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Can a model trained on satellite data really find brambles on the ground?

178 points| sadiq | 5 months ago |toao.com

53 comments

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cuno|5 months ago

So after transforming multispectral satellite data into a 128-dimensional embedding vector you can play "Where's Wally" to pinpoint blackberry bushes? I hope they tasted good! I'm guessing you can pretty much pinpoint any other kind of thing as well then?

avsm|5 months ago

Yes it's very good fun just exploring the embeddings! It's all wrapped by the geotessera Python library, so with uv and gdal installed just try this for your favourite region to get a false-colour map of the 128-dimensional embeddings:

  # for cambridge
  # https://github.com/ucam-eo/geotessera/blob/main/example/CB.geojson
  curl -OL https://raw.githubusercontent.com/ucam-eo/geotessera/refs/heads/main/example/CB.geojson
  # download the embeddings as geotiffs
  uvx geotessera download --region-file CB.geojson -o cb2
  # do a false colour PCA down to 3 dimensions from 128
  uvx geotessera visualize cb2 cb2.tif
  # project onto webmercator and visualise using leafletjs over openstreetmap
  uvx geotessera webmap cb2.tif --output cb2-map --serve
Because the embeddings are precomputed, the library just has to download the tiles from our server. More at: https://anil.recoil.org/notes/geotessera-python

Downstream classifiers are really fast to train (seconds for small regions). You can try out a notebook in VSCode to mess around with it graphically using https://github.com/ucam-eo/tessera-interactive-map

The berries were a bit sour, summer is sadly over here!

Waterluvian|5 months ago

I haven’t done this kind of thing since undergrad, but hyperspectral data is really frickin cool this way. Not only can you use spectral signatures to identify specific things, but also figure out what those things are made out of by unmixing the spectra.

For example, figure out what crop someone’s growing and decide how healthy it is. With sufficient temporal resolution, you can understand when things are planted and how well they’re growing, how weedy or infiltrated they are by pest plants, how long the soil remains wet or if rainwater runs off and leaves the crop dry earlier than desired. Etc.

If you’re a good guy, you’d leverage this data to empower farmers. If you’re an asshole, you’re looking to see who has planted your crop illegally, or who is breaking your insurance fine print, etc.

sadiq|5 months ago

Yes! TESSERA is very new so we're still exploring how well it works for various things.

We're hoping to try it with a few different things for our next field trip, maybe some that are much harder to find than brambles.

0_____0|5 months ago

I've wondered this about finding hot springs.

NedF|5 months ago

> Can a model trained on satellite data really find brambles on the ground?

No, as per researcher, "However, it is obvious that most of the generated findings aren’t brambles" and obviously no.

All the model did was think they followed roads, all roads.

If it was oil and gas where people put in effort and their results where checked vs universities where meaningless citations matter and results are never confirmed, it would be more believable.

What they are asking is impossible, increasing the likelihood without silly hacks like it's not in rivers or on top of buildings is an interesting problem but out of scope for academics.

sadiq|5 months ago

I was a lot more optimistic about Gabriel's model than he was. It is essentially a presence-only species distribution model where accuracy depends largely on assumptions around prevalence and which really needs some presence-absence data to calibrate.

As I mentioned in one of the other comments, the model is also only pixel-wise. That is, it is not using spatial information for predictions.

xarope|5 months ago

isn't this the same findings as the old "we trained to identify huskies, but instead we identified snow" problem?

whalesalad|5 months ago

FarmLogs (YC 12) did exactly this. We used sat imagery in the near-infrared spectrum to determine crop health remotely. Modern farming utilizes a practice called precision ag - where your machine essentially has a map of zones on the field for where treatments are or aren't needed and controllers that can turn spray nozzles on/off depending on boundaries. We used sat imagery as the base for an automated prescription system, too. So a farmer can reduce waste by only applying fertilizer or herbicide in specific areas that need it.

lloeki|5 months ago

Well looks like they found a lot of brambles! Were there large areas without any bramble?

Cue dowsers, who successfully find water... but also who would anyway anywhere else because underground water isn't the underground river/pocket that people imagine and thus random chance by itself has high probability of finding water.

sadiq|5 months ago

We did note several places during the trip that didn't contain bramble. The hotspot in the middle of the residential area was also entirely isolated.

For a proper evaluation you would need to be more methodological but as a sanity-check we were very happy with it.

One other thing to point out about the bramble model is that it is pixel-wise. That is each prediction is exclusively only what is within the 10 metre pixel (give or take the georeferencing error).

pbhjpbhj|5 months ago

Not much detail on the method? Like what data it takes from iNaturalist - for example if it's taking in GPS coordinates of observations of brambles then it's not clear what there is for the ML model to do.

What detail was in the satellite images, was it taking signals of the type of spaces brambles are in, or was it just visually identifying bramble patches?

In the UK you get brambles in pretty much every non-cultivated green space. I wonder how well the classifier did?

Interesting project.

sadiq|5 months ago

Hi! You can find a bit more about Gabriel's model through some of his posts over the last few weeks: https://gabrielmahler.org/posts/

When it comes to the satellite images, the model actually used TESSERA (https://arxiv.org/abs/2506.20380) which is a model we trained to produce embeddings for every point on earth that encodes the temporal-spectral properties over a year.

Think of it like a compression of potentially fifty or a hundred observations of a particular point in earth down to a single 128 dimension vector.

Happy to answer any other questions.

ensocode|5 months ago

We have a problem with Giant Hogweed and I was thinking about ways to identify hotspots. My guess is that standard satellite imagery, like Google Maps, probably isn’t good enough. To even check if this could work, you’d need high-res imagery (sub-meter), ideally multispectral, and some way to validate it on the ground. What steps should I take to verify if this is possible in a way this was done here?

sadiq|5 months ago

I would try https://github.com/ucam-eo/tessera-interactive-map , this is relatively easy to get started with and has a nice interface for labeling.

https://github.com/ucam-eo/geotessera has an image showing our embedding coverage at the moment. Blue areas we have complete coverage for 2024, green areas we cover 2017-2024. We're slowly trying to populate everything 2017-2024 but the constraint is GPU and storage at the moment - each year takes ~20k GPU/200k CPU hours and requires storing and serving 200 terabytes of data. The world is big!

If there is an area you would like prioritised, there's an issue template on the geotessera github repo which we can use to move regions around in the processing queue.

cjensen|5 months ago

The in-person verification of hotspots was good, but in-person verification of non-hotspots was not done, and might be difficult.

jcims|5 months ago

Seems like it could be pretty useful for archaeology as well.

sadiq|5 months ago

That's actually a great idea! I wonder what kind of feature size would be needed though - TESSERA's embeddings are at a 10 metre resolution so for larger structures you might need some kind of spatial aggregation.

folli|5 months ago

As a hobby project, I was looking into using LiDAR data to view archeological points of interest in Switzerland: https://github.com/r-follador/delta-relief

It would be interesting to overlay TESSERA data there, although the resolution is of course very different.

lightedman|5 months ago

A model I have trained on ASTER and LANDSAT data has major difficulties identifying spots for agate hunting. Even after I've given it extra instruction such as looking only in volcanic terrain (with USGS map provided,) or focusing on mixed signals of hydrous silica and iron, checking near known fault zones in said volcanic areas, it still gave me results everywhere, and almost none matching my criteria.

Plants are a way different and more difficult ballgame (they like to mess up my satellite data) so as I read I am not surprised to see that this didn't really give proper results.

ggm|5 months ago

If it can find sloes it's going to make sloe gin foragers very very angry. Generally when they find a usable crop they don't share it.

thinkingemote|5 months ago

Brambles are blackberries. Sloes are from Blackthorn bushes. They are different plants but probably are in the same location!

Peteragain|5 months ago

I read this and questioned the statistical methods 101. To say it works, one would also need to check for false positives. And such a check would pick up on "oh it's finding roads and there's a correlation between road and brambles."

themafia|5 months ago

> So it turns out that there's a lot of bramble between the community center and entrance to Milton Country Park.

> In every place we checked, we found pretty significant amounts of bramble.

[Shocked Pikachu face]

daemonologist|5 months ago

The whole-earth embeddings are interesting. Wonder if it'd be any good for looking for fresh water sources in the desert.

avsm|5 months ago

Are you thinking of _new_ fresh water sources that emerge in recent years? If you have any candidate lat/lon where this might have happened, we can take a look at the 2024 and earlier embeddings to see if we can spot it.

siva7|5 months ago

can it find me truffles?

sadiq|5 months ago

If you have some GPS locations of truffles, you could use the notebook Anil mentioned here https://news.ycombinator.com/item?id=45378855 and give it a go.

There is the issue of just how visible truffles are from space though, if they grow under cover. That said, it may still work because you can find habitats that are very likely to have truffles. We've had some promising results looking at fungal biomass.