The Terra Moderate Resolution Imaging Spectroradiometer (MODIS) Land Water Mask (MOD44W) Version 6 data product provides a global map of surface water at 250 meter (m) spatial resolution. The data are available annually from 2000 to 2015. MOD44W Version 6 is derived using a decision tree classifier trained with MODIS data and validated with the Version 5 MOD44W data product. A series of masks are applied to address known issues caused by terrain shadow, burn scars, cloudiness, or ice cover in oceans. A primary improvement in Version 6 is the generation of time series data rather than a simple static representation of water, given that water bodies fluctuate in size and location over time due to both natural and anthropogenic causes. Provided in each MOD44W Version 6 Hierarchical Data Format 4 (HDF4) file are layers for land, water, no data, and an associated per pixel quality assurance (QA) layer that provides users with information on the determination of water.
|File Size||~500 KB|
|Temporal Extent||2000-01-01 to 2015-12-31|
|Geographic Dimensions||1200 km x 1200 km|
|Number of Science Dataset (SDS) Layers||2|
|Columns/Rows||4800 x 4800|
|Pixel Size||250 m|
|SDS Name||Description||Units||Data Type||Fill Value||No Data Value||Valid Range||Scale Factor|
|Water_mask||Land/Water Mask||N/A||8-bit unsigned integer||250||253||0 to 1||N/A|
|Water_mask_QA||Quality Assurance (QA)||N/A||8-bit unsigned integer||10||253||1 to 8||N/A|
|250||Outside of Projection|
|1||High confidence observation|
|2||Lower confidence water, but MOD44W V5 indicated water|
|3||Lower confidence land|
|5||Ocean mask, but no water observations recorded|
|6||Burned area (MCD64A1)|
|7||Urban or impervious surface|
|8||No water detected, but MOD44W V5 shows inland water|
|10||Fill (outside of projected area)|
Quality information is provided in the Water Mask QA layer. Additional product quality information is provided on page 5 of the User Guide and Algorithm Theoretical Basis Document (ATBD).
The mask area for pixels outside of the Sinusoidal Grid for tile h27v14 should be labeled as 250 (Outside of Projection) instead of 0 (Land) and the QA values should be 10 (Fill) instead of 3 (Lower confidence land) for years 2000 through 2015.
Additional known issues are described in the User Guide and ATBD.