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Reading NITF file using GDAL C++

I need to write a NITF file using GDAL C++ libraries. I am able to open the file but unable to read NITF header fields (e.g FTITLE, CLEVEL etc). If anybody is having a sample code, kindly post. Also, my code is:

GDALDataset*    poDataset;
GDALAllRegister();
poDataset = (GDALDataset *)GDALOpen("i_3001a.ntf", GA_ReadOnly);
if (poDataset == NULL)
{
  std::cout << "Unable to open the file" << std::endl;
  return 0;
}


printf("Driver: %s/%s\n",
    poDataset->GetDriver()->GetDescription(),
    poDataset->GetDriver()->GetMetadataItem(GDAL_DMD_LONGNAME));
printf("Size is %dx%dx%d\n",
    poDataset->GetRasterXSize(), poDataset->GetRasterYSize(),
    poDataset->GetRasterCount());



GDALDriver* poDriver = poDataset->GetDriver();

char** papszMetadata = NULL;
papszMetadata = poDataset->GetMetadata("NITF_METADATA");
if (papszMetadata == NULL)
{
    std::cout << "Unable to get metadata" << std::endl;
    return 0;
}

Now, how to extract the individual fields from the metadata. Also, help in reading image blocks. Any good site shall also help

Thanks

Solution

  • If you want just the standard NITF header fields, you can get the list of fields by calling...

    gdalinfo -mdd all 'i_3001a.ntf'

    That will give a big list of Key/Value pairs. The image you provided is from the DOD's reference page, so here is the output on that file...

    
Driver: NITF/National Imagery Transmission Format
Files: i_3001a.ntf
Size is 1024, 1024
Coordinate System is:
GEOGCRS["WGS 84",
    DATUM["World Geodetic System 1984",
        ELLIPSOID["WGS 84",6378137,298.257223563,
            LENGTHUNIT["metre",1]]],
    PRIMEM["Greenwich",0,
        ANGLEUNIT["degree",0.0174532925199433]],
    CS[ellipsoidal,2],
        AXIS["geodetic latitude (Lat)",north,
            ORDER[1],
            ANGLEUNIT["degree",0.0174532925199433]],
        AXIS["geodetic longitude (Lon)",east,
            ORDER[2],
            ANGLEUNIT["degree",0.0174532925199433]],
    ID["EPSG",4326]]
Data axis to CRS axis mapping: 2,1
Origin = (84.999999864233729,32.983333469099598)
Pixel Size = (0.000000271532530,-0.000000271532530)
Metadata:
  NITF_ABPP=08
  NITF_CCS_COLUMN=0
  NITF_CCS_ROW=0
  NITF_CLEVEL=03
  NITF_ENCRYP=0
  NITF_FBKGC=255,255,255
  NITF_FDT=19971217102630
  NITF_FHDR=NITF02.10
  NITF_FSCATP=
  NITF_FSCAUT=
  NITF_FSCLAS=U
  NITF_FSCLSY=
  NITF_FSCLTX=
  NITF_FSCODE=
  NITF_FSCOP=00000
  NITF_FSCPYS=00000
  NITF_FSCRSN=
  NITF_FSCTLH=
  NITF_FSCTLN=
  NITF_FSDCDT=
  NITF_FSDCTP=
  NITF_FSDCXM=
  NITF_FSDG=
  NITF_FSDGDT=
  NITF_FSREL=
  NITF_FSSRDT=
  NITF_FTITLE=Checks an uncompressed 1024x1024 8 bit mono image with GEOcentric data. Airfield
  NITF_IALVL=0
  NITF_IC=NC
  NITF_ICAT=VIS
  NITF_ICORDS=G
  NITF_IDATIM=19961217102630
  NITF_IDLVL=1
  NITF_IGEOLO=325900N0850000E325900N0850001E325859N0850001E325859N0850000E
  NITF_IID1=Missing ID
  NITF_IID2=- BASE IMAGE -
  NITF_ILOC_COLUMN=0
  NITF_ILOC_ROW=0
  NITF_IMAG=1.0 
  NITF_IMODE=B
  NITF_IREP=MONO
  NITF_ISCATP=
  NITF_ISCAUT=
  NITF_ISCLAS=U
  NITF_ISCLSY=
  NITF_ISCLTX=
  NITF_ISCODE=
  NITF_ISCRSN=
  NITF_ISCTLH=
  NITF_ISCTLN=
  NITF_ISDCDT=
  NITF_ISDCTP=
  NITF_ISDCXM=
  NITF_ISDG=
  NITF_ISDGDT=
  NITF_ISORCE=Unknown
  NITF_ISREL=
  NITF_ISSRDT=
  NITF_ONAME=JITC Fort Huachuca, AZ
  NITF_OPHONE=(520) 538-5458
  NITF_OSTAID=i_3001a
  NITF_PJUST=R
  NITF_PVTYPE=INT
  NITF_STYPE=BF01
  NITF_TGTID=
Metadata (DERIVED_SUBDATASETS):
  DERIVED_SUBDATASET_1_NAME=DERIVED_SUBDATASET:LOGAMPLITUDE:i_3001a.ntf
  DERIVED_SUBDATASET_1_DESC=log10 of amplitude of input bands from i_3001a.ntf
Metadata (NITF_METADATA):
  NITFFileHeader=000404 TklURjAyLjEwMDNCRjAxaV8zMDAxYSAgIDE5OTcxMjE3MTAyNjMwQ2hlY2tzIGFuIHVuY29tcHJlc3NlZCAxMDI0eDEwMjQgOCBiaXQgbW9ubyBpbWFnZSB3aXRoIEdFT2NlbnRyaWMgZGF0YS4gQWlyZmllbGRVICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIDAwMDAwMDAwMDAw////SklUQyBGb3J0IEh1YWNodWNhLCBBWiAgKDUyMCkgNTM4LTU0NTggICAgMDAwMDAxMDQ5NDc5MDAwNDA0MDAxMDAwNDk5MDAwMTA0ODU3NjAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDA=
  NITFImageSubheader=499 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
Metadata (CGM):
  SEGMENT_COUNT=0
Corner Coordinates:
Upper Left  (  84.9999999,  32.9833335) ( 85d 0' 0.00"E, 32d59' 0.00"N)
Lower Left  (  84.9999999,  32.9830554) ( 85d 0' 0.00"E, 32d58'59.00"N)
Upper Right (  85.0002779,  32.9833335) ( 85d 0' 1.00"E, 32d59' 0.00"N)
Lower Right (  85.0002779,  32.9830554) ( 85d 0' 1.00"E, 32d58'59.00"N)
Center      (  85.0001389,  32.9831944) ( 85d 0' 0.50"E, 32d58'59.50"N)
Band 1 Block=1024x1 Type=Byte, ColorInterp=Gray

    Then you can call them directly or in bulk...

    #include <iostream>
#include <gdal/gdal.h>
#include <gdal/gdal_priv.h>

int main( int argc, char* argv[] )
{
    GDALDataset*  poDataset;
    GDALAllRegister();
    poDataset = (GDALDataset *)GDALOpen("i_3001a.ntf", GA_ReadOnly);
    if (poDataset == NULL)
    {
        std::cout << "Unable to open the file" << std::endl;
        return 0;
    }

    printf( "Driver: %s/%s\n",
            poDataset->GetDriver()->GetDescription(),
            poDataset->GetDriver()->GetMetadataItem(GDAL_DMD_LONGNAME));
    printf( "Size is %dx%dx%d\n",
            poDataset->GetRasterXSize(), 
            poDataset->GetRasterYSize(),
            poDataset->GetRasterCount() );


    GDALDriver* poDriver = poDataset->GetDriver();

    char** papszMetadata = NULL;

    // Bulk Call
    papszMetadata = poDataset->GetMetadata( nullptr );
    if (papszMetadata == NULL)
    {
        std::cout << "Unable to get metadata" << std::endl;
        return 0;
    }
    else
    {
        int counter = 0;
        while( papszMetadata[counter] != nullptr )
        {
            std::cout << "Item: " << papszMetadata[counter] << std::endl;
            counter++;
        }
    }

    // Specific item
    std::cout << std::endl;
    std::cout << "NITF_ONAME: " << poDataset->GetMetadataItem( "NITF_ONAME" ) << 
    std::endl;


    return 0;
}

    Here is the output of this slight mod to your code...

    Driver: NITF/National Imagery Transmission Format
Size is 1024x1024x1
Item: NITF_ABPP=08
Item: NITF_CCS_COLUMN=0
Item: NITF_CCS_ROW=0
Item: NITF_CLEVEL=03
Item: NITF_ENCRYP=0
Item: NITF_FBKGC=255,255,255
Item: NITF_FDT=19971217102630
Item: NITF_FHDR=NITF02.10
Item: NITF_FSCATP=
Item: NITF_FSCAUT=
Item: NITF_FSCLAS=U
Item: NITF_FSCLSY=
Item: NITF_FSCLTX=
Item: NITF_FSCODE=
Item: NITF_FSCOP=00000
Item: NITF_FSCPYS=00000
Item: NITF_FSCRSN=
Item: NITF_FSCTLH=
Item: NITF_FSCTLN=
Item: NITF_FSDCDT=
Item: NITF_FSDCTP=
Item: NITF_FSDCXM=
Item: NITF_FSDG=
Item: NITF_FSDGDT=
Item: NITF_FSREL=
Item: NITF_FSSRDT=
Item: NITF_FTITLE=Checks an uncompressed 1024x1024 8 bit mono image with GEOcentric data. Airfield
Item: NITF_IALVL=0
Item: NITF_IC=NC
Item: NITF_ICAT=VIS
Item: NITF_ICORDS=G
Item: NITF_IDATIM=19961217102630
Item: NITF_IDLVL=1
Item: NITF_IGEOLO=325900N0850000E325900N0850001E325859N0850001E325859N0850000E
Item: NITF_IID1=Missing ID
Item: NITF_IID2=- BASE IMAGE -
Item: NITF_ILOC_COLUMN=0
Item: NITF_ILOC_ROW=0
Item: NITF_IMAG=1.0 
Item: NITF_IMODE=B
Item: NITF_IREP=MONO
Item: NITF_ISCATP=
Item: NITF_ISCAUT=
Item: NITF_ISCLAS=U
Item: NITF_ISCLSY=
Item: NITF_ISCLTX=
Item: NITF_ISCODE=
Item: NITF_ISCRSN=
Item: NITF_ISCTLH=
Item: NITF_ISCTLN=
Item: NITF_ISDCDT=
Item: NITF_ISDCTP=
Item: NITF_ISDCXM=
Item: NITF_ISDG=
Item: NITF_ISDGDT=
Item: NITF_ISORCE=Unknown
Item: NITF_ISREL=
Item: NITF_ISSRDT=
Item: NITF_ONAME=JITC Fort Huachuca, AZ
Item: NITF_OPHONE=(520) 538-5458
Item: NITF_OSTAID=i_3001a
Item: NITF_PJUST=R
Item: NITF_PVTYPE=INT
Item: NITF_STYPE=BF01
Item: NITF_TGTID=

NITF_ONAME: JITC Fort Huachuca, AZ

    WARNING: This doesn't work for Tagged-Record-Extensions (TREs), that requires a little more digging.