ca_flooding_201902/modis_1dayfloodmap

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Service Description: Background: MODIS Flood 1 Day Observations is a collection of GeoTiffs representing 1D1OS WMP : 1 Day imagery, 1 Observations required, Terrain & Cloud Shadow Masking. NASA Goddard's Hydrology Laboratory is working to operationalize near real-time global flood mapping using available satellite data resources -- currently the twice daily overpass of the MODIS instrument, on the Terra and Aqua satellites. We are working to include additional data sources, such as Landsat and radar, to improve coverage and accuracy. This work builds on the long-time expertise and efforts of the Dartmouth Flood Observatory (DFO) to map floodwater extent in detail for active floods. The DFO website provides additional detail, additional products, and archives of historical flood maps. This NASA website provides links and information about the automated daily flood and surface water products produced at NASA Goddard. Note: The MODIS Flood 3 Day Image Service is the representing the MODIS Water Product (combines both MFW and MSW, raster only). There is no indication provided of where there is insufficient clear data in the given product to determine water extent. Thus, these products only indicate where water has been detected, but the absence of a water polygon cannot be interpreted to mean there was no water present in a given area; it may simply have been sufficiently cloudy over the composite period for the required number of water observations to be met (the Y in composite indicator XDYO). The MWP product (below) attempts to address this deficiency, and may eventually replace MFW and MSW. These vector products can also be extremely resource intensive to generate from the source raster; a partly cloudy scene over water, or a tile over mountains with terrain shadow issues, can have tens of thousands of polygons, if we were to convert to shapefile or KMZ. Thus, we typically skip vector product generation if the number of polygons is greater than 20000. Currently delivered only in geotiff raster format. We detect water using an algorithm developed by Bob Brakenridge of the Dartmouth Flood Observatory. This algorithm uses a ratio of MODIS Band 1 and Band 2, and a threshold on Band 7 to provisionally identify pixels as water. We then composite the water detections over the product window (2 days, typically). If a pixel is identified as water over several (2 or more) observations during the product window, it is then definitively marked as water, and output in the MSW, or "MODIS Surface Water" product. 2 (or more) observations are required because cloud shadow can appear quite spectrally similar to water. In cases where cloud shadow occurs in the same spot in 2 observations, the product may incorrectly flag such areas as water. A 3 observation requirement helps further, but also increases latency of the product. At the moment, we are using the 2 observation requirement as a balance between accuracy and timeliness. Finally, the detected water is compared to a reference water layer that shows "normal" water extent, and any pixels found outside the normal water extent are marked as flood, and output in the MFW ("MODIS Flood Water") products. The Image Service is published using a Raster Mosaic populated with “MWP” GeoTiffs collected from the NRT Global Flood Mapping Data Viewer site. Data Visualization: MODIS Flood layer is represented using Unique Values Ranging from 0-3. 0 : Insufficient data to make water determination (cloudy, missing images, swath gaps, or bad data values). 1 : No water detected. 2 : Water detected AND coinciding with reference water (e.g., not flood). 3 : Water detected, beyond reference water, so may be flood. Update Frequency: Daily Suggested Usage: Flood detection and showing areas of surface water inundation. Further Reference: Learn more about MODIS Flood Products Purpose/Summary: Flood Detection Map, MODIS Flood 1 Day (1D1OS), Updated Daily

Name: ca_flooding_201902/modis_1dayfloodmap_20190228

Description: Background: MODIS Flood 1 Day Observations is a collection of GeoTiffs representing 1D1OS WMP : 1 Day imagery, 1 Observations required, Terrain & Cloud Shadow Masking. NASA Goddard's Hydrology Laboratory is working to operationalize near real-time global flood mapping using available satellite data resources -- currently the twice daily overpass of the MODIS instrument, on the Terra and Aqua satellites. We are working to include additional data sources, such as Landsat and radar, to improve coverage and accuracy. This work builds on the long-time expertise and efforts of the Dartmouth Flood Observatory (DFO) to map floodwater extent in detail for active floods. The DFO website provides additional detail, additional products, and archives of historical flood maps. This NASA website provides links and information about the automated daily flood and surface water products produced at NASA Goddard. Note: The MODIS Flood 3 Day Image Service is the representing the MODIS Water Product (combines both MFW and MSW, raster only). There is no indication provided of where there is insufficient clear data in the given product to determine water extent. Thus, these products only indicate where water has been detected, but the absence of a water polygon cannot be interpreted to mean there was no water present in a given area; it may simply have been sufficiently cloudy over the composite period for the required number of water observations to be met (the Y in composite indicator XDYO). The MWP product (below) attempts to address this deficiency, and may eventually replace MFW and MSW. These vector products can also be extremely resource intensive to generate from the source raster; a partly cloudy scene over water, or a tile over mountains with terrain shadow issues, can have tens of thousands of polygons, if we were to convert to shapefile or KMZ. Thus, we typically skip vector product generation if the number of polygons is greater than 20000. Currently delivered only in geotiff raster format. We detect water using an algorithm developed by Bob Brakenridge of the Dartmouth Flood Observatory. This algorithm uses a ratio of MODIS Band 1 and Band 2, and a threshold on Band 7 to provisionally identify pixels as water. We then composite the water detections over the product window (2 days, typically). If a pixel is identified as water over several (2 or more) observations during the product window, it is then definitively marked as water, and output in the MSW, or "MODIS Surface Water" product. 2 (or more) observations are required because cloud shadow can appear quite spectrally similar to water. In cases where cloud shadow occurs in the same spot in 2 observations, the product may incorrectly flag such areas as water. A 3 observation requirement helps further, but also increases latency of the product. At the moment, we are using the 2 observation requirement as a balance between accuracy and timeliness. Finally, the detected water is compared to a reference water layer that shows "normal" water extent, and any pixels found outside the normal water extent are marked as flood, and output in the MFW ("MODIS Flood Water") products. The Image Service is published using a Raster Mosaic populated with “MWP” GeoTiffs collected from the NRT Global Flood Mapping Data Viewer site. Data Visualization: MODIS Flood layer is represented using Unique Values Ranging from 0-3. 0 : Insufficient data to make water determination (cloudy, missing images, swath gaps, or bad data values). 1 : No water detected. 2 : Water detected AND coinciding with reference water (e.g., not flood). 3 : Water detected, beyond reference water, so may be flood. Update Frequency: Daily Suggested Usage: Flood detection and showing areas of surface water inundation. Further Reference: Learn more about MODIS Flood Products Purpose/Summary: Flood Detection Map, MODIS Flood 1 Day (1D1OS), Updated Daily

Single Fused Map Cache: false

Extent:

Initial Extent:

Full Extent:

Pixel Size X: 0.0021968365553602814

Pixel Size Y: 0.0021968365553602814

Band Count: 1

Pixel Type: U8

RasterFunction Infos: {"rasterFunctionInfos": [ { "name": "MODIS Flood Symbology", "description": "MODIS Flood's function template for the DAG IOC.", "help": "" }, { "name": "None", "description": "", "help": "" } ]}

Mensuration Capabilities: Basic

Has Histograms: false

Has Colormap: false

Has Multi Dimensions : false

Rendering Rule:

Min Scale: 0

Max Scale: 0

Copyright Text: National Aeronautics and Space Administration (NASA), Goddard Space Flight Center's (GSFC) Hydrological Sciences Laboratory

Service Data Type: esriImageServiceDataTypeGeneric

Min Values: N/A

Max Values: N/A

Mean Values: N/A

Standard Deviation Values: N/A

Object ID Field:

Fields: None

Default Mosaic Method: Center

Allowed Mosaic Methods:

SortField:

SortValue: null

Mosaic Operator: First

Default Compression Quality: 75

Default Resampling Method: Nearest

Max Record Count: null

Max Image Height: 4100

Max Image Width: 15000

Max Download Image Count: null

Max Mosaic Image Count: null

Allow Raster Function: true

Allow Copy: true

Allow Analysis: true

Allow Compute TiePoints: false

Supports Statistics: false

Supports Advanced Queries: false

Use StandardizedQueries: true

Raster Type Infos:

Has Raster Attribute Table: false

Edit Fields Info: null

Ownership Based AccessControl For Rasters: null

Child Resources: Info Statistics Key Properties Legend Raster Function Infos

Supported Operations: Export Image Identify Measure Compute Histograms Compute Statistics Histograms Get Samples Compute Class Statistics Query Boundary Compute Pixel Location Compute Angles Validate Project

ca_flooding_201902/modis_1dayfloodmap_20190228 (ImageServer)