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Intro to Geographic Information Systems
Home » People » Judd Curran » GIS » Class Website Content

Class Website Content


Welcome to Geography 104
In this section of our website, you will find helpful information
and links related to the topics being discussed in class each week.
The content of this section will be updated weekly.

Required Text:  Getting to Know ArcGIS Desktop, 3rd edition., updated for ArcGIS 10.0
Help With Installation of ArcGIS Software
(Student Trial Version) on Your Personal Computer
and additional assistance can be found at....
Additional Help with installation of ArcGIS 10 software (Trial Version)
To install ArcGIS 10 on your computer, your operating system (Windows 7,8, Vista, etc) must be updated with the latest updates available.
1st Day PowerPoint Presentation:
Systems, Science, and Applications
Although beginning students may not know much about GIS at the start of the semester, a successful student will be able to implement a GIS project from start to finish by the end of the semester.  Here are a few examples of projects that students have created in this class in past semesters:

Student Project Example #1

Student Project Example #2
GIS has been defined in several ways.....
1.  "  A powerful set of tools for storing and retrieving at will, transforming and displaying spatial data from the real world for a particular set of purposes."
Peter Burrough
2.  "Automated systems for the capture, storage,
retrieval, analysis, and display of spatial data."
Keith Clarke
3.  "An information system that is designed to work with data referenced by spatial or geographic coordinates.  In other words, a GIS is both a database system with specific capabilities for spatially-referenced data, as well as a set of operations for working with the data."  Jack Estes
4.  "A GIS is a special case of IS where the database consists of observations on spatially-distributed features, activities, or events which are definable in space as points, lines, and areas to retrieve data for ad hoc queries and analyses."
Ken Duecker
Six Parts of a GIS, from Geographic Information Systems and Science
From:  Geographic Information Systems and Science, 2nd ed.
Paul Longley, Michael Goodchild, David Maguire, and David Rhind
The Basics of GIS
Kenneth E. Foote and Margaret Lynch,
The Geographer's Craft Project,
Department of Geography,
The University of Colorado at Boulder

The three elements of GI Science

GI Science

Individual:  Research dominated by cognitive science (the process of learning and knowing).  Understanding spatial concepts,
learning and reasoning about geographic data,
and computer interaction.

Computer:  Research about representation, adoption of new technologies, computation, and visualization.

Society:  Research about issues of impacts and societal context. 

Problem-solving applications
A. Objective or Goal Driven
For example, problem-solving to maximize or minimize costs or distances
B.  Tangible vs. Intangible
For example, problem-solving that examines physical things that are
directly measureable (tangible) like the quantity of water in a stream versus
problem-solving that examines things that are not directly measurable such as assessing the quality of life or significance of environmental impacts (intangible).
C.  Multiple Objectives
For example, problem-solving that determines both the cost and
the environmental impacts.  This is often referred to as multi-criteria
decision making.

Salton Sea
Modeling the Environment of the Salton Sea with GIS
GIS and related Geospatial Technologies are part of the
High Growth Job Training Initiative
The High Growth Job Training Initiative is a strategic effort to prepare
workers to take advantage of new and increasing job opportunities in high
growth, high demand and economically vital sectors of the American economy.
Fields like health care, information technology, and advanced manufacturing have jobs
and solid career paths left untaken due to a lack of people qualified to fill them."
GIS - A Top High-Growth Industry
DOLETA - US Dept. of Labor (Employment and Training Admin.)
The Fourth R?
Rethinking GIS Education

Michael F. Goodchild

Week #2

Note:  If you are looking for the content that was
previously in this section (from last week), it has been
moved to the archived page.  You can access the archive
using the link in the column to the left titled,
"Class Website Content".
Representing Geography
This week, we will take a look at how spatial information
is transformed and represented.  Topics of discussion will
include datums, coordinate systems, and raster vs. vector
data representation.
Coordinate Systems
Cartesian Coordinate System

GIS outline
 UTM Zone 14
UTM 14 Det
Geographic Grid (Latitude and Longitude)
Spherical Grid System
Lat Long Globe
Data Types
Raster vs. Vector
"Raster is vaster, Vector is more correcter"
Illustration of a Line in Both Raster and Vector Format
Potential errors when exchanging data between raster and vector format
Readings in Longley Text
Chapter 3:  Representing Geography
Week 2 Lecture Reference Material


Projections and Scale
The Earth's image must be projected onto flat surfaces
like computer screens and paper maps. These flat representations
of the Earth are called “map projections.”

There are many types of map projections. No map projection
is perfect. Any map projection will have some error in representing
the Earth, but the inaccuracies can be reduced by choosing
the appropriate map projections for specific needs.

Projecting reality from 3-dimensions
to 2-dimensions.
Illustration of casting a shadow of a graticule onto a piece a paper
From ArcGIS Help
Different types of Projections
Website of Projection Examples
Projection Table
Projections Defined
Map Projections Overview
The Mercator projection shows courses of constant bearing as straight lines. While common, scholars advise against using it for reference maps of the world because it drastically inflates the high latitudes.
This projection shows all distances and directions correctly from a single point.
The Robinson projection is an example of
a pseudocylindrical, or orthophanic, projection
Albers Projection


The Magellan-Elcano Circumnavigation Route.  Shown in the Raisz Armadillo Projection.  Looks three-dimensional and equator is tilted upward.



The magellan-Elcano Circumnavigation Route.  Shown in the Canters Minimum-Error Projection.  Shape distortion is reduced.


The Voyager Flight.  Shown in the Robinson Projection.  The shapes of areas are well-preserved.  Path is shown with minimal distortion



The Voyager Flight.  Shown in the Oblique Lambert Azimuthal Equal-Area Projection.  Emphasizes circular nature of flight.  Flight path is not interrupted.


Sputnik I.  Shown in the Miller Cylindrical Projection.  Good for highlighting cyclical nature of orbiting path.  But, increasingly distorts area poleward.


Sputnik I.  Shown in the Snyder Cylindrical Satellite-Tracking Projection.  Depicts satellite path as a set of straight lines.  But, distorts area and shape poleward.

© 1997, American Congress on Surveying and Mapping

Content from:
The Cartography and Geographic Information Society

Understanding the ratio between map and Earth. Displaying map features at pre-determined scales.  Different types of scale.

From:  Phil Hurvitz, Univ. of Washington

The essential problem of scale in a GIS is that all features are stored with precise coordinates (the computer stores numeric values), regardless of the precision of the original source data. Data which came from any mixture of scales can be displayed and analyzed in the same GIS project. The output of mixing data of differing scales can lead to erroneous or inaccurate conclusions.

Consider these two coordinates:

(125.875, 500.379)
(126.000, 500.000)

Both coordinates are stored with the same precision (3 decimal places). If we ignore the 3 decimal places of precision, the 2 coordinates are identical, but if we use the full precision of the data, the coordinates are different. Depending on the scale at which you view these points, they will either look like a single point or they will look like 2 separate points. As you zoom in closer, the relative distance between the points will increase.

Using data from many different scales introduces these types of problems. The adage "A chain is only as strong as its weakest link" applies here; the accuracy and precision of measurements, maps, and models from a GIS are only as good as the least accurate and precise data source.

Copyright © Phil Hurvitz, 1998-2004

USGS Map Scale Fact Sheet
In-lab Exercise


Geovisualization is the process of developing maps
in GIS that are constructed and used as "windows into the database"
to support queries, analysis, and editing of information.
Tables and Attribute Data
Querying Data In Tables
Four Ways to get information about features:
Ø     Identify Features: Click on a feature in the map with the Identify tool to display attribute information. [fastest way to get info about a single feature]
Ø     Selecting Features Interactively:  Click on features in the map to highlight them, then look at their records in the attribute table. [best for comparing several features]
Ø     Selecting Features by Attributes:  Write a Query [SQL] that automatically selects features that meet a certain criteria.
Ø     Finding Features:  Provide ArcMap with a piece of information (such as a name) to see which feature is belongs to.
Modifying Existing Tables
Joining, Relating, Linking, Hyperlinking
Creating, and Importing Tables in GIS
Joining Tables
Join Example:  From ArcGIS Desktop Help (ESRI, Inc.)

Table From ArcGIS Desktop Help, (ESRI, Inc.)
Relating Tables
Related Tables
Structured Query Language [SQL] Fundamentals
In-Lab Tutorial
Ch's 8-9
Freeway Data
Readings in Longley Text
Chapter 4: The Nature of Geographic Data


Good Student Answer to Question #1 of Quiz #1:
Data Acquisition

Data Sources
Spatial/Temporal Characteristics of Remote Sensing Systems
Spatial/Temporal Resolution Characteristics
"Spatial and temporal characteristics of commonly used remote sensing systems and
their sensors"
From:  Geographic Information Systems and Science, 2nd ed.
Paul Longley, Michael Goodchild, David Maguire, and David Rhind.  Originally From:
Jenson, J.R. and Cowen, D.C.  1999 'Remote Sensing of urban/suburban infrastructure
and socioeconomic attributes' PERS, 65, 611-622.
Views From Different Satellites
Interactive Resolution Comparison
Contact the instructor if you have difficulty viewing this image
Polar Orbiting Satellites vs Geostationary Satellites
International Geostationary Systems
Polar Orbiting Satellites complete 14 orbits per day, thus
covering the entire earth twice in a 24-hour period.  They pick
up the high-latitudes that are not covered by the Geostationary
satellites.  Their track runs nearly North to South passing close
to both poles.  They make back and forth swaths.
Pixels in an image.

SPOT Satellite
Bands 4-7 (.5-1.1ƛ)
What spectral bands to I use for my study?
Contact the instructor if you have difficulty viewing this image
A time lapse of a small portion of the geostationary orbit taken from atop Kitt Peak in Arizona from 0230Z to 11Z on March 19, 2007. The lines represent star trails, while the bright dots mark the positions of geostationary satellites. Courtesy of Dave Dooling, National Solar Observatory.  This image only accounts for 9% of all geostationary satellites orbiting Earth.

Federal Geographic Data Committee Standards [FGDC]
Error, Accuracy, and Precision
Data Transfer
From:  Geographic Information Systems and Science, 2nd ed.
Paul Longley, Michael Goodchild, David Maguire, and David Rhind.
Managing Error
OGC:  The Open Geospatial Consortium
Cal-Fire website link broken as of Spring 2014
Use the following temporary link to access
the Fire Hazard Severity Zones
Readings in Longley Text
Chapter 9:  GIS Data Collection
Chapter 6:  Uncertainty



Data Acquisition Continued
Global Positioning Systems (GPS)
GPS Satellite
GPS Satellite
Photo from U.S. Army
About GPS
How Does GPS Work?
Locating via Trilateration
Free Software for Downloading
and Working with Waypoints

The Space Component
GPS Space

Image Source:  FAA

24 Satellites

From Website

The Space component consists of:

The space segment includes the satellites and the Delta rockets that launch the satellites from Cape Canaveral, in Florida. GPS satellites fly in circular orbits at an altitude of 10,900 nautical miles (20,200 km) and with a period of 12 hours. The orbits are tilted to the earth's equator by 55 degrees to ensure coverage of polar regions. Powered by solar cells, the satellites continuously orient themselves to point their solar panels toward the sun and their antenna toward the earth. Each of the 24 satellites, positioned in 6 orbital planes, circles the earth twice a day.

The satellites are composed of:

Solar Panels. Each satellite is equipped with solar array panels. These panels capture energy from the sun, which provides power for the satellite throughout its life.

External components such as antennas. The exterior of the GPS satellite has a variety of antennas. The signals generated by the radio transmitter are sent to GPS receivers via the L-band antennas. Another component is the radio transmitter, which generates the signal. Each of the 24 satellites transmits it's own unique code in the signal.

Internal components such as atomic clocks and radio transmitters. Each satellite contains four atomic clocks. These clocks are accurate to at least a billionth of a second or a nanosecond. An atomic clock inaccuracy of 1/100th of a second would translate into a measurement (or ranging) error of 1,860 miles to the GPS receiver.


The Control Component
GPS Control
Image Source:  FAA

The Control Segment of GPS consists of:

Master Control Station: The master control station, located at Falcon Air Force Base in Colorado Springs, Colorado, is responsible for overall management of the remote monitoring and transmission sites. GPS ephemeris being a tabulation of computed positions, velocities and derived right ascension and declination of GPS satellites at specific times, replace "position" with "ephemeris" because the Master Control Station computes not only position but also velocity, right ascension and declination parameters for eventual upload to GPS satellites.

Monitor Stations : Six monitor stations are located at Falcon Air Force Base in Colorado, Cape Canaveral, Florida, Hawaii, Ascension Island in the Atlantic Ocean, Diego Garcia Atoll in the Indian Ocean, and Kwajalein Island in the South Pacific Ocean. Each of the monitor stations checks the exact altitude, position, speed, and overall health of the orbiting satellites. The control segment uses measurements collected by the monitor stations to predict the behavior of each satellite's orbit and clock. The prediction data is up-linked, or transmitted, to the satellites for transmission back to the users. The control segment also ensures that the GPS satellite orbits and clocks remain within acceptable limits. A station can track up to 11 satellites at a time. This "check-up" is performed twice a day, by each station, as the satellites complete their journeys around the earth. Noted variations, such as those caused by the gravity of the moon, sun and the pressure of solar radiation, are passed along to the master control station.

Ground Antennas: Ground antennas monitor and track the satellites from horizon to horizon. They also transmit correction information to individual satellites.

The User Component

The user component consists of:

The user segment includes the equipment of the military personnel and civilians who receive GPS signals. Military GPS user equipment has been integrated into fighters, bombers, tankers, helicopters, ships, submarines, tanks, jeeps, and soldiers' equipment. In addition to basic navigation activities, military applications of GPS include target designation, close air support, "smart" weapons, and rendezvous.

With more than 500,000 GPS receivers, the civilian community has its own large and diverse user segment. Surveyors use GPS to save time over standard survey methods. GPS is used by aircraft and ships for enroute navigation and for airport or harbor approaches. GPS tracking systems are used to route and monitor delivery vans and emergency vehicles. In a method called precision farming, GPS is used to monitor and control the application of agricultural fertilizer and pesticides. GPS is available as an in-car navigation aid and is used by hikers and hunters. GPS is also used on the Space Shuttle. Because the GPS user does not need to communicate with the satellite, GPS can serve an unlimited number of users.

The aviation community is using GPS extensively. Aviation navigators, equipped with GPS receivers, use satellites as precise reference points to trilaterate the aircraft's position anywhere on or near the earth. GPS is already providing benefits to aviation users, but relative to its potential, these benefits are just the beginning. The foreseen contributions of GPS to aviation promise to be revolutionary. With air travel nearly doubled in the 21st Century, GPS can provide a cornerstone of the future air traffic management (ATM) system that will maintain high levels of safety, while reducing delays and increasing airway capacity. To promote this future ATM system, the FAA's objective is to establish and maintain a satellite-based navigation capability for all phases of flight.

NPS: GPS for GIS Workflow
GPS Overview
About WAAS
WAAS Near-Real-Time Coverage Map
Probation Officers Keep Tabs With GPS
GPS to GIS Tutorial
Readings in Longley Text
Chapter 5:  Georeferencing
Last Updated: 12/31/2014
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