Transcript Slide 1

Introduction to
Geographic Information System
Qian Yu
Department of Geosciences
Outline
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What is GIS?
GIS data format
Understanding scale
Global Positioning System
GIS application
MassGIS data
MassGIS data viewer
Google Earth
Digitizing Our World
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Two types of information:
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Location
Attribute
Location Information:
Where is it?
Attribute Information:
What is it?
Species: Oak
Height: 15m
Age: 75 Yrs
51°N, 112°W
After: ESRI, 2001
What is GIS?
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GI System:
 A GIS
is an immensely powerful computer
mapping and analysis system.
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links geographic locations with information
about them so you can create maps and analyze
information in new ways.
 Techniques
for acquisition, storage, manipulation,
analysis, and display of spatial data.
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GI Science: research with GIS (Applied Science)
Subsystems of GIS
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Input System
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digitizing, scanning, GPS
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Database Management System
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Geographic Analysis System
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Output System
GIS
Abstraction
or
Simplification
Software
Tools
+
The real world
Results
Database
GIS data format - Geographic Data Representation
Raster
Vector
1 2 3 4 5 6 7 8 9 10
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Poly 1
400
3
1
Line 1
500
Y-Axis
1
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1
300
Poly 2
200
Pt 1
Point
Line
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Polygon
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1
1 - River
2 - Pine
3 - Fir
4 - House
100
Pt 1
Line 1
Poly 1
Poly 2
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300
X-Axis
Building
House
Fir
Pine
400
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Owner
Length
Area
Area
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Scale
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Scale: the ratio of the distance on a map to that on the
ground between the same two points, in the same units.
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Three way to express the scale of a map
 Representative
 Statement
 Bar
scale
fraction
1:1,000,000
One millimeter to one kilometer
scale
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Larger scale (ratio) maps show more detail.
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GIS data can be displayed at any scale, but GIS data
should not be displayed beyond the accuracy at which the
data was developed.
1:250,000 smaller scale
1:24,000 larger scale
1:62,500
1:24,000
More detail
1:100,000 mid-scale
1:250,000
Global Positioning System
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GPS a global satellite based
radio-navigation
system/technology, consisting of
24 orbiting satellites at an altitude
of 20,000 km in space, in six
different orbital paths/plane and
their ground stations.
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12 hours return interval for each
satellite (2 complete orbits around
the Earth in less than 24 hours).
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Functioning satellite GPS systems
NAVSTAR
GPS components
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Satellite segment
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Control segment
Tracking, communications, data
gathering, integration, analysis…
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User segment
GPS receivers
Why is GIS
important?
Overlay visualization
or modeling
 Map
production
 Integration
data sources
 Spatial
analysis and
modeling
 Exploration
and prediction
GIS Application
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Daily life
Cartography
Environmental management
3D visualization
Modeling
The application of GIS is
limited only by the
imagination of those who
use it.
- Jack Dangermond
3-D Topography
Pioneer Valley
Our daily life need GIS
Driving direction
GIS for showing where you are and
the best route from A to B
Locating a store
GIS for mapping shops near you
Combing Data From Many Sources
3-D Display
View large data sets seamlessly
3D mine with well data
3D urban
3-D Virtual Model for Urban Planning
Hydrodynamic Modeling:
Downstream Flooding
Sacramento, California, USA
(From: U.S. Bureau of Reclamation)
GIS Data in MassGIS
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Base Map Data
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Vector (point/line/area)
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Features such as roads, streams, and political
boundaries--relatively permanent, widely used features.
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In shape file or coverage
Raster (image data)
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Black & White Digital Orthophotos, Scanned USGS
Quads, and Coastal Color Orthophotos,
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Available in Tiff and MrSID formats.
Environmental Data
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Developed, maintained and updated by EOEA and its
agencies for the purpose of enforcing environmental
regulations or in support of various types of environmental
analysis.
MassGIS Runtime Data Viewer
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Stand-alone, "light," or scaled-down version of ArcView
GIS 3.1.1
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With much of the map-making functionality
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Function:
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Display all the MassGIS data
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Change symbolization of the data and add annotation to the map
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Create a map layout with map elements such as a scale bar, north
arrow, legend and title
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Conduct data query and analysis
Google Earth
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Client software of web GIS service.
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The planet's imagery and other geographic information are put
on server and your computer retrieves data through internet
real-time.
Function:
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Fly from space to your neighborhood. Type in an address and
zoom right in.
Search for schools, parks, restaurants, and hotels. Get driving
directions.
Tilt and rotate the view to see 3D terrain and buildings.
Save and share your searches and favorites. Even add your own
annotations.