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FEMA/Flood_Detection_Map (MapServer)

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Service Description: Layer names and descriptions are as follows: Coverage •All footprints merged and summed together to indicate coverage throughout the event. The pixel value indicates the number of times the pixel was sampled by a SAR- or MS- sensor acquisition used in the analysis. •Filename: EVENT_Coverage.tif Flood Extents Combined •All flood extents merged and summed together to indicate the number of times a pixel was identified as flooded throughout the event. The pixel value indicates the number of times the pixel was identified as “flooded” in a SAR- or MS- based flood extent. •Filename: EVENT_FloodExtentsCombined.tif Flood Detection % •All flood extents merged and summed together, divided by coverage, to indicate water detection percentage throughout the event. The pixel value ranges from 0% – 100% and equates to the number of times the pixel was identified as “flooded” in a SAR- or MS- based flood extent, divided by the number of times the pixel was sampled. •Flood Detection % = # times the pixel was identified as flooded / # times the pixel was sampled •Filename: EVENT_FloodDetection.tif Other important information: •The flood extents were derived from SAR and Multispectral imagery acquired over the course of 11 days for Harvey (Aug 26th – September 5th), 8 days for Irma (Sept 10th – September 17th ), and 4 days for Maria (September 20th - September 23rd). •Flood extents were provided by NASA MSFC SPoRT, ARIA NASA JPL/Caltech, MDA and Copernicus EMS using a wide range of sensors and sensor types, as well as different methodologies. •All flood extents were resampled to 30m spatial resolution. •In the Flood Detection % Raster, some pixels that were identified as “flooded” but only imaged once (ex. 1/1=100%) will have an equal detection % as pixels that were imaged several times and identified “flooded” each time (ex. 5/5=100%). It is best to view both the Coverage and the Flood Detection layers together to better understand how coverage affects the detection percentage. •Some smooth surfaces (such as roads/airports) have similar backscatter signature to water and may be falsely detected as “flooded”. Water detection in urban areas is limited due to spatial resolution and other building-related effects on radar signal. FEMA would also like to give credit to the following who provided source data, data processing services, and derived products used for this map service: •USGS HDDS •Copernicus EMS •Copernicus Sentinel data (2017) processed by ESA •SPoRT NASA MSFC •ARIA NASA JPL/Caltech •NGA for the Northernview Agreement (provides access to MDA Systems, Ltd.) •University of Alaska Fairbanks

Map Name: Layers

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Copyright Text: NASA MSFC SPoRT, ARIA NASA JPL/Caltech, MDA, Copernicus EMS

Spatial Reference: 102100  (3857)


Single Fused Map Cache: false

Initial Extent: Full Extent: Units: esriMeters

Supported Image Format Types: PNG32,PNG24,PNG,JPG,DIB,TIFF,EMF,PS,PDF,GIF,SVG,SVGZ,BMP

Document Info: Supports Dynamic Layers: true

MaxRecordCount: 1000

MaxImageHeight: 4096

MaxImageWidth: 4096

Supported Query Formats: JSON, AMF, geoJSON

Min Scale: 0

Max Scale: 0

Supports Datum Transformation: true



Child Resources:   Info   Dynamic Layer

Supported Operations:   Export Map   Identify   QueryDomains   Find   Return Updates