Description
This projection is used by geostationary satellites that are returning data located by the satellites' scanning angles. Two variants exist based on the main scanning direction of the viewing instrument onboard. It is used by Geostationary Operational Environmental Satellite R (GOES-R) series and Meteosat series of geostationary meteorological satellites.
The geostationary satellite projection is available in ArcGIS Pro 2.1 and later and in ArcGIS Desktop 10.6 and later.
Projection properties
The subsections below describe the geostationary satellite projection properties.
Graticule
Geostationary satellite is an azimuthal projection. It displays less than one hemisphere. The equator is always a horizontal straight line in the middle of projection. The central meridian is straight line, perpendicular to the equator at the nadir of the satellite, which is the center of the projection. The other meridians are unequally spaced and concave toward the central meridian. The parallels are also unequally spaced, but concave toward the equator. The poles and the meridians 90° away from the central meridian are never displayed. The amount of the hemisphere displayed depends on the height parameter. The graticule is symmetric across the equator and the central meridian.
Distortion
The geostationary satellite projection is neither conformal nor equal-area. It generally distorts shapes, areas, distances, directions, and angles. Only the center of the projection is free of distortion when scanning angles are multiplied with the satellite's height. Distortion increases away from the center. Extreme distortion exists near the edge of the map outline.
Usage
The geostationary satellite projection is used by geostationary meteorological satellites for data referenced with satellite's scanning angles. For correct display in ArcGIS, scanning angles are multiplied by the satellite's height to obtain the linear projected coordinates.
Limitations
The geostationary satellite projection is limited to less than a hemisphere. The range depends on the height parameter. The farther the satellite's nadir point is, the larger the portion of a hemisphere is displayed. This projection never shows poles or meridians 90° away from the central meridian.
Parameters
Geostationary satellite parameters are as follows:
- False Easting
- False Northing
- Longitude of Center
- Height
- Option, used to specify the main scanning direction of the on-board viewing instrument. The following values are available:
- 0 = The elevation angle is north to south, and the scanning angle is east to west. Used by GOES-R series of satellites.
- 1 = The elevation angle is east to west, and the scanning angle is north to south. Used by Meteosat series of satellites.
Sources
GOES-R Product Definition and User's Guide (PUG), Volume 3: Level 1B Products, Revision F (2017). Available online: https://www.goes-r.gov/users/docs/PUG-L1b-vol3.pdf [accessed on 2 October 2018].
Coordination Group for Meteorological Satellites (1999). LRHIT/HRIT Global Specification. Available online: https://www.cgms-info.org/documents/pdf_cgms_03.pdf [accessed on 2 October 2018].