Geometric processing levels

Learn about primary, georectified, and orthorectified geometric processing levels.


Overview

Processing is essential for transforming raw geospatial data into meaningful imagery. Processing levels act as a framework for understanding the level of transformation and manipulation the data has undergone. To select the right data for your use case, it is important to understand the processing levels offered.

Types of levels

Optical imagery falls into three geometric processing levels: primary, georectified, and orthorectified.

Primary

Primary imagery is closest to the natural image acquired by the sensor. The resulting imagery isn’t georeferenced nor orthorectified, and is used as a key component of digital elevation model (DEM) generation and orthorectification. It accounts for distortions caused by the optics and electronics of the sensor, as well as its ephemeris.

Primary imagery allows for meaningful analysis while remaining close to the raw form of the data.

Georectified

Georectified imagery is first calibrated and then georectified. Georectification adjusts imagery to align with an existing coordinate reference system. This ensures that features in the image correspond accurately to their geographic locations. There are two levels of georectification:

  • Coarse georeferencing, that applies an average terrain height for the area of interest is applied across the image.
  • Precise georeferencing, that applies terrain correction by referencing the image against a series of ground control points.

This is a mandatory step before using imagery in GIS software for accurate spatial analysis.

Orthorectified

Orthorectified imagery is first georectified and then orthorectified. Orthorectification removes distortions caused by terrain variations, camera angle, and other factors. The resulting orthorectified image will appear as if it was captured from directly above the region.

This correction enables accurate measurements and comparisons in geographic analysis.

Availability

Tasking collections

CollectionPrimaryGeorectifiedOrthorectified
AxelGlobeNot supported inline-icon-largeNot supported inline-icon-largeSupported inline-icon-large
Level 1C
Level 2A
Beijing-3ASupported inline-icon-large
Level 1
Supported inline-icon-large
Level 2A
Not supported inline-icon-large
Beijing-3NSupported inline-icon-large
Level 1
Supported inline-icon-large
Level 2
Not supported inline-icon-large
BlackSkyNot supported inline-icon-largeSupported inline-icon-largeSupported inline-icon-large
EROS-BSupported inline-icon-large
Level 1A
Supported inline-icon-large
Level 1B
Not supported inline-icon-large
EROS-CSupported inline-icon-large
Level 1A
Supported inline-icon-large
Level 1B
Not supported inline-icon-large
GEOSAT 1Not supported inline-icon-largeSupported inline-icon-largeSupported inline-icon-large
GEOSAT 2Not supported inline-icon-largeSupported inline-icon-largeSupported inline-icon-large
KOMPSAT-3Supported inline-icon-large
Level 1R
Supported inline-icon-large
Level 1O
Supported inline-icon-large
Level 1G
KOMPSAT-3ASupported inline-icon-large
Level 1R
Supported inline-icon-large
Level 1O
Supported inline-icon-large
Level 1G
Near Space LabsNot supported inline-icon-largeSupported inline-icon-largeNot supported inline-icon-large
PléiadesSupported inline-icon-largeSupported inline-icon-largeSupported inline-icon-large
Pléiades NeoSupported inline-icon-largeSupported inline-icon-largeSupported inline-icon-large
SatellogicNot supported inline-icon-largeNot supported inline-icon-largeSupported inline-icon-large
Level 1
Level 3
SPOTSupported inline-icon-largeSupported inline-icon-largeSupported inline-icon-large
TripleSatSupported inline-icon-large
Level 1
Supported inline-icon-large
Level 2
Not supported inline-icon-large
Vision-1Not supported inline-icon-largeSupported inline-icon-largeSupported inline-icon-large

Catalog collections

At least one geometric processing level per collection is always available on the console, but the availability of other levels may differ depending on the collection. Some levels are only available upon request.

CollectionPrimaryGeorectifiedOrthorectified
Beijing-3ASupported inline-icon-large
Level 1
Supported inline-icon-large
Level 2A*
Supported inline-icon-large
Level 4*
Level 4A*
EROS-BSupported inline-icon-large
Level 0A
Level 1A
Supported inline-icon-large
Level 1B
Not supported inline-icon-large
EROS-CSupported inline-icon-large
Level 0A
Level 1A
Supported inline-icon-large
Level 1B
Not supported inline-icon-large
Hexagon AerialNot supported inline-icon-largeNot supported inline-icon-largeSupported inline-icon-large
Landsat 8Not supported inline-icon-largeNot supported inline-icon-largeSupported inline-icon-large
Level 2SP
PléiadesSupported inline-icon-large*Supported inline-icon-large*Supported inline-icon-large
Pléiades NeoSupported inline-icon-large*Supported inline-icon-large*Supported inline-icon-large
Sentinel-2Not supported inline-icon-largeNot supported inline-icon-largeSupported inline-icon-large
Level 2A
SPOTSupported inline-icon-large*Supported inline-icon-large*Supported inline-icon-large
TripleSatNot supported inline-icon-largeSupported inline-icon-large
Level 2
Not supported inline-icon-large
Vexcel AerialNot supported inline-icon-largeSupported inline-icon-large
Oblique
Supported inline-icon-large
Ortho
True Ortho

*Upon request.

Troubleshooting

What is an RPC file?

Rational polynomial coefficients (RPCs) are parameters used to model the relationship between the pixels within the imagery and their corresponding geographic coordinates on the Earth’s surface. It takes into account the various geometric distortions, sensor characteristics, and Earth’s curvature effects to allow accurate transformation between image and geographic coordinates.

An RPC file is typically delivered alongside imagery of the primary processing level and can be used for subsequent processing steps like generating DEMs.

Learn more