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bao18 / open_earth_map

Quick start in OpenEarthMap
MIT License
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Geographic Misalignment -- projection information for label data #3

Open JohnKilbride opened 1 year ago

JohnKilbride commented 1 year ago

Hello,

I wanted to ask about the projection information for the labels.

The label GeoTIFFs contain information with the EPSG:4326 CRS (WGS 84). When I render these with respect to other image datasets, I am seeing a misalignment. I tried playing around with linear displacements and it appears to require a more complex reprojection to account for the misalignment.

Based on Arxiv pre-print, I believe this is probably the result of precisely aligning the label with the reference imagery. Is that the case, or do I just have the projection data messed up?

Thank you! This is an incredible dataset!

bao18 commented 1 year ago

I appreciate your interest in our OpenEarthMap project. The GeoTIFF labels have the same projection as their corresponding reference satellite/aerial image (no misalignment between them). The reference images have the same projection as their sources (we didn't perform any re-projection or alignments). We also noticed that some source images are not perfectly aligned with other datasets. Most probably due to the different projections used between datasets, but in most cases, these misalignments are minor. The ones coming from xBD have the higher misalignment.