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GIS, GNSS, & Remote Sensing
NREM 301, Spring 2012 Tomoaki Miura, Guest Lecturer
GIS Overlay for Analysis & Map Creation
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Comprehending Existing Information into a Geodatabase
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Predicting Future Land Use with GIS
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What Types of Data Are Available/Used?
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What Types of Data Are Available/Used? (cont.)
Single-layer raster Multi-layer raster
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Vector Representation
A physical entity is represented by a spatial object in a GIS. Here, physical boundaries of lakes are represented by lines. 8
Coordinates & Attributes
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A Typical GIS Data Structure
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Topology
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Topology (cont.)
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Digital Elevation Model (DEM)
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Emerge
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Orthophotoquads
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EarthData
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C-CAP
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GAP
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Erase
Union
Reclass
Reclass
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Suitability Assessment
Remote Sensing
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Band 1 (Blue: 0.4 – 0.5 μm)
Band 2 (Green: 0.5 – 0.6 μm)
Band 3 (Red: 0.6 – 0.7 μm)
Band 4 (NIR: 0.78 – 0.90 μm)
Band 5 (SWIR1: 1.55 – 1.75 μm)
Band 7 (SWIR2: 2.0 – 2.35 μm) 26
True Color Composite 27
False Color Composite (4,3,2) 28
False Color Composite (4,5,3) 29
Where Are We?
21.30oN / 157.81oW
21.30oN / 157.81oW
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UTM4N, NAD83 32
GNSS (Global Navigation Satellite System) - GPS (Global Positioning System) -
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The Satellite Segment of GPS 6 unique orbital planes w/
ascending nodes approx. 60 degrees apart.
Their orbit inclinations at 55 degrees to the equator.
4 GPS satellites in each of these orbital planes.
20,200 km altitudes.
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The Satellite Segment of GPS (cont.)
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In Aug. & Sep. 2005, 6 additional monitor stations of the NGA (National Geospatial-Intelligence Agency) were added to the grid. Now, every satellite can be seen by, at least 2 monitor stations.
In the near future, 5 more NGA stations will be added so that every satellite can be seen by, at least 3 stations.
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Positional Uncertainty - Sources of Range Error -
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GPS Error Budget Ionosphere.......................................5.0 meters Troposphere.....................................0.5 meters Ephemeris data................................2.5 meters Satellite clock drift............................1.5 meters Multipath..........................................0.6 meters Measurement noise.........................0.3 meters Selective availability..................30-100 meters
Total..............................................~ 10 meters
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Other Factors for Consideration: Positional Dilution of Precision (PDOP)
*15 degrees above the local horizontal plane 45
Other Factors for Consideration: Blocked (Attenuated) Signals
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Differential Correction
*Good correction found when the roving receiver is within 300 km (180 miles) of base station. 47
Wide Area Augmentation System (WAAS) The Federal Aviation
Administration (FFA) The Department of
Transportation (DOT) To meet the FAA’s navigation
requirements for precision flight approaches
25 ground reference stations
across USA The corrected differential
signals broadcast through a geostationary satellite
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WAAS Coverage
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Garmin GPS Control Panel
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Mapping- / Survey-grade GPS
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Summary of GPS Accuracy
150 m The original GPS system under the Selective Availability (SA) program
15 m Typical GPS positional accuracy without SA
4-6 m Typical differential GPS (DGPS) positional accuracy
3-5 m Typical WAAS positional accuracy
< 1 m “Mapping-grade” GPS units
~ cm “Survey-grade” GPS units 52
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