GDALDataset *SDTSDataset::Open( GDALOpenInfo * poOpenInfo )
{
int i;
/* -------------------------------------------------------------------- */
/* Before trying SDTSOpen() we first verify that the first */
/* record is in fact a SDTS file descriptor record. */
/* -------------------------------------------------------------------- */
char *pachLeader = (char *) poOpenInfo->pabyHeader;
if( poOpenInfo->nHeaderBytes < 24 )
return NULL;
if( pachLeader[5] != '1' && pachLeader[5] != '2' && pachLeader[5] != '3' )
return NULL;
if( pachLeader[6] != 'L' )
return NULL;
if( pachLeader[8] != '1' && pachLeader[8] != ' ' )
return NULL;
/* -------------------------------------------------------------------- */
/* Try opening the dataset. */
/* -------------------------------------------------------------------- */
SDTSTransfer *poTransfer = new SDTSTransfer;
if( !poTransfer->Open( poOpenInfo->pszFilename ) )
{
delete poTransfer;
return NULL;
}
/* -------------------------------------------------------------------- */
/* Confirm the requested access is supported. */
/* -------------------------------------------------------------------- */
if( poOpenInfo->eAccess == GA_Update )
{
delete poTransfer;
CPLError( CE_Failure, CPLE_NotSupported,
"The SDTS driver does not support update access to existing"
" datasets.\n" );
return NULL;
}
/* -------------------------------------------------------------------- */
/* Find the first raster layer. If there are none, abort */
/* returning an error. */
/* -------------------------------------------------------------------- */
SDTSRasterReader *poRL = NULL;
for( i = 0; i < poTransfer->GetLayerCount(); i++ )
{
if( poTransfer->GetLayerType( i ) == SLTRaster )
{
poRL = poTransfer->GetLayerRasterReader( i );
break;
}
}
if( poRL == NULL )
{
delete poTransfer;
CPLError( CE_Warning, CPLE_AppDefined,
"%s is an SDTS transfer, but has no raster cell layers.\n"
"Perhaps it is a vector transfer?\n",
poOpenInfo->pszFilename );
return NULL;
}
/* -------------------------------------------------------------------- */
/* Initialize a corresponding GDALDataset. */
/* -------------------------------------------------------------------- */
SDTSDataset *poDS = new SDTSDataset();
poDS->poTransfer = poTransfer;
poDS->poRL = poRL;
/* -------------------------------------------------------------------- */
/* Capture some information from the file that is of interest. */
/* -------------------------------------------------------------------- */
poDS->nRasterXSize = poRL->GetXSize();
poDS->nRasterYSize = poRL->GetYSize();
/* -------------------------------------------------------------------- */
/* Create band information objects. */
/* -------------------------------------------------------------------- */
poDS->nBands = 1;
poDS->papoBands = (GDALRasterBand **)
VSICalloc(sizeof(GDALRasterBand *),poDS->nBands);
for( i = 0; i < poDS->nBands; i++ )
poDS->SetBand( i+1, new SDTSRasterBand( poDS, i+1, poRL ) );
/* -------------------------------------------------------------------- */
/* Try to establish the projection string. For now we only */
/* support UTM and GEO. */
/* -------------------------------------------------------------------- */
OGRSpatialReference oSRS;
SDTS_XREF *poXREF = poTransfer->GetXREF();
if( EQUAL(poXREF->pszSystemName,"UTM") )
{
oSRS.SetUTM( poXREF->nZone );
}
else if( EQUAL(poXREF->pszSystemName,"GEO") )
{
/* we set datum later */
}
else
oSRS.SetLocalCS( poXREF->pszSystemName );
if( oSRS.IsLocal() )
/* don't try to set datum. */;
else if( EQUAL(poXREF->pszDatum,"NAS") )
oSRS.SetWellKnownGeogCS( "NAD27" );
else if( EQUAL(poXREF->pszDatum, "NAX") )
oSRS.SetWellKnownGeogCS( "NAD83" );
else if( EQUAL(poXREF->pszDatum, "WGC") )
oSRS.SetWellKnownGeogCS( "WGS72" );
else if( EQUAL(poXREF->pszDatum, "WGE") )
oSRS.SetWellKnownGeogCS( "WGS84" );
else
oSRS.SetWellKnownGeogCS( "WGS84" );
oSRS.Fixup();
poDS->pszProjection = NULL;
if( oSRS.exportToWkt( &poDS->pszProjection ) != OGRERR_NONE )
poDS->pszProjection = CPLStrdup("");
/* -------------------------------------------------------------------- */
/* Get metadata from the IDEN file. */
/* -------------------------------------------------------------------- */
const char* pszIDENFilePath = poTransfer->GetCATD()->GetModuleFilePath("IDEN");
if (pszIDENFilePath)
{
DDFModule oIDENFile;
if( oIDENFile.Open( pszIDENFilePath ) )
{
DDFRecord* poRecord;
while( (poRecord = oIDENFile.ReadRecord()) != NULL )
{
if( poRecord->GetStringSubfield( "IDEN", 0, "MODN", 0 ) == NULL )
continue;
static const char* fields[][2] = { { "TITL", "TITLE" },
{ "DAID", "DATASET_ID" },
{ "DAST", "DATA_STRUCTURE" },
{ "MPDT", "MAP_DATE" },
{ "DCDT", "DATASET_CREATION_DATE" } };
for (i = 0; i < (int)sizeof(fields) / (int)sizeof(fields[0]) ; i++)
{
const char* pszFieldValue =
poRecord->GetStringSubfield( "IDEN", 0, fields[i][0], 0 );
if ( pszFieldValue )
poDS->SetMetadataItem(fields[i][1], pszFieldValue);
}
break;
}
}
}
/* -------------------------------------------------------------------- */
/* Initialize any PAM information. */
/* -------------------------------------------------------------------- */
poDS->SetDescription( poOpenInfo->pszFilename );
poDS->TryLoadXML();
return( poDS );
}
