MODIS: Difference between revisions
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Two versions of HDF seem to be common: HDF4 and HDF5. I'm not clear yet which MODIS uses when they call theirs "HDF-EOS". But anyway. There are some ready-built binary libraries for both [https://support.hdfgroup.org/release4/obtain.html HDF4] and [https://support.hdfgroup.org/HDF5/release/obtain518.html HDF5] which look promising. Some linux builds, and also Windows builds in release mode, both 32-bit and 64-bit, built with Visual Studio 2013 and 2015. That's more helpful than most. | |||
Working out how to use them.... | |||
== Citation == | == Citation == | ||
Revision as of 13:41, 17 March 2017
About
MODIS data is collected by two satellites called Aqua (MOLA/MYD) and Terra (MOLT/MOD). Each satellite uses a 16 day period, and they are in antiphase, giving 8-day resolution. Some products are already combined into single datasets (MCD). A variety of fields are available. This document will describe the generic things about the dataset.
Getting Access
You need to sign up for a password, but after that, downloads are free. The download process is a bit tedious too, so scripting is the way. The source folders we've had reason to use are:
| https://e4ftl01.cr.usgs.gov/MOLA/MYD11A2.006/ | MODIS/Aqua Land Surface Temperature and Emissivity 8-Day L3 Global 1 km Grid SIN V006 |
| https://e4ftl01.cr.usgs.gov/MOLT/MOD11A2.006/ | MODIS/Terra Land Surface Temperature and Emissivity 8-Day L3 Global 1 km Grid SIN V006 |
| https://e4ftl01.cr.usgs.gov/MOLA/MYD13A2.006/ | MODIS/Aqua Vegetation Indices 16-Day L3 Global 1km Grid SIN V006 |
| https://e4ftl01.cr.usgs.gov/MOLT/MOD13A2.006/ | MODIS/Terra Vegetation Indices 16-Day L3 Global 1km Grid SIN V006 |
| https://e4ftl01.cr.usgs.gov/MOTA/MCD12Q1.051/ | MODIS Combined Land Cover Type Yearly L3 Global 500 m SIN Grid |
File Format
The file format is the HDF format. More details to follow, as I discover what exactly it is and how to interpet it.
Example Code
C
Two versions of HDF seem to be common: HDF4 and HDF5. I'm not clear yet which MODIS uses when they call theirs "HDF-EOS". But anyway. There are some ready-built binary libraries for both HDF4 and HDF5 which look promising. Some linux builds, and also Windows builds in release mode, both 32-bit and 64-bit, built with Visual Studio 2013 and 2015. That's more helpful than most.
Working out how to use them....
Citation
For the datasets we used above:-
Z. Wan, S. H., G.Hulley. (2015). MYD11A2 MODIS/Aqua Land Surface Temperature/Emissivity 8-Day L3 Global 1km SIN Grid V006. NASA EOSDIS Land Processes DAAC. https://doi.org/10.5067/MODIS/MYD11A2.006
Z. Wan, S. H., G.Hulley. (2015). MOD11A2 MODIS/Terra Land Surface Temperature/Emissivity 8-Day L3 Global 1km SIN Grid V006. NASA EOSDIS Land Processes DAAC. https://doi.org/10.5067/MODIS/MOD11A2.006
K. Didan. (2015). MYD13A2 MODIS/Aqua Vegetation Indices 16-Day L3 Global 1km SIN Grid V006. NASA EOSDIS Land Processes DAAC. https://doi.org/10.5067/MODIS/MYD13A2.006
K. Didan. (2015). MOD13A2 MODIS/Terra Vegetation Indices 16-Day L3 Global 1km SIN Grid V006. NASA EOSDIS Land Processes DAAC. https://doi.org/10.5067/MODIS/MOD13A2.006
(No specific citation for the MCD dataset)