LP_DAAC_MYD

This document describes the LP DAAC MYD HDF-EOS2 and HDF4 files.

HDF-EOS2 Swath files

The swath files use dimension maps and users need to either find the corresponding geolocation HDF-EOS2 files or calculate the latitude/longitude based on dimension map parameters. The size of dimension varies in geolocation fields and data fields.
For example, in file MYD11_L2.A2007093.0735.005.2007101061952.hdf, the dimension size of geolocation is 406 (Coarse_swath_lines_5km) x 271 (Coarse_swath_pixels_5km), while the dimension size of data fields is 2030 (Along_swath_lines_1km) x 1354 (Cross_swath_pixels_1km)

The following table summarizes the information collected for the files:

File type	File size(avg.)	Geolocation Field	Datafield Dim. Range	CF-compliant information	Other special issues
HDF-EOS2 (Swath)	3MB	Lat/Lon = 2D	2D	Both geolocation field and datafields have ‘units’ and ‘long_name’ attributes.	Use dimension map

HDF-EOS2 grid files

The projection of them is GEO or SNSOID. The following table summarizes the information collected for the files:

File type	File size(avg.)	Number of grid	Has lat/lon	Projection	Datafield Dim. Range	CF-compliant information	Other special issues
HDF-EOS2 (Grid)	91KB -593MB	1 or 2	No	GEO, or SNSOID*	1D - 3D	Data fields have 'units' and 'long_name' attributes.	Some files contain following issues: Hybrid file

* Some software tools requires extra steps to retrieve latitude and longitude for SNSOID projection

HDF4 files

The following table summarizes the information collected for the HDF4 files:

File type	File size(avg.)	Datafield Dim. Range	CF-compliant attributes information	Other special issues
HDF4	284KB	1D, 2D	Geo fields and part data fields have both 'units' and 'long_name' attributes.	FP_latitude and FP_longitude, which are equivalent to latitude and longitude, has zero length in one dimension

To retrieve sample MYD files and read the detailed description, please click here.

Last modified: 06/02/2017