/******************************************************************************
* $Id: btdataset.cpp,v 1.7 2005/05/05 13:55:41 fwarmerdam Exp $
*
* Project: VTP .bt Driver
* Purpose: Implementation of VTP .bt elevation format read/write support.
* http://www.vterrain.org/Implementation/Formats/BT.html
* Author: Frank Warmerdam, warmerdam@pobox.com
*
******************************************************************************
* Copyright (c) 2003, Frank Warmerdam
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
******************************************************************************
*
* $Log: btdataset.cpp,v $
* Revision 1.7 2005/05/05 13:55:41 fwarmerdam
* PAM Enable
*
* Revision 1.6 2004/05/11 17:27:33 warmerda
* Set eAccess properly in Open().
*
* Revision 1.5 2004/03/02 15:14:07 warmerda
* Fixed CPL_MSB case.
*
* Revision 1.4 2004/03/01 17:55:10 warmerda
* rewrote to *not* use raw layer
*
* Revision 1.3 2004/01/08 20:13:33 warmerda
* Fixed bugs with georeferencing (on read), and with imagery access
* (was diagonally flipped). Note, that BT imagery is column organized,
* like USGS DEMs, not row oriented as the raw driver is optimized for.
*
* Revision 1.2 2003/12/11 22:44:11 warmerda
* ensure external .prj flag gets set
*
* Revision 1.1 2003/12/11 06:18:18 warmerda
* New
*
*/
#include "rawdataset.h"
#include "ogr_spatialref.h"
CPL_CVSID("$Id: btdataset.cpp,v 1.7 2005/05/05 13:55:41 fwarmerdam Exp $");
CPL_C_START
void GDALRegister_BT(void);
CPL_C_END
/************************************************************************/
/* ==================================================================== */
/* BTRasterBand */
/* ==================================================================== */
/************************************************************************/
class BTRasterBand : public GDALRasterBand
{
FILE *fpImage;
public:
BTRasterBand( GDALDataset * poDS, FILE * fp,
GDALDataType eType );
virtual CPLErr IReadBlock( int, int, void * );
virtual CPLErr IWriteBlock( int, int, void * );
};
/************************************************************************/
/* BTRasterBand() */
/************************************************************************/
BTRasterBand::BTRasterBand( GDALDataset *poDS, FILE *fp, GDALDataType eType )
{
this->poDS = poDS;
this->nBand = 1;
this->eDataType = eType;
this->fpImage = fp;
nBlockXSize = 1;
nBlockYSize = poDS->GetRasterYSize();
}
/************************************************************************/
/* IReadBlock() */
/************************************************************************/
CPLErr BTRasterBand::IReadBlock( int nBlockXOff, int nBlockYOff,
void * pImage )
{
int nDataSize = GDALGetDataTypeSize( eDataType ) / 8;
int i;
CPLAssert( nBlockYOff == 0 );
/* -------------------------------------------------------------------- */
/* Seek to profile. */
/* -------------------------------------------------------------------- */
if( VSIFSeekL( fpImage,
256 + nBlockXOff * nDataSize * nRasterYSize,
SEEK_SET ) != 0 )
{
CPLError( CE_Failure, CPLE_FileIO,
".bt Seek failed:%s", VSIStrerror( errno ) );
return CE_Failure;
}
/* -------------------------------------------------------------------- */
/* Read the profile. */
/* -------------------------------------------------------------------- */
if( VSIFReadL( pImage, nDataSize, nRasterYSize, fpImage ) !=
(size_t) nRasterYSize )
{
CPLError( CE_Failure, CPLE_FileIO,
".bt Read failed:%s", VSIStrerror( errno ) );
return CE_Failure;
}
/* -------------------------------------------------------------------- */
/* Swap on MSB platforms. */
/* -------------------------------------------------------------------- */
#ifdef CPL_MSB
GDALSwapWords( pImage, nDataSize, nRasterYSize, nDataSize );
#endif
/* -------------------------------------------------------------------- */
/* Vertical flip, since GDAL expects values from top to bottom, */
/* but in .bt they are bottom to top. */
/* -------------------------------------------------------------------- */
for( i = 0; i < nRasterYSize / 2; i++ )
{
GByte abyWrk[8];
memcpy( abyWrk, ((GByte *) pImage) + i * nDataSize, nDataSize );
memcpy( ((GByte *) pImage) + i * nDataSize,
((GByte *) pImage) + (nRasterYSize - i - 1) * nDataSize,
nDataSize );
memcpy( ((GByte *) pImage) + (nRasterYSize - i - 1) * nDataSize,
abyWrk, nDataSize );
}
return CE_None;
}
/************************************************************************/
/* IWriteBlock() */
/************************************************************************/
CPLErr BTRasterBand::IWriteBlock( int nBlockXOff, int nBlockYOff,
void * pImage )
{
int nDataSize = GDALGetDataTypeSize( eDataType ) / 8;
GByte *pabyWrkBlock;
int i;
CPLAssert( nBlockYOff == 0 );
/* -------------------------------------------------------------------- */
/* Seek to profile. */
/* -------------------------------------------------------------------- */
if( VSIFSeekL( fpImage,
256 + nBlockXOff * nDataSize * nRasterYSize,
SEEK_SET ) != 0 )
{
CPLError( CE_Failure, CPLE_FileIO,
".bt Seek failed:%s", VSIStrerror( errno ) );
return CE_Failure;
}
/* -------------------------------------------------------------------- */
/* Allocate working buffer. */
/* -------------------------------------------------------------------- */
pabyWrkBlock = (GByte *) CPLMalloc(nDataSize * nRasterYSize);
/* -------------------------------------------------------------------- */
/* Vertical flip data into work buffer, since GDAL expects */
/* values from top to bottom, but in .bt they are bottom to */
/* top. */
/* -------------------------------------------------------------------- */
for( i = 0; i < nRasterYSize; i++ )
{
memcpy( pabyWrkBlock + (nRasterYSize - i - 1) * nDataSize,
((GByte *) pImage) + i * nDataSize, nDataSize );
}
/* -------------------------------------------------------------------- */
/* Swap on MSB platforms. */
/* -------------------------------------------------------------------- */
#ifdef CPL_MSB
GDALSwapWords( pabyWrkBlock, nDataSize, nRasterYSize, nDataSize );
#endif
/* -------------------------------------------------------------------- */
/* Read the profile. */
/* -------------------------------------------------------------------- */
if( VSIFWriteL( pabyWrkBlock, nDataSize, nRasterYSize, fpImage ) !=
(size_t) nRasterYSize )
{
CPLFree( pabyWrkBlock );
CPLError( CE_Failure, CPLE_FileIO,
".bt Write failed:%s", VSIStrerror( errno ) );
return CE_Failure;
}
CPLFree( pabyWrkBlock );
return CE_None;
}
/************************************************************************/
/* ==================================================================== */
/* BTDataset */
/* ==================================================================== */
/************************************************************************/
class BTDataset : public GDALPamDataset
{
FILE *fpImage; // image data file.
int bGeoTransformValid;
double adfGeoTransform[6];
char *pszProjection;
double dfVScale;
int nVersionCode; // version times 10.
int bHeaderModified;
unsigned char abyHeader[256];
public:
BTDataset();
~BTDataset();
virtual const char *GetProjectionRef(void);
virtual CPLErr SetProjection( const char * );
virtual CPLErr GetGeoTransform( double * );
virtual CPLErr SetGeoTransform( double * );
virtual void FlushCache();
static GDALDataset *Open( GDALOpenInfo * );
static GDALDataset *Create( const char * pszFilename,
int nXSize, int nYSize, int nBands,
GDALDataType eType, char ** papszOptions );
};
/************************************************************************/
/* BTDataset() */
/************************************************************************/
BTDataset::BTDataset()
{
fpImage = NULL;
bGeoTransformValid = FALSE;
adfGeoTransform[0] = 0.0;
adfGeoTransform[1] = 1.0;
adfGeoTransform[2] = 0.0;
adfGeoTransform[3] = 0.0;
adfGeoTransform[4] = 0.0;
adfGeoTransform[5] = 1.0;
pszProjection = NULL;
bHeaderModified = FALSE;
}
/************************************************************************/
/* ~BTDataset() */
/************************************************************************/
BTDataset::~BTDataset()
{
FlushCache();
if( fpImage != NULL )
VSIFCloseL( fpImage );
CPLFree( pszProjection );
}
/************************************************************************/
/* FlushCache() */
/* */
/* We override this to include flush out the header block. */
/************************************************************************/
void BTDataset::FlushCache()
{
GDALDataset::FlushCache();
if( !bHeaderModified )
return;
bHeaderModified = FALSE;
VSIFSeekL( fpImage, 0, SEEK_SET );
VSIFWriteL( abyHeader, 256, 1, fpImage );
}
/************************************************************************/
/* GetGeoTransform() */
/************************************************************************/
CPLErr BTDataset::GetGeoTransform( double * padfTransform )
{
memcpy( padfTransform, adfGeoTransform, sizeof(double)*6 );
if( bGeoTransformValid )
return CE_None;
else
return CE_Failure;
}
/************************************************************************/
/* SetGeoTransform() */
/************************************************************************/
CPLErr BTDataset::SetGeoTransform( double *padfTransform )
{
CPLErr eErr = CE_None;
memcpy( adfGeoTransform, padfTransform, sizeof(double) * 6 );
if( adfGeoTransform[2] != 0.0 || adfGeoTransform[4] != 0.0 )
{
CPLError( CE_Failure, CPLE_AppDefined,
".bt format does not support rotational coefficients in geotransform, ignoring." );
eErr = CE_Failure;
}
/* -------------------------------------------------------------------- */
/* Compute bounds, and update header info. */
/* -------------------------------------------------------------------- */
double dfLeft, dfRight, dfTop, dfBottom;
dfLeft = adfGeoTransform[0];
dfRight = dfLeft + adfGeoTransform[1] * nRasterXSize;
dfTop = adfGeoTransform[3];
dfBottom = dfTop + adfGeoTransform[5] * nRasterYSize;
memcpy( abyHeader + 28, &dfLeft, 8 );
memcpy( abyHeader + 36, &dfRight, 8 );
memcpy( abyHeader + 44, &dfBottom, 8 );
memcpy( abyHeader + 52, &dfTop, 8 );
CPL_LSBPTR64( abyHeader + 28 );
CPL_LSBPTR64( abyHeader + 36 );
CPL_LSBPTR64( abyHeader + 44 );
CPL_LSBPTR64( abyHeader + 52 );
bHeaderModified = TRUE;
return eErr;
}
/************************************************************************/
/* GetProjectionRef() */
/************************************************************************/
const char *BTDataset::GetProjectionRef()
{
if( pszProjection == NULL )
return "";
else
return pszProjection;
}
/************************************************************************/
/* SetProjection() */
/************************************************************************/
CPLErr BTDataset::SetProjection( const char *pszNewProjection )
{
CPLErr eErr = CE_None;
CPLFree( pszProjection );
pszProjection = CPLStrdup( pszNewProjection );
bHeaderModified = TRUE;
/* -------------------------------------------------------------------- */
/* Parse projection. */
/* -------------------------------------------------------------------- */
OGRSpatialReference oSRS( pszProjection );
GInt16 nShortTemp;
/* -------------------------------------------------------------------- */
/* Linear units. */
/* -------------------------------------------------------------------- */
if( oSRS.IsGeographic() )
nShortTemp = 0;
else
{
double dfLinear = oSRS.GetLinearUnits();
if( ABS(dfLinear - 0.3048) < 0.0000001 )
nShortTemp = 2;
else if( ABS(dfLinear - atof(SRS_UL_US_FOOT_CONV)) < 0.00000001 )
nShortTemp = 3;
else
nShortTemp = 1;
}
nShortTemp = CPL_LSBWORD16( 1 );
memcpy( abyHeader + 22, &nShortTemp, 2 );
/* -------------------------------------------------------------------- */
/* UTM Zone */
/* -------------------------------------------------------------------- */
int bNorth;
nShortTemp = oSRS.GetUTMZone( &bNorth );
if( bNorth )
nShortTemp = -nShortTemp;
nShortTemp = CPL_LSBWORD16( nShortTemp );
memcpy( abyHeader + 24, &nShortTemp, 2 );
/* -------------------------------------------------------------------- */
/* Datum */
/* -------------------------------------------------------------------- */
if( oSRS.GetAuthorityName( "GEOGCS|DATUM" ) != NULL
&& EQUAL(oSRS.GetAuthorityName( "GEOGCS|DATUM" ),"EPSG") )
nShortTemp = atoi(oSRS.GetAuthorityName( "GEOGCS|DATUM" )) + 2000;
else
nShortTemp = -2;
nShortTemp = CPL_LSBWORD16( nShortTemp ); /* datum unknown */
memcpy( abyHeader + 26, &nShortTemp, 2 );
/* -------------------------------------------------------------------- */
/* Write out the projection to a .prj file. */
/* -------------------------------------------------------------------- */
const char *pszPrjFile = CPLResetExtension( GetDescription(), "prj" );
FILE * fp;
fp = VSIFOpen( pszPrjFile, "wt" );
if( fp != NULL )
{
VSIFPrintf( fp, "%s\n", pszProjection );
VSIFClose( fp );
abyHeader[60] = 1;
}
else
{
CPLError( CE_Failure, CPLE_AppDefined,
"Unable to write out .prj file." );
eErr = CE_Failure;
}
return eErr;
}
/************************************************************************/
/* Open() */
/************************************************************************/
GDALDataset *BTDataset::Open( GDALOpenInfo * poOpenInfo )
{
/* -------------------------------------------------------------------- */
/* Verify that this is some form of binterr file. */
/* -------------------------------------------------------------------- */
if( poOpenInfo->nHeaderBytes < 256 || poOpenInfo->fp == NULL )
return NULL;
if( strncmp( (const char *) poOpenInfo->pabyHeader, "binterr", 7 ) != 0 )
return NULL;
/* -------------------------------------------------------------------- */
/* Create the dataset. */
/* -------------------------------------------------------------------- */
BTDataset *poDS;
poDS = new BTDataset();
memcpy( poDS->abyHeader, poOpenInfo->pabyHeader, 256 );
/* -------------------------------------------------------------------- */
/* Get the version. */
/* -------------------------------------------------------------------- */
char szVersion[4];
strncpy( szVersion, (char *) (poDS->abyHeader + 7), 3 );
szVersion[3] = '\0';
poDS->nVersionCode = (int) (atof(szVersion) * 10);
/* -------------------------------------------------------------------- */
/* Extract core header information, being careful about the */
/* version. */
/* -------------------------------------------------------------------- */
GInt32 nIntTemp;
GInt16 nDataSize;
GDALDataType eType;
memcpy( &nIntTemp, poDS->abyHeader + 10, 4 );
poDS->nRasterXSize = CPL_LSBWORD32( nIntTemp );
memcpy( &nIntTemp, poDS->abyHeader + 14, 4 );
poDS->nRasterYSize = CPL_LSBWORD32( nIntTemp );
memcpy( &nDataSize, poDS->abyHeader+18, 2 );
nDataSize = CPL_LSBWORD16( nDataSize );
if( poDS->abyHeader[20] != 0 && nDataSize == 4 )
eType = GDT_Float32;
else if( poDS->abyHeader[20] == 0 && nDataSize == 4 )
eType = GDT_Int32;
else if( poDS->abyHeader[20] == 0 && nDataSize == 2 )
eType = GDT_Int16;
else
{
CPLError( CE_Failure, CPLE_AppDefined,
".bt file data type unknown, got datasize=%d.",
nDataSize );
return NULL;
}
/* -------------------------------------------------------------------- */
/* Try to read a .prj file if it is indicated. */
/* -------------------------------------------------------------------- */
OGRSpatialReference oSRS;
if( poDS->nVersionCode >= 12 && poDS->abyHeader[60] != 0 )
{
const char *pszPrjFile = CPLResetExtension( poOpenInfo->pszFilename,
"prj" );
FILE *fp;
fp = VSIFOpen( pszPrjFile, "rt" );
if( fp != NULL )
{
char *pszBuffer, *pszBufPtr;
int nBufMax = 100000;
int nBytes;
pszBuffer = (char *) CPLMalloc(nBufMax);
nBytes = VSIFRead( pszBuffer, 1, nBufMax-1, fp );
VSIFClose( fp );
pszBuffer[nBytes] = '\0';
pszBufPtr = pszBuffer;
if( oSRS.importFromWkt( &pszBufPtr ) != OGRERR_NONE )
{
CPLError( CE_Warning, CPLE_AppDefined,
"Unable to parse .prj file, coordinate system missing." );
}
CPLFree( pszBuffer );
}
}
/* -------------------------------------------------------------------- */
/* If we didn't find a .prj file, try to use internal info. */
/* -------------------------------------------------------------------- */
if( oSRS.GetRoot() == NULL )
{
GInt16 nUTMZone, nDatum, nHUnits;
memcpy( &nUTMZone, poDS->abyHeader + 24, 2 );
nUTMZone = CPL_LSBWORD16( nUTMZone );
memcpy( &nDatum, poDS->abyHeader + 26, 2 );
nDatum = CPL_LSBWORD16( nDatum );
memcpy( &nHUnits, poDS->abyHeader + 22, 2 );
nHUnits = CPL_LSBWORD16( nHUnits );
if( nUTMZone != 0 )
oSRS.SetUTM( ABS(nUTMZone), nUTMZone > 0 );
else if( nHUnits != 0 )
oSRS.SetLocalCS( "Unknown" );
if( nHUnits == 1 )
oSRS.SetLinearUnits( SRS_UL_METER, 1.0 );
else if( nHUnits == 2 )
oSRS.SetLinearUnits( SRS_UL_FOOT, atof(SRS_UL_FOOT_CONV) );
else if( nHUnits == 3 )
oSRS.SetLinearUnits( SRS_UL_US_FOOT, atof(SRS_UL_US_FOOT_CONV) );
// Translate some of the more obvious old USGS datum codes
if( nDatum == 0 )
nDatum = 6201;
else if( nDatum == 1 )
nDatum = 6209;
else if( nDatum == 2 )
nDatum = 6210;
else if( nDatum == 3 )
nDatum = 6202;
else if( nDatum == 4 )
nDatum = 6203;
else if( nDatum == 4 )
nDatum = 6203;
else if( nDatum == 6 )
nDatum = 6222;
else if( nDatum == 7 )
nDatum = 6230;
else if( nDatum == 13 )
nDatum = 6267;
else if( nDatum == 14 )
nDatum = 6269;
else if( nDatum == 17 )
nDatum = 6277;
else if( nDatum == 19 )
nDatum = 6284;
else if( nDatum == 21 )
nDatum = 6301;
else if( nDatum == 22 )
nDatum = 6322;
else if( nDatum == 23 )
nDatum = 6326;
if( !oSRS.IsLocal() )
{
if( nDatum >= 6000 )
{
char szName[32];
sprintf( szName, "EPSG:%d", nDatum-2000 );
oSRS.SetWellKnownGeogCS( szName );
}
else
oSRS.SetWellKnownGeogCS( "WGS84" );
}
}
/* -------------------------------------------------------------------- */
/* Convert coordinate system back to WKT. */
/* -------------------------------------------------------------------- */
if( oSRS.GetRoot() != NULL )
oSRS.exportToWkt( &poDS->pszProjection );
/* -------------------------------------------------------------------- */
/* Get georeferencing bounds. */
/* -------------------------------------------------------------------- */
if( poDS->nVersionCode >= 11 )
{
double dfLeft, dfRight, dfTop, dfBottom;
memcpy( &dfLeft, poDS->abyHeader + 28, 8 );
CPL_LSBPTR64( &dfLeft );
memcpy( &dfRight, poDS->abyHeader + 36, 8 );
CPL_LSBPTR64( &dfRight );
memcpy( &dfBottom, poDS->abyHeader + 44, 8 );
CPL_LSBPTR64( &dfBottom );
memcpy( &dfTop, poDS->abyHeader + 52, 8 );
CPL_LSBPTR64( &dfTop );
poDS->adfGeoTransform[0] = dfLeft;
poDS->adfGeoTransform[1] = (dfRight - dfLeft) / poDS->nRasterXSize;
poDS->adfGeoTransform[2] = 0.0;
poDS->adfGeoTransform[3] = dfTop;
poDS->adfGeoTransform[4] = 0.0;
poDS->adfGeoTransform[5] = (dfBottom - dfTop) / poDS->nRasterYSize;
poDS->bGeoTransformValid = TRUE;
}
/* -------------------------------------------------------------------- */
/* Re-open the file with the desired access. */
/* -------------------------------------------------------------------- */
VSIFClose( poOpenInfo->fp );
poOpenInfo->fp = NULL;
if( poOpenInfo->eAccess == GA_Update )
poDS->fpImage = VSIFOpenL( poOpenInfo->pszFilename, "rb+" );
else
poDS->fpImage = VSIFOpenL( poOpenInfo->pszFilename, "rb" );
if( poDS->fpImage == NULL )
{
CPLError( CE_Failure, CPLE_OpenFailed,
"Failed to re-open %s within BT driver.\n",
poOpenInfo->pszFilename );
return NULL;
}
poDS->eAccess = poOpenInfo->eAccess;
/* -------------------------------------------------------------------- */
/* Create band information objects */
/* -------------------------------------------------------------------- */
poDS->SetBand( 1, new BTRasterBand( poDS, poDS->fpImage, eType ) );
/* -------------------------------------------------------------------- */
/* Check for overviews. */
/* -------------------------------------------------------------------- */
poDS->oOvManager.Initialize( poDS, poOpenInfo->pszFilename );
#ifdef notdef
poDS->bGeoTransformValid =
GDALReadWorldFile( poOpenInfo->pszFilename, ".wld",
poDS->adfGeoTransform );
#endif
/* -------------------------------------------------------------------- */
/* Initialize any PAM information. */
/* -------------------------------------------------------------------- */
poDS->SetDescription( poOpenInfo->pszFilename );
poDS->TryLoadXML();
return( poDS );
}
/************************************************************************/
/* Create() */
/************************************************************************/
GDALDataset *BTDataset::Create( const char * pszFilename,
int nXSize, int nYSize, int nBands,
GDALDataType eType,
char ** papszOptions )
{
/* -------------------------------------------------------------------- */
/* Verify input options. */
/* -------------------------------------------------------------------- */
if( eType != GDT_Int16 && eType != GDT_Int32 && eType != GDT_Float32 )
{
CPLError( CE_Failure, CPLE_AppDefined,
"Attempt to create .bt dataset with an illegal\n"
"data type (%s), only Int16, Int32 and Float32 supported.\n",
GDALGetDataTypeName(eType) );
return NULL;
}
if( nBands != 1 )
{
CPLError( CE_Failure, CPLE_AppDefined,
"Attempt to create .bt dataset with %d bands, only 1 supported",
nBands );
return NULL;
}
/* -------------------------------------------------------------------- */
/* Try to create the file. */
/* -------------------------------------------------------------------- */
FILE *fp;
fp = VSIFOpenL( pszFilename, "wb" );
if( fp == NULL )
{
CPLError( CE_Failure, CPLE_OpenFailed,
"Attempt to create file `%s' failed.\n",
pszFilename );
return NULL;
}
/* -------------------------------------------------------------------- */
/* Setup base header. */
/* -------------------------------------------------------------------- */
unsigned char abyHeader[256];
GInt32 nTemp;
GInt16 nShortTemp;
memset( abyHeader, 0, 256 );
memcpy( abyHeader, "binterr1.3", 10 );
nTemp = CPL_LSBWORD32( nXSize );
memcpy( abyHeader+10, &nTemp, 4 );
nTemp = CPL_LSBWORD32( nYSize );
memcpy( abyHeader+14, &nTemp, 4 );
nShortTemp = CPL_LSBWORD16( GDALGetDataTypeSize( eType ) / 8 );
memcpy( abyHeader + 18, &nShortTemp, 2 );
if( eType == GDT_Float32 )
abyHeader[20] = 1;
else
abyHeader[20] = 0;
nShortTemp = CPL_LSBWORD16( 1 ); /* meters */
memcpy( abyHeader + 22, &nShortTemp, 2 );
nShortTemp = CPL_LSBWORD16( 0 ); /* not utm */
memcpy( abyHeader + 24, &nShortTemp, 2 );
nShortTemp = CPL_LSBWORD16( -2 ); /* datum unknown */
memcpy( abyHeader + 26, &nShortTemp, 2 );
/* -------------------------------------------------------------------- */
/* Set dummy extents. */
/* -------------------------------------------------------------------- */
double dfLeft=0, dfRight=nXSize, dfTop=nYSize, dfBottom=0;
memcpy( abyHeader + 28, &dfLeft, 8 );
memcpy( abyHeader + 36, &dfRight, 8 );
memcpy( abyHeader + 44, &dfBottom, 8 );
memcpy( abyHeader + 52, &dfTop, 8 );
CPL_LSBPTR64( abyHeader + 28 );
CPL_LSBPTR64( abyHeader + 36 );
CPL_LSBPTR64( abyHeader + 44 );
CPL_LSBPTR64( abyHeader + 52 );
/* -------------------------------------------------------------------- */
/* Set dummy scale. */
/* -------------------------------------------------------------------- */
float fScale = 1.0;
memcpy( abyHeader + 62, &fScale, 4 );
CPL_LSBPTR32( abyHeader + 62 );
/* -------------------------------------------------------------------- */
/* Write to disk. */
/* -------------------------------------------------------------------- */
VSIFWriteL( (void *) abyHeader, 256, 1, fp );
if( VSIFSeekL( fp, (GDALGetDataTypeSize(eType)/8) * nXSize * nYSize - 1,
SEEK_CUR ) != 0
|| VSIFWriteL( abyHeader+255, 1, 1, fp ) != 1 )
{
CPLError( CE_Failure, CPLE_FileIO,
"Failed to extent file to its full size, out of disk space?"
);
VSIFCloseL( fp );
VSIUnlink( pszFilename );
return NULL;
}
VSIFCloseL( fp );
return (GDALDataset *) GDALOpen( pszFilename, GA_Update );
}
/************************************************************************/
/* GDALRegister_BT() */
/************************************************************************/
void GDALRegister_BT()
{
GDALDriver *poDriver;
if( GDALGetDriverByName( "BT" ) == NULL )
{
poDriver = new GDALDriver();
poDriver->SetDescription( "BT" );
poDriver->SetMetadataItem( GDAL_DMD_LONGNAME,
"VTP .bt (Binary Terrain) 1.3 Format" );
poDriver->SetMetadataItem( GDAL_DMD_HELPTOPIC,
"frmt_various.html#BT" );
poDriver->SetMetadataItem( GDAL_DMD_EXTENSION, "bt" );
poDriver->SetMetadataItem( GDAL_DMD_CREATIONDATATYPES,
"Int16 Int32 Float32" );
poDriver->pfnOpen = BTDataset::Open;
poDriver->pfnCreate = BTDataset::Create;
GetGDALDriverManager()->RegisterDriver( poDriver );
}
}
