EVOLUTION-MANAGER

Edit File: frmt_nitf.html

<html>
<head>
<title>NITF -- National Imagery Transmission Format</title>
</head>

<h1>NITF -- National Imagery Transmission Format</h1>

GDAL supports reading of several subtypes of NITF image files, and writing
simple NITF 2.1 files. NITF 1.1, NITF 2.0, NITF 2.1 and NSIF 1.0
files with uncompressed, ARIDPCM, JPEG compressed, JPEG2000 (with Kakadu, ECW SDKs or other JPEG2000 capable driver)
or VQ compressed images should be readable.

The read support test has been tested on various products,
including CIB and CADRG frames from RPF products, ECRG frames, HRE products.

Color tables for pseudocolored images are read. In some cases nodata values
may be identified.

Lat/Long extents are read from the IGEOLO information in 
the image header if available. If high precision lat/long georeferencing 
information is available in RPF auxilary data it will be used in preference 
to the low precision IGEOLO information. In case a BLOCKA instance is found, 
the higher precision coordinates of BLOCKA are used if the block data covers 
the complete image - that is the L_LINES field with the row count for that 
block is equal to the row count of the image. Additionally, all BLOCKA 
instances are returned as metadata. If GeoSDE TRE are available, they will be
used to provide higher precision coordinates.

Most file header and image header fields are returned as dataset level
metadata.

<h2>Creation Issues</h2>

On export NITF files are always written as NITF 2.1 with one image
and no other auxilary layers. Images are uncompressed by default, but JPEG
and JPEG2000 compression are also available. Georeferencing can only be written for 
images using a geographic coordinate system or a UTM WGS84 projection. Coordinates are implicitly 
treated as WGS84 even if they are actually in a different geographic coordinate
system. Pseudo-color tables may be written for 8bit images.

In addition to the export oriented CreateCopy() API, it is also possible to
create a blank NITF file using Create() and write imagery on demand. However,
using this methology writing of pseudocolor tables and georeferencing is
not supported unless appropriate IREP and ICORDS creation options are supplied.

Creation Options:

<ul>

<li> Most file header, imagery header metadata and security fields can
be set with appropriate creation options (although they are reported as metadata
item, but must not be set as metadata). For instance setting 
<tt>"FTITLE=Image of abandoned missle silo south west of Karsk"</tt> in the
creation option list would result in setting of the FTITLE field in the NITF
file header. Use the official field names from the NITF specification 
document; do not put the "NITF_" prefix that is reported when asking the metadata
list.

<li> IC=NC/C3/M3/C8 : Set the compression method.
<ul>
<li>NC is the default value, and means no compression.
<li>C3 means JPEG compression and is only available for the
CreateCopy() method. The QUALITY and PROGRESSIVE JPEG-specific
creation options can be used. See the <a href="frmt_jpeg.html">JPEG driver
documentation</a>. Starting with GDAL 1.7.0, multi-block images can be written.
<li>M3 is a variation of C3. The only difference is that a block map is written,
which allow for fast seeking to any block. (Starting with GDAL 1.7.0.)
<li>C8 means JPEG2000 compression (one block) and is available for 
CreateCopy() and/or Create() methods. JPEG2000 compression is only available
if the JP2ECW, JP2KAK or Jasper driver is available :
<ul>
<li> JP2ECW : The TARGET and PROFILE JP2ECW-specific creation options can be used.
Both CreateCopy() and/or Create() methods are available.
See the <a href="frmt_jp2ecw.html">JP2ECW driver documentation</a>.
<li> JP2KAK : The general JP2KAK-specific creation options can be used (QUALITY, BLOCKXSIZE, BLOCKYSIZE, GMLPJ2, GeoJP2, LAYERS, ROI).
Only CreateCopy() method is available.
See the <a href="frmt_jp2kak.html">JP2KAK driver documentation</a>.
<li>Starting with GDAL 1.7.0, if JP2ECW and JP2KAK drivers are not available, Jasper JPEG2000 driver can be used in the CreateCopy() case.
</ul>
</ul>
</li>

<li> NUMI=n : (Starting with GDAL 1.7.0) Number of images. Default = 1.
This option is only compatible with IC=NC (uncompressed images).

<li> ICORDS=G/D/N/S: Set to "G" to ensure that space will be reserved for
geographic corner coordinates (in DMS) to be set later via SetGeoTransform(), set to "D"
for geographic coordinates in decimal degrees, set to "N"
for UTM WGS84 projection in Northern hemisphere or to "S" for UTM WGS84 projection in
southern hemisphere (Only needed for Create() method, not CreateCopy()).
If you Create() a new NITF file and have specified "N" or "S" for ICORDS,
you need to call later the SetProjection method with a consistent
UTM SRS to set the UTM zone number (otherwise it will default to zone 0).

<li> FHDR: File version can be selected though currently the only 
two variations supported are "NITF02.10" (the default), and "NSIF01.00".

<li> IREP: Set to "RGB/LUT" to reserve space for a color table for
each output band. (Only needed for
Create() method, not CreateCopy()).

<li> IREPBAND: (GDAL >= 1.9.0) Comma separated list of band IREPBANDs in band order.

<li> ISUBCAT: (GDAL >= 1.9.0) Comma separated list of band ISUBCATs in band order.

<li> LUT_SIZE: Set to control the size of pseudocolor tables for
RGB/LUT bands. A value of 256 assumed if not present. (Only needed for
Create() method, not CreateCopy()).

<li> BLOCKXSIZE=n: Set the block width.

<li> BLOCKYSIZE=n: Set the block height.

<li> BLOCKA_*=: If a complete set of BLOCKA options is provided with 
exactly the same organization as the NITF_BLOCKA metadata reported when 
reading an NITF file with BLOCKA TREs then a file will be created with BLOCKA 
TREs.

<li> TRE=tre-name=tre-contents: One or more TRE creation options may 
be used provided to write arbitrary user defined TREs to the image header. The
tre-name should be at most six characters, and the tre-contents should be 
"backslash escaped" if it contains blackslashes or zero bytes. The argument
is the same format as returned in the TRE metadata domain when reading.

<li> FILE_TRE=tre-name=tre-contents: (GDAL >= 1.8.0) Similar to above options,
except that the TREs are written in the file header, instead of the image header.

<li> SDE_TRE=YES/NO: (GDAL >= 1.8.0) Write GEOLOB and GEOPSB TREs to get
more precise georeferencing. This is limited to geographic SRS, and to CreateCopy() for now.

</ul>

<h2>Links</h2>
<ul>
<li><a href="frmt_nitf_advanced.html">Advanced GDAL NITF Driver Information</a></li>
<li> <a href="http://www.gwg.nga.mil/ntb/">NITFS Technical Board Public Page</a></li>
<li> <a href="http://www.gwg.nga.mil/ntb/baseline/docs/digest/part2_annex_d.pdf">DIGEST Part 2 Annex D (describe encoding of NITF Spatial Data Extensions)</a></li>
<li> <a href="frmt_various.html#RPFTOC">RPFTOC</a> driver : to read the Table Of Contents of CIB and CADRG products.</li>
<li> <a href="http://www.everyspec.com/MIL-PRF/MIL-PRF+%28080000+-+99999%29/MIL-PRF-89038_25371/">MIL-PRF-89038</a> : specification of RPF, CADRG, CIB products</li>
<li> <a href="frmt_various.html#ECRGTOC">ECRGTOC</a> driver : to read the Table Of Contents of ECRG products.</li>
<li> <a href="http://www.everyspec.com/MIL-PRF/MIL-PRF+%28030000+-+79999%29/MIL-PRF-32283_26022/">MIL-PRF-32283</a> : specification of ECRG products</li>
</ul>

<h2>Credit</h2>

The author wishes to thank <a href="http://www.augsignals.com/">AUG
Signals</a> and the <a href="http://geoconnections.org/">GeoConnections</a>
program for supporting development of this driver, and to thank
Steve Rawlinson (JPEG), Reiner Beck (BLOCKA) for assistance adding features.

</body>
</html>