Transcript GIS for Teachers

Introduction to GIS
Harrisburg, Pennsylvania
June 20, 2001
Ryan Baxter - Chris Pfeiffer
Pennsylvania Spatial Data Access
www.pasda.psu.edu
GIS v. GPS
• GIS
– Geographic Information System
– Computer Mapping and Analysis Tool
• GPS
– Global Positioning System
– Handheld device that uses satellites to
determine your location
Definition of GIS
Geographic Information System
GIS is a System of computer software, hardware
and data, and personnel to help manipulate,
analyze and present information that is tied to a
spatial location –
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spatial location – usually a geographic location
information – visualization and analysis of data
system – linking software, hardware, data
personnel – a user who utilizes the power of GIS
What is a GIS…
• Maps in a computer
• Layers…
– “Alike” features are
combined in their
own layer (e.g.,
roads or parks)
– Layers can be
overlaid like
transparencies
– Map sandwich
Illustration from ESRI
Layers
Rivers
Capitals
Roads
States
Lakes
Images from ESRI
GIS Features
• Dynamic & Interactive
• You display only what
you want to see
• You can ask the GIS
questions (queries)
• The GIS knows that
every feature on the
map is a separate
“thing”
• Accurate analysis and
measurement
Queries
• Ask the GIS questions…
– “Show me the streams with a pH under 3.”
– “Which counties have more than 50
underground oil tanks?”
– “Which census tracts have cases of West
Nile Virus?”
• The GIS will highlight the features that
fit your criteria
Data
• Vital to the success
of your GIS
• Data are…
– The map features
themselves (e.g.,
county boundaries,
highways or water
wells)
– Attributes for the
features (e.g.,
population, width,
pH)
Database / Spreadsheet
Not easy to interpret
Visualization
Easy to see patterns
Data For GIS Applications
Many Sources
• Digitized and Scanned Maps
– purchased, donated, free (Internet)
– created by user
• Data Bases – Tables of data
• GPS – Global Positioning System
– accurate locations
• Field Sampling of Attributes
• Remote Sensing &
Aerial Photography
Multiple Databases can be
Linked Together
Some Ways GIS is Used
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Emergency Services – Fire & Police
Environmental – Monitoring & Modeling
Business – Site Location, Delivery Systems
Industry – Transportation, Communication, Mining,
Pipelines, Healthcare
• Government – Local, State, Federal, Military
• Education – Research, Teaching Tool, Administration
Wherever Spatial Data Analysis
is Needed