MODIS data for LTER sites produced at CREATE

The Center for Rapid Environmental Assessment and Terrain Evaluation (CREATE), has installed automated scripts into its processing system to extract MODIS data from its processing stream for regions encoumpassing sites of the Long Term Ecological Research Network (LTER)

The input for the products are DIRECT READOUT MODIS data acquired real-time by the CREATE acquisition and processing system.

The area currently extracted is a 128km by 128km region centered each LTER sites. Depending on the MODIS data product, the resolution varies from 250 meter for MODIS bands 1 and 2 and related products, 500 meters for MODIS bands 3-7 and related products and 1km resolution for other MODIS data.

The first step in the processing is to generate simple browse images as the data are aquired. The primary purpose of the browse images are simple to view various data products - as simple jpeg image files. Once a suitable data set is noted, the primary GEOTIFF data products can be access as input to standard GIS and image processing software such as ENVI, or Erdas/Imagine.


Access LTER Browse Images





Example browse image as MODIS bands 2,1,1=RGB , Niwot Ridge LTER scene, November 3, 2007, 18:01GMT

250m resolution, 128x128km


Input DATA file of Niwot Ridge LTER November 03, 2007 18:01GMT scene of Cloud-Screened Normalized Difference Vegetation data product as viewed as the raw browse image and after import into Erdas/Imagine and enhancement from low to high EVI as R,G,B and cloud mask as black.


Input DATA file of Niwot Ridge LTER scene of "snow_covered_land" viewed as raw "browse images" and after import into Erdas/Imagine and conversion to snow, clound and bare ground products. Note that the cloud mask in the previous NDVI data has not been incorporated into this data set.

Output "DATA" products:

The primary objective of the data acqusition for LTER sites is to generate raw DATA products. Rather than more complicated HDF products, all data are converted to standard GEOTIFF format data files. The GEOTIFF data are SIGNED 16-bit data, with a data value of -32,768 generally used as a "bad" data value, or the data value of a cloud mask, when present.

Version: 1
Key_Revision: 1.0
ModelTiepointTag (2,3):
0 0 0
-64000 64000 0
ModelPixelScaleTag (1,3):
250 250 0
GTModelTypeGeoKey (Short,1): ModelTypeProjected
GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
GTCitationGeoKey (Ascii,16): "TeraScan Export"
GeographicTypeGeoKey (Short,1): User-Defined
GeogCitationGeoKey (Ascii,16): "Spherical Earth"
GeogGeodeticDatumGeoKey (Short,1): User-Defined
GeogLinearUnitsGeoKey (Short,1): Linear_Meter
GeogAngularUnitsGeoKey (Short,1): Angular_Degree
GeogEllipsoidGeoKey (Short,1): User-Defined
GeogSemiMajorAxisGeoKey (Double,1): 6378137
GeogSemiMinorAxisGeoKey (Double,1): 6378137
ProjectedCSTypeGeoKey (Short,1): User-Defined
ProjectionGeoKey (Short,1): User-Defined
ProjCoordTransGeoKey (Short,1): CT_LambertAzimEqualArea
ProjLinearUnitsGeoKey (Short,1): Linear_Meter
ProjNatOriginLongGeoKey (Double,1): -105.37555
ProjNatOriginLatGeoKey (Double,1): 40.01
ProjFalseEastingGeoKey (Double,1): 0
ProjFalseNorthingGeoKey (Double,1): 0

Projection Method: CT_LambertAzimEqualArea
ProjCenterLatGeoKey: 40.010000 ( 40d 0'36.00"N)
ProjCenterLongGeoKey: -105.375550 (105d22'31.98"W)
ProjFalseEastingGeoKey: 0.000000 m
ProjFalseNorthingGeoKey: 0.000000 m
Projection Linear Units: 9001/metre (1.000000m)

Corner Coordinates:
Upper Left ( -64000.000, 64000.000)
Lower Left ( -64000.000, -64000.000)
Upper Right ( 64000.000, 64000.000)
Lower Right ( 64000.000, -64000.000)
Center ( 0.000, 0.000)

The image and data products generated for LTER sites are a work in progress, with changes being applied with input from LTER sites, changes in processing capabilities and overall evalutation of the quality of output data products from the raw Direct Readout Data.


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