Using Freely Available. Remote Sensing to Create a More Powerful GIS

Transcription

1 Using Freely Available Government Data and Remote Sensing to Create a More Powerful GIS All rights reserved. ENVI, E3De, IAS, and IDL are trademarks of Exelis, Inc. All other marks are the property of their respective owners. 2012, Exelis Visual Information Solutions, Inc

2 Using Freely Available Government Data and Remote Sensing to Create a More Powerful GIS Topics for Today s Web Seminar > How to access this data and what the pros and cons are of using these different types of data > You ll learn how to use ENVI software to explore free government data, such as NAIP and Landsat satellite imagery > How this data can be used to help with various analyses, such as: > Performing land cover classifications for agricultural analysis > Identifying impervious surfaces to locate water runoff zones > Conducting image change detections to see what has changed over time > Analyzing a fire burn region to assess burn severity > Using your image analysis results and generate map products with ArcGIS

3 Freely Available Government Data Sources ASTER Advanced SpaceborneThermal Emission and Reflection Radiometer Multispectral, thermal, infrared data of high spatial resolution Instrument VNIR SWIR TIR Bands Spatial Resolution 15m 30m 90m Access data: The USGS GloVis tool: Image courtesy of NASA/GSFC/METI/Japan Space Systems, and U.S./Japan ASTER Science Team

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5 Freely Available Government Data Sources MODIS Moderate Resolution Imaging Spectroradiometer Spatial Resolution: 250 m 1000m MODIS views the entire Earth's surface every 1 to 2 days in 36 spectral bands Aids our understanding of global dynamics and processes occurring on the land, in the oceans, and in the lower atmosphere Access Data: MODIS Level 1 and atmosphere products: Land Products: Snow and sea ice cover: Image courtesy of Jeff Schmaltz MODIS Land Rapid Response Team, NASA GSFC

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14 Freely Available Government Data Sources ALI and Hyperion From Earth Observing-1 (EO-1) satellite (Advanced Land Imager) Spatial resolution of 30 meters for the multispectral bands and 10 meters for the panchromatic band Because EO-1 is a tasking satellite, it collects data only when requested. It does not provide continuous coverage of the Earth, and, therefore, may not have coverage data for your area of interest. To obtain imagery of an area not available in the archive (or to schedule a date for data acquisition) you can submit a Data Acquisition Request All Advanced Land Imager (ALI) and Hyperion data products are available for search and download through Earth Explorer or GloVis. ALI sampleimage (Mt Fuji, Japan) (left); Hyperion sample image (Mt Fuji, Japan) (right). Images courtesy of USGS

15 Freely Available Government Data Sources Landsat Spatial Resolution 30 meters LANDSAT-5 was equipped with a multispectral scanner (MSS) and thematic mapper(tm). MSS is an optical sensor designed to observe solar radiation, which is reflected from the Earth's surface in four different spectral bands, using a combination of the optical system and the sensor. TM is a more advanced version of the observation equipment used in the MSS, which observes the Earth's surface in seven spectral bands that range from visible to thermal infrared regions. Data Access: All Landsat data is in the USGS archive: A Landsat 5 image of Charleston, South Carolina acquired on November 14, Image courtesy of NASA.

16 Freely Available Government Data Sources NAIP National Agriculture Imagery Program Acquires aerial imagery during the agricultural growing seasons in the continental U.S. USDA's Farm Service Agency (FSA) through the Aerial Photography Field Office One-meter ground sample distance, default spectral resolution is natural color (Red, Green and Blue, or RGB) Starting in 2007, some states have been delivered RGB and Near Infrared Data access: CCMs are available for free download through the USDA Geospatial Data Gateway, NAIP imagery courtesy of FSA and USDA.

17 Advantages and Disadvantages ASTER > Is a great and comprehensive source of data with spectral and spatial resolutions > Can be used for local and landscape level analyses > However, it has more sporadic and spotty coverage and availability > ASTER SWIR data acquired since April 2008 are not useable, and show saturation of values and severe striping. > SWIR detectors are no longer functioning due to anomalously high SWIR detector temperatures: MODIS > Due to its spatial resolution, can give good continental scale trends -global land cover, weather trends, sea surface, salinity > Due to its spatial resolution, has very little amount for local data > Local applications (change detection, land cover analysis) are not appropriate with MODIS data

18 Advantages and Disadvantages ALI and Hyperion > Is a great and comprehensive source of data with spectral and spatial resolutions > Can be used for local and landscape level analyses, identification of materials, land cover, change detections > However, it has more sporadic and spotty coverage and availability > EO-1 is a tasking satellite, it collects data only when requested. It does not provide continuous coverage of the Earth, and, may not have coverage data for your area of interest. NAIP > Often 3 band data, more collected now with 4 bands (near infrared) > Can have good historical data for land cover changes, change detection, annual crop analysis > Not ideal for disaster or emergency analysis, since it s collected once a year.

19 Advantages and Disadvantages Landsat > One of the most thorough archives for data, consistent coverage for decades > Good spectral and spatial resolutions: you cannot see individual houses on a Landsat image, but you can see larger objects such as highways. This is an important spatial resolution because it is coarse enough for global coverage, yet detailed enough to characterize human-scale processes such as urban growth changes > Can use it to analyze longer term trends like net primary productivity and carbon sequestration > However, there has been a hardware failure for LANDSAT 7 images: on May 31, 2003, the Scan Line Corrector (SLC), which compensates for the forward motion of Landsat 7, failed

20 Land Cover Classifications for Agricultural Analysis Use NAIP imagery and the Classification Workflow in ENVI to create a Land Cover Map

21 Identifying Impervious Surfaces to Locate Water Runoff Zones NAIP Imagery Feature Extraction In addition to building a vegetation base map and change map to monitor future changes to vegetation health, we can identify all impervious surfaces in a region.

22 Conducting Image Change Detections 2000 Landsat Image 2006 Landsat Image ENVI Analysis Use the change detection workflow to analyze Landsat imagery from multiple dates to detect changes over time.

23 Analyzing a Fire Burn Region to Assess Burn Severity

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26 Conclusions Imagery As An Addition to your GIS > Get information rapidly in time critical situations > Get information in remote areas > Update geodatabases with more current information > Track changes over time > Identify and extract features of interest in an automated fashion > Image analysis increasingly easy to use with workflow processing

27 All rights reserved. ENVI, E3De, IAS, and IDL are trademarks of Exelis, Inc. All other marks are the property of their respective owners. 2012, Exelis Visual Information Solutions, Inc