Introduction to Geographic Information Systems GIS

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Introduction to Geographic Information Systems
(GIS)
Note this presentation includes material from
Dr. Dionne Law, Dr. Marc Serre, and others.
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Organization of presentation

• Basics of GIS
• GIS data at the New Jersey Department of
  Environmental Protection

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Basics of GIS
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Geographic Information Systems (GIS)

• GIS facilitates visualization and analysis of
  spatial data
• Spatial data are stored in map layers

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Coordinate Systems

• Spatial data are referenced to locations on the
  earths surface using coordinate systems
• Ensure all map layers share a common coordinate
  system
• Recognized global coordinate systems consist of
• A Spheriod a mathematical description of the
  earths shape
• A Map Projection a mathematical conversion from
  spherical to planar coordinates

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Map Projection
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Map Projection
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Scale

• Tells how map distance relates to real world
  distance
• Map Scale ratio of map distance to actual
  ground distance
• 110,000 (1 map cm 10,000 real cm)
• Small scale (1100) vs. large scale (110)
• Scale Bar graphic display of map scale

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Resolution

• The accuracy with which a given map scale can
  depict the location and shape of map features
• Larger the map scale, the higher the resolution
• As map scale decreases, resolution diminishes and
  feature boundaries are smoothed, simplified, or
  not shown at all.
• Rule of thumb error 2 of map scale
• Resolution plays a large role in GIS, especially
  in raster-based modeling

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Raster-based GIS

• Data stored in a regularized grid of cells
  covering an area
• Grid cells called picture elements or pixels
• Nodes, Arcs, Areas

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Vector-based GIS

• Image and data stored separately
• Data attribute table
• Image points, lines, polygons

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Summary

• GIS facilitates visualization and analysis of
  spatial data
• Spatial data are stored in map layers
• Most GIS programs are raster- or vector- based
• Raster - data and image stored together in
  regularized grid made of pixels
• Vector - data and image stored separately
  points, lines and polygons

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GIS data at the New Jersey Department of
Environmental Protection
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New Jersey Department of Environmental Protection

• NJDEP
• http//www.nj.gov/dep/
• NJDEP - GIS
• http//www.nj.gov/dep/gis/
• NJDEP - Water Monitoring Standards
• http//www.state.nj.us/dep/wmm/
• NJDEP - Water Monitoring Standards Bureau of
  freshwater biological monitoring
• http//www.state.nj.us/dep/wmm/bfbm/

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NJDEP - GIS

• The NJDEP GIS Department (http//www.nj.gov/dep/
  gis/)
• provides GIS files for state administrative
  areas, hydrology, geology, land use, etc., such
  as
• Counties
• Digital Elevation Grid
• Hydrography
• Watersheds
• Water Quality Monitoring Stations

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NJDEP - Water Monitoring Standards

• The NJDEP Office of Water Monitoring Standards
• (http//www.state.nj.us/dep/wmm/)
• oversees the Bureau of Fresh Water and Biological
  Monitoring .
• This bureau is in charge of monitoring the
  ambient conditions of the state's fresh and
  ground water resources. This monitoring includes
  
• regular sampling through a statewide network
  consisting of 115 surface water monitoring
  stations,
• 820 benthic macroinvertebrate biological stream
  monitoring stations,
• 100 fish assemblage biological stream monitoring
  stations, and
• 150 ground water stations.

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The Raritan Basin in New Jersey
54 Monitoring Stations Across 3 Watershed
Management Areas
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Water quality data for the Raritan river basin

• Monitoring Station Data was gathered for 3
  Watershed Management Areas (WMA)
• N/S Branch Raritan (8)
• Lower Raritan (9)
• Millstone (10)
• Dataset was obtained from two sources
• NJ DEP/USGS Water Quality Network1
• EPA STORET Database2
• Dataset contains 6 water quality parameters
• Discharge, Dissolved Oxygen, Ammonia,
  NitrateNitrite, Phosphate, Temperature
• Additional Parameters can be added as needed
• Measurements were taken approximately 4
  times/year from 1990-2002
• Values were log-transformed depending on
  distribution

1http//waterdata.usgs.gov/nj/nwis/qw
2http//www.epa.gov/STORET
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Phosphate data (mg/L) over the Raritan
The movie of the data illustrate its space/time
variability
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Challenges

• Sparse network of monitoring sites
• Monitoring data may have varying measurement
  errors
• High variability of the data over space and time
• The relevant spatial distance metric is a
  combination across land and along river
  metric
• Limited resources prevents use of deterministic
  water quality models, but a stochastic version
  may provide useful knowledge

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Conclusion

• In the State of New Jersey, GIS provides a set of
  basic functions allowing to query and extract
  monitoring data with health concerns. The arcGIS
  software will provide the necessary basic
  functions of GIS.
• The monitoring data varies over space and time,
  therefore we need advanced functions of Temporal
  GIS to map their distribution at unsampled
  locations. The BMElib software of space/time
  Geostatistics will provide the necessary advanced
  functions of Temporal GIS

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ESRI arcGIS at UNC

• UNC GIS software includes ESRI arcGIS version
  9.0, 9.1, 9.2
• Technical Support http//www.unc.edu/atn/gis
• research_at_unc.edu (919) 962-HELP
• Data Sources http//gis.unc.edu/
• Amanda C. Henley, GIS Librarian
  amanda.henley_at_unc.edu [phone]