OpenStreetMap

what are these oddly shaped circular features?

Posted by rayKiddy on 17 October 2014 in English (English)

I am editing in HOT task “#672 - Ebola Outbreak, Port Loko, Bombali districts, road network”, and I am seeing these odd somewhat circular features on the ground. This screenshot is about 600 ft (180 m) wide. Groups of them look a bit like honeycombs. What are these?

I suspect that they are man-made and are something agricultural, but I am also not seeing buildings nearby. So, it is not clear. The line is a tertiary road and probably not paved. Any guesses?

several groups of unknown circular features

Comment from BCNorwich on 18 October 2014 at 07:10

Hi. A link to the area of your screenshot would help, also what is the image layer, please? Looking close at your image I would suggest that the larger blobs are palm trees you can just make out fronds. Each throwing a shadow to the SSW, the shadow of the trunks are also visible. As to the smaller lighter blobs they are shaded to the SSW side suggesting they are not high enough to cast a remote shadow on the ground. The blobs also seem to be equally spaced. Yes I think some form of agriculture. Regards

Comment from Sanderd17 on 18 October 2014 at 13:54

It could also be the work of termites. I don’t know which (if any) termites live in that region, but some sorts of termites are able to create surprisingly regular patterns in their mounds.

Comment from GEOSPEX on 19 October 2014 at 00:26

Hi rayKiddy, Several people in NYC for ebola mapping were in this tile today, and it did come up in discussion. Since this pattern shows up across this particular tile and others nearby, it seems likely that it is agriculturally related; that is, some type of crop on attended terrain. Exactly what that crop is, verdict still out.

Comment from Firefishy on 19 October 2014 at 12:49

It is most likely agricultural of some sort. At a guess each circle is land cleared to tend to a single plant… Cassava or other tuber.

Comment from kucai on 20 October 2014 at 01:21

my guess would be a cemetery. (really, not a spin on the ebola thing)

Comment from Vincent de Phily on 20 October 2014 at 08:43

I’ve usually mapped those as orchards. They’re a bit too low for palm trees. My guess is pineapple, but don’t quote me on that.

As for there being no paths to reach the area, remember that main access is by foot and is often not visible from imagery.

Comment from rayKiddy on 22 October 2014 at 22:05

Someone mentioned these in an e-mail to a HOT list. It is apparently cassava.

See:

If you want, could take a look also at this aerial photo of cassava and its footnote (or others): [http://www.gettyimages.com/detail/photo/bangweulu-floodplain-zambia-aerial-view-of-high-res-stock-photography/72886297]

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