Pixel Raster Space for Coordinate Grid on Sentinel 3/2 and Coordinate Delta

Optical Toolbox
#1

Hello!

I was reading OpenGeoSpatial Documentation about the Pixel Raster Space and I got 2 important questions from it

  1. Is the coordinate grid from the file ‘geo_coordinates.nc’ in the center or the top-left corner of the pixel

  2. Why is the coordinate grid non-homogeneous. This means that if I take the difference in coordinates from 1 place in the grid to the next (both vertically and horizontally) the Coordinate-Delta changes along the grid. I would guess because the curvature of the earth but, isn’t that compensated with the Orthographic projection?

Thanks!
Alvaro

#2

Hello Alvaro,

The coordinates refer to the pixel centre. And the different distance result from the fact that the data is not reprojected. They are still in satellite raster. The lat/lon values are orthorectified but not projected. This means that the difference can be even higher. You can see this especially in mountainous areas.

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#3

Thanks for the quick response :slight_smile: