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I am doing a household survey in Kenya, and I need to ensure that my survey team visits every house within a given area. I've been going to google maps and right-clicking on roofs to get coordinates via the "what's here" option. This is really an inefficient use of time.

I'd prefer to have a high-resolution image that I could upload to google earth engine, and then perform a machine-learning algorithm to identify roofs. I'd want to get a text file of the lat/longs of all the houses, which I could then cluster by distance and give to my surveyors, both in map and in checklist format.

But the images in google maps satellite view are copyrighted and not available in earth engine. So I need images at high-enough resolution to identify corrugated iron and straw thatch roofs, with roughly ~3km^2 spatial extent.

What are some good sources for such data? Ideally that will give it freely or cheaply to graduate students and/or nonprofits?

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    Have you looked at earthexplorer.usgs.gov This site contains high resolution OrbView data. I'm not 100% sure about the licensing though. May 22, 2013 at 6:31
  • Thanks for the comment. Unless I'm doing something wrong with the interface, it doesn't look like orbview has images for the places where I'm working. May 22, 2013 at 6:40
  • Even I'm getting the same result. Looks like this data isn't present in your area of study. :-( May 22, 2013 at 6:57
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    I'm going to assume that a house with a corrugated iron or straw thatch roof can be assembled quite quickly, in which case you need to be mindful of data currency. For example I have previously seen data in Google Earth that is > 5 years out of date
    – tomfumb
    Jul 14, 2013 at 22:55

5 Answers 5

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At the moment it's the best to use Landsat-8, Sentinel-2 (free non commercial use). Others are not so helpful.

Sources for non-commercial use:

  • You can get from Sentinel data hub such satellites Sentinel-1A, 1B, 2 and more in future.
  • You can get many from EarthExplorer. As example it's Landsat 7,8 and etc, ASTER, EO-1 and etc. Additional sources for ASTER Asterweb.jpl.nasa.gov
  • Many data in ESA include high resolutions satellite. It's impossible to enumerate. There many satellites, but it's necessary to provide project for access to the data. How to access EO data
  • Also from Alaska Satellite Facility. These data are based on the Synthetic Aperture Radar (SAR) satellities, but they can be analyzed in some issues (as example flood detection)
  • NASA Reverb. There's a lot of data, it's difficult to navigate. Tutorial
  • National Institute for Space Research (INPE) dgi.inpe.br CBERS images
  • Indian Geo-Platform of ISRO bhuvan.nrsc.gov.in
  • Roscosmos Geoportal gptl (Alos, Ikonos, Geoeye, Formosat, SPOT, Quickbird, Rapideye, Terra, Worldview and etc) And SPOT images kosmosnimki.ru
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You might want to checkout the MapBox Satellite layer. It's available under their Basic Plan, which is $5 a month. I believe the layer is distributed as TMS tiles, and you can review the granularity and coverage of the layer before you commit to anything.

Admittedly, though, this would be more difficult to apply to your use case, but surely not impossible, as GDAL could be used to mosaic the tiles.

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Not exactly "high-resolution," but the price is right.

Esri's World Imagery map service presents satellite imagery for the world and high-resolution imagery for the United States and other areas around the world.

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One place to look for imagery sources is OpenStreetMap's "editor imagery index", which is basically a machine readable list of imagery provider URLs and extents.

https://github.com/osmlab/editor-imagery-index

The needs of your project aren't exactly the same as OSM's but there is overlap. In this case, in the Nairobi region it shows Bing and Mapbox Satellite. At their maximum zooms, Bing looks like:

enter image description here

and Mapbox Satellite:

enter image description here

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The SpaceNet corpus provides both high resolution satellite imagery and labeled building footprints.

https://aws.amazon.com/public-datasets/spacenet/

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