and writes it to a file 
called "x.raw". The index of the spectral band is specified at line 35 and must 
be set to 1, 2, or 3.

I tried running this test program with a TIFF version of the ubiquitous Lena 
image and that works fine.


#include <string>
#include "vrtdataset.h"
#include "cpl_vsi.h"
#include "cpl_conv.h"
#include "cpl_string.h"
#include "gdal_priv.h"

#include <iostream>
#include <fstream>

int main( void ) {

	GDALAllRegister();
	const std::string filename( "sub2807.bil" );
//	const std::string filename( "lena.tif" ); // the Lena image works OK!!!
	GDALDatasetH hDataset = GDALOpen( filename.c_str(), GA_ReadOnly );

	const int width = GDALGetRasterXSize( hDataset );
	const int height = GDALGetRasterYSize( hDataset );
	const int samples_per_pixel = GDALGetRasterCount( hDataset );

	unsigned char *buffer = new unsigned char[ width * height ];
	const GDALDataType data_type = GDT_Byte;

	const GDALRWFlag eRWFlag = GF_Read;
	const int nXOff = 0;
	const int nYOff = 0;
	const int nXSize = width;
	const int nYSize = height;
	const int nBufXSize = width;
	const int nBufYSize = height;
	const int nPixelSpace = 0; // use default, i.e., sizeof(GDT_Byte)
	const int nLineSpace = width;

	const int comp_idx = 1; // SET THE COMPONENT INDEX HERE TO 1, 2 OR 3

	GDALRasterBand *band = ((GDALDataset*)hDataset)->GetRasterBand
(comp_idx);

	// extract the specified component
	CPLErr error = band->RasterIO (
		eRWFlag,
		nXOff,
		nYOff,
		nXSize,
		nYSize,
		buffer,
		nBufXSize,
		nBufYSize,
		data_type,
		nPixelSpace,
		nLineSpace );

	if( error == CE_Failure ) {
		std::cerr << "Error reading data.\n";
		return 1;
	}

	// write the component to the file "x.raw"
	std::ofstream ofs( "x.raw", std::ios::binary );
	ofs.write( (char*)buffer, width * height );
	if( ofs.fail() ) {
		std::cerr << "Error writing data.\n";
		return 1;
	}

	return 0;
}

[warmerdam]

Jonathan,

I have corrected the EHdr driver to support multi-band datasets, but due to 
a paucity of example files I can't be sure how correct it is.  The fixes are
committed to CVS.  Let me know if your problems persists.