PlanetScope and Rapid Eye: Asset Type and Band Classification from Planet Labs

Question

I have been trying to get weekly downloads for a region of interest from the PLANET API and I had a couple of questions regarding the asset types

• I have been consistently getting much less number of PlanetScope OrthoTile Analytic(PSOrthoTile Analytic) compared to Rapid Eyes OrthoTile Analytic(REOrthoTile) for the same time periods. If I understand it correctly and the same areas are being mapped everyday shouldn't I get a consistent number of scenes from PSOrthoTile as well and much more. Am I missing something here, should I be looking into different asset type instead of using "PSOrthoTile Analytic" or "REOrthoTile Analytic" to include NIR band and daily imagery?

• The REOrthoTile seems to be calibrated meaning I can generate False Color Composites and derive indices from the RE product however for the PSOrthoTile Analytic is the 4th Band NIR because I cannot seem to create a FCC or do any band math using existing setup such as NDVI for example since the value is pure DN and stretched upto the 16bit maxima.

I look forward to some insight and maybe someone has a working example they would like to share.

After clarification on the first point, I do understand that RE has been functional much longer and hence their archival data is richer for older time periods. In terms of Analytic versus Visual imagery I wanted to point out that I downloaded both analytic and visual imagery and they both seem to have only 3 bands and one transparency band.

I have tried this with multiple scenes and target and standard selections within the analytic images. So you can see why there is the confusion. This means I have only 3 bands available within the analytic band which I cannot use to create false color composites or to perform NDVI. I look forward to your thoughts.The scenes id shown here is "20160803_013818_0c43_analytic" and visual from open California

Answer 1

1. There is no guarantee of similar numbers of PSOrthoTile items for a given geography and time range as there are REOrthoTiles. REOrthoTile history goes back much further than PSOrthoTiles. Also a lot depends on tasking priorities for the PlanetScope and RapidEye constellations. That said for recent time periods (last couple months) you should start seeing more PSOrthoTiles for many locations than REOrthoTiles.

2. The "analytic" PSOrthoTile asset is a radiance product similar to the REOrthoTile analytic product. The uncalibrated asset is called "analytic_dn". While we are still fine tuning the calibration for PlanetScope radiance products you should be able to produce NDVI and other indices that only depend on red, green, blue and ndvi from PSOrthoTiles. Note that the fifth band of PSOrthoTile products is Alpha (ie. a transparent mask). Do not try to use it in an index.

3. You mention 20160803_013818_0c43_analytic but this appears to be a PSScene3Band item, not a PSOrthoTile item based on the name - perhaps pulled from https://api.planet.com/data/v1/item-types/PSScene3Band/items/20160803_013818_0c43. There are several PSOrthoTile products with touch this scene including https://api.planet.com/data/v1/item-types/PSOrthoTile/items/215399_1055226_2016-08-03_0c43. I have activated the analytic products for that orthotile, downloaded it and confirmed is has five bands (Blue, Green, Red, NIR, Alpha). I checked them in QGIS and they looked reasonable.