Sentinel-1 time series: how selecting orbit number

openEO Platform
1

Hello everyone,

I am new to this forum and excited to engage with the community here. My current work involves analyzing time series data from Sentinel-1 satellites, with a focus on implementing my REACTIV change detection algorithm within the OPENEO platform.

I have a question regarding selecting specific orbit numbers to create a time series from the same orbital tube. Currently, I can filter the collection by ascending orbits using the following code snippet:
python

s1_cube = connection.load_collection(
    "SENTINEL1_GRD",
    temporal_extent=("2019-06-01", "2020-01-01"),
    spatial_extent=bbox_aoi,
    bands=['VH', 'VV'],
    properties=[
        openeo.collection_property("sat:orbit_state") == "ASCENDING",
    ],
)

However, I am looking for a way to select images based on a specific orbit number, and I haven’t found the appropriate property. Does anyone have experience with this or could guide how to filter by orbit number within OPENEO?

Thank you in advance for your assistance!

2

Hi Elise,

Unfortunately, at the moment this is not possible. We can look into supporting the sat:absolute_orbit and sat:relative_orbit properties; would this cover it?

How urgent is this?

Cheers,
Jan

3

Hi Jan,

Yes, that would cover the need perfectly! Supporting the sat:absolute_orbit and sat:relative_orbit properties would be highly beneficial, especially for handling radar time series. Selecting a common orbital path is crucial to avoid mixing different orbits and ensure consistent geometric configuration (incidence). My main objective is to manage the REACTIV algorithm through OpenEO. It has already been successfully implemented in EO Browser (see this article).

As for the urgency, it’s difficult to give a precise timeline, but my goal is to republish a version of this algorithm using both polarizations by the end of the year for a special issue on Sentinel-1. If I can integrate it with OpenEO, I would be more than happy to include it, otherwise, I’ll have to proceed without it :sweat_smile:.

4

Hi Elise,

You can track the progress of this issue here: SENTINEL1_GRD: support filtering by orbit number · Issue #339 · Open-EO/openeo-geotrellis-extensions · GitHub

Cheers,
Jan