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

http://hawaii.gov/dbedt/gis/

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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