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Modis MYD03 and MOD03 files contain Land/SeaMask (uint8 with valid_range=0,7) and WaterPresent (uint8 with valid_range=0,8). Though the attribute fields define the valid range, they do not define the semantics of the actual values.

  • What do the values actually mean?
  • Where is a good place to search for these sort of information?

1 Answer 1

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According to the collection 6 MOD03 documentation the values of the Land/Sea mask refer to.

  • 0: Shallow Ocean (Ocean <5k from coast OR <50m deep).
  • 1: Land (not anything else).
  • 2: Ocean Coastlines and Lake Shorelines.
  • 3: Shallow Inland Water (Inland Water < 5km from shore OR < 50m deep).
  • 4: Ephemeral (intermittent) Water.
  • 5: Deep Inland Water (Inland water > 5km from shoreline AND > 50m deep).
  • 6: Moderate or Continental Ocean (Ocean > 5km from coast AND > 50m deep AND < 500m deep).
  • 7: Deep Ocean (Ocean > 500m deep).

Water Present is defined as:

High resolution water mask  uint8   
The low resolution Land/Water mask is filled in by first
extracting a Land/Water mask value for the center of each 500m
pixel, from a source tabulated with 15 arc second resolution,
and then aggregating those values to 1km resolution, giving the
center two pixels doubled weight. This SDS indicates the total
weight of all high resolution water pixels (Land/Water mask
values 0 or 3-7) that were aggregated into the low resolution
Land/Water mask.

NASAs MODAPS website contains information about all MOdis DAta ProductS.

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  • Thanks, for the links. After clicking through these pages I still cannot find the definitions for WaterPresent.
    – georg
    Oct 5, 2015 at 15:25
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    See my edit. Both information are from the linked mod03.geolocation.fs
    – Kersten
    Oct 5, 2015 at 18:18
  • without going into details of that definition, this basically means: 8=water and nothing else and 0=land and nothing else the rest 1,2,...,7=mixture of water and land ?
    – georg
    Oct 6, 2015 at 9:17
  • I understand it that way as well. 0 means no-water, 3-7 low to high water coverage, 8 complete water coverage. 1-2 are not possible due to the doubled weight of the center two pixels.
    – Kersten
    Oct 6, 2015 at 9:40
  • I agree, it reads like this. But I have a file here (MYD03.A2008001.0040.006.2012201150018.hdf) containing 1 and 2 ... anyway, thx for your help
    – georg
    Oct 6, 2015 at 9:46

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