Add MODIS NDVI data

[sdtaylor]

A discussion to chat about adding MODIS data to the retriever since I'm not sure if it's feasible or not. I just wrote a quick python script to download 250m_NDVI for all the dates for north america and there are some things to consider.

1. Many different products from landcover, veg indices, and raw reflectance, all at different spatial and temporal resolutions.
2. Non-static filenames. NASA will occasionally update things retroactively which then changes the filenames. For example the file http://e4ftl01.cr.usgs.gov/MOLT/MOD13Q1.005/2000.09.29/MOD13Q1.A2000273.h03v07.005.2008202152313.hdf is a file for the year 2000 but the 2008202152313 means it was processed in 2008. They may go back and re-do things and thus break any filenames stored.
3. New data always being added. Depending on the product it can take a few weeks for the most recent images to be put up.
4. It's in HDF format which is a pain to deal with. Ideally all the different tiles can be stiched together and converted to tif.
5. There's a lot of data. For the 250m bimonthly NDVI one date for north america is ~4.5GB. So a full year is ~100GB.

[sdtaylor]

"6". The usgs server that hosts all modis data now requires a login.

[ethanwhite]

"6". The usgs server that hosts all modis data now requires a login.

Arg. Do they allow access via API keys?

[sdtaylor]

Doesn't look like it at the moment. But it looks like they do have API access for other things. So maybe a possibility in the future.