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NRT Global MODIS Flood Mapping

ArcGIS Online Map and Image Service for flood product

ArcGIS Online Map and Image Service for flood product

Flood Map Users,

We have begun publishing our 2 and 3 day products as time-enabled ArcGIS Image Services. We are working on a front end interface for these services for our website, but this is not yet complete. In the meantime, a simple ArcGIS Online map is available here:

http://bit.ly/1xfGqCf

Note that the server supporting the map is relatively slow; it will typically take several seconds to redraw after a date change, for example. We are working on hardware upgrades to solve this, and hope to have them in place by the time the custom web interface is available in a few months.

Also note that the supporting Image Service will only draw 12 10x10 degree tiles at once, to avoid overloading the server. Thus, the initial global view of the map in ArcGIS Online will only show a scattering of drawn tiles. Please zoom in to your area of interest. We're working on global reduced-resolution image service that will draw globally, and highlight areas of potential flooding concern.

Also, there are some limitations inherent to the current version of ArcGIS Online that affect the usability of this map:

Legend: The displayed legend is not useful. But the interpretation is simple:
Red = flood water
Blue = non-flood water
Gray = cloud, or insufficient data to determine.
Time-slider: the time-slider does not automatically update to the current time-extent of the source Image Service. Thus, if you are interested in the most recent data, you will need to edit the time-slider properties:

  1. Click the Configure button to the right of the time-slider. 2.
  2. Click “Show advanced options”
  3. Set the Start Time and End Time to the period you are interested in.
  4. Set the Time Display to 1 Day interval.

Clicking on the map will confirm the date of the data displayed at that point.

Also, the time-slider becomes inconvenient to use if large time spans are configured, so its best to limit to the partciular period (a few weeks or month) of interest. The mosaic datasets behind the image services are populated back to May 2014, although some dates are missing.

More details are available by clicking the "More Details" link in the About tab, in the ArcGIS Online map.

If you would like to access the Image services directly, please let us know and we will provide additional information on how to do so; this can be done from within ArcMap, for example, or from your own session in ArcGIS Online.

As always, any feedback is greatly appreciated.

Best,

Dan





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