The ground track oblique Cassini projection used for producing VIIRS mapped imagery

Stephen Mills

doi:10.1117/12.2060760

2 October 2014 The ground track oblique Cassini projection used for producing VIIRS mapped imagery

Stephen Mills

Proceedings Volume 9218, Earth Observing Systems XIX; 92180C (2014) https://doi.org/10.1117/12.2060760
Event: SPIE Optical Engineering + Applications, 2014, San Diego, California, United States

Abstract

The Suomi-NPP Visible Infrared Imager Radiometer Suite (VIIRS) radiance is mapped to make image products using the ground-track Mercator (GTM) algorithm developed at Raytheon. This algorithm defines a process for transforming gridded map (x/y) coordinates of the image into Earth coordinates (longitude/latitude). The y-axis reference is the satellite ground track, which is mapped with an even scale. Great circles placed orthogonally with respect to the ground track define the x-axis. In its current state the algorithm is only defined for the Map-to-Earth (MtE) transformation, but the Earth-to-Map (EtM) transformation has no mathematical algorithm, and instead must use a slow search algorithm for every point. Because of this, the GTM is not a true map projection. This paper remedies this by describing an EtM transformation algorithm using a Ground Track Oblique Cassini (GTOC) projection. This is in somewhat similar to the Space Oblique Mercator (SOM) Projection developed for Landsat. However, Landsat has a very narrow swath, and the GTOC projection better preserves scale across a wider swath, making it more suited for sensors such as VIIRS. Also, unlike the SOM, it keeps the ground-track centered, which is a more efficient use of screen area when it is viewed. This paper describes details of the algorithm, including adjustments necessary for an elliptical orbit and an ellipsoidal Earth. It evaluates Map parameters including conformality and scale preservation, comparing this with other projections, including the SOM. It also evaluates improvements in efficiency relative to a search algorithm.

Citation Download Citation

Stephen Mills "The ground track oblique Cassini projection used for producing VIIRS mapped imagery", Proc. SPIE 9218, Earth Observing Systems XIX, 92180C (2 October 2014); https://doi.org/10.1117/12.2060760

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available