AREA_OR_POINT in Sentinel-2 JP2 Files

s2tbx
#1

Dear all,

I am currently wondering how the raster data model of the OpenJPEG2000 files in which the Sentinel-2 data (L1C + L2A) is stored treats the ‘AREA_OR_POINT’ issue. My suspicion is that the ‘AREA_OR_POINT’ metadata is ‘POINT’, i.e., the pixel coordinates relate to the pixel’s center and not to its upper left corner (Area). However, apart from this discussion here (amazon web services - Does the origin of Sentinel-2 L1C images on AWS represent a point at the center of the pixel or a point at the upper left corner? - Geographic Information Systems Stack Exchange) I was not able to find an official proof for that - also not in the Sentinel-2 Products Specification Document.

Maybe this question has already been asked before and answered. I also haven’t checked the gml in the JPEG2000 header so far because I was hoping there must be an easier way (documentation) to get an answer to my question.

Thanks for your help!
Cheers, Lukas

1 Like
#2

Hi all again, is there really NO answer to this question? I mean it’s actually a very relevant point - so I am actually a bit puzzled about the silence (I hope it’s not a bad sign)

#3

Hello @lukasValentin

The Upper Left of the Tile is the anchor point. Section 4.9.2 of the [PSD] refers. I would also note that this question should not be asked here; it’s more a question that should be raised to EOSupport@Copernicus.esa.int

Cheers

Jan

Jan Jackson

OPT-MPC S2 Technical Manager

#4

Hi @Jan, thanks for the clarification.

Just as a side note: From my point of view such questions - which might also be relevant to other users although being very technical - should be asked in a way also others can benefit from the answer(s); I don’t really see how this should work out when writing an e-mail with only me and someone from ESA involved. Just as a suggestion for future improvements of information dissemination…

Best
Lukas

1 Like
#5

hi @Jan and @lukasValentin, I’m running into this same problem/question, the header does not specify whether PixelIsPoint or PixelIsArea is used to define the pixel coordinates. The answer above doesn’t really provide an answer as in both cases the tile is anchored to the coordinates of the upper-left pixel, but are these the coordinates of the center of the pixel or its top-left corner? Thanks for clarifying this.
Cheers, Kilian

#6

I’ve recently raised a very similar issue for Sentinel-1 GRD products and S-1 MPC is trying to find an answer for that. Did you find an answer for Sentinel-2 tiles?