Long name Gokturk-1
Short name GK1
Sensor type

Optical high-resolution imager (HiRI)
Aperture: 65 centimeters
Focal length: 12.905 meters at f/20
Optics: Three-mirror anastigmatic (TMA)

  • Multispectral (MS), standard four-color: blue, green, red, near infrared (NIR)
  • Panchromatic (PAN)
Platform Gokturk-1
Key file name (use to open dataset) PM_GKT_GGS_*.xml
Supported file name extensions .xml, .tif, .jpg, .rpb

Data product name and description
Distribution disk files
Returned data for supported format

Data product name and description

Gokturk-1 is an Earth-observation satellite of the Turkish Ministry of National Defence. The HiRI instrument on Gokturk-1A is coupled with a data processing and x-band downlink system. The objective of the Gokturk-1 satellites is to provide high-resolution MS and PAN imagery with high-accuracy geolocation by using a pushbroom-imaging concept and recording the image strip swept by the orbital motion of the satellite. The imagery is delivered with multispectral resolution of 2 meters and panchromatic resolution of 0.5 meters in a swath width of 20 kilometers.

Note: The information provided herein is based on the data distributor's documentation cited under References.

Spectral bands:
Spectral range (nm)

Spatial resolution (m)*
(spectral resolution)

Maximum image dimensions
(Across track x along track, km)


B1 (Blue): 450-530
B2 (Green): 510-590
B3 (Red): 620-700
B4 (NIR): 775-915
PAN: 480-820

MS: 2.0
PAN: 0.5

20 kilometer, 60 degrees field of regard (FOR).
The satellite can collect imagery anywhere within a ground strip 800 kilometers wide, covering 200 kilometers in 11 seconds or 800 kilometers in 25 seconds, including stabilization time.


* Resolution is always nadir position unless noted otherwise.

Of the available Gokturk-1 product types, only L2A product is tested and supported by PCI software.

L2A data includes data as strip, strip stereo, triple set and wide area.

Processing level Horizontal accuracy (m) Description/notes
L2A   The product is a geometrically corrected ("perfect sensor") image, the first delivered product from the processing chain representing a single image. L2A is derived from L1 and corrected for radiometric and optical distortion due to the geometry of the internal sensor. The raw position of an L2A image, with respect to the reference ellipsoid, is given by the geographical coordinates of its bounding box (four corners and the center), computed using a coarse digital elevation model (DEM) (SRTM/Globe). The L2A image product includes the sensor models and is intended for subsequent photogrammetric processing, such as orthorectification.

Distribution disk files

A Gokturk-1 data set is organized in a specific folder structure on disk. GDB uses this folder structure and the file names to identify the data product type.

Warning: Data sets for this sensor are organized in a specific folder structure on disk. GDB uses this structure and the file names to identify the data product type. Do not alter the folder structure or any file names prior to data ingestion to ensure the image data and auxiliary information are imported correctly.

You can open a Gokturk-1 data set by selecting the PM_GKT_GGS_*.xml file.

When opening a Gokturk-1 data set to run in CATALYST Professional, you will be prompted to select the MS or PAN data you want.

When opening a data set in a CATALYST Professional algorithm or command-line application, such as EASI, you must include the -MS or -PAN designator, as applicable, with the file name extension.

For example:

When opening a Gokturk-1 data set, the files read by GDB are as described in the following table.

File name Format Required Contents/details
PM_GKT_GGS_*_L2A.xml Extensible Markup Language Yes Key file name, contains data set metadata.


GeoTIFF Yes Image data.
PREVIEW.tif Tagged Image File Format (TIFF) Yes Image thumbnail file.

Returned data for supported format

Gokturk-1 data can be opened directly in its raw vendor format or imported into a PCIDSK (*.pix) file using the key file name (PM_GKT_GGS_*.xml). For optimal processing, use the PCIDSK format.

The following table describes the data structure after it is opened by GDB.

Data product Data returned Details

1 x [16U] raster channel

1 x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [BIN] Rational function model

L2A (MS)

4 x [16U] raster channels

1 x [TEX] main product annotation
1 x [ORB] orbit segment
1 x [BIN] rational function model



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