Introduction to Geographic Information System Qian Yu Department of Geosciences.
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Transcript of Introduction to Geographic Information System Qian Yu Department of Geosciences.
Introduction to
Geographic Information System
Qian Yu
Department of Geosciences
Outline What is GIS? GIS data format Understanding scale Global Positioning System GIS application MassGIS data MassGIS data viewer Google Earth
Digitizing Our World
Two types of information: Location Attribute
Attribute Information:What is it?
Species: OakHeight: 15mAge: 75 Yrs
Location Information: Where is it?
51°N, 112°W
After: ESRI, 2001
What is GIS?
GI System: A GIS is an immensely powerful computer
mapping and analysis system. It 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.
GI Science: research with GIS (Applied Science)
Subsystems of GIS
Input System digitizing, scanning, GPS
Database Management System
Geographic Analysis System
Output System
SoftwareTools
SoftwareTools DatabaseDatabase+
GIS
Results
orSimplification
Abstraction
The real world
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GIS data format - Geographic Data Representation
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1 2 2
1 2
1 2 4
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1
1
Raster Vector
Point
Line
Polygon
500
400
300
200
100
100 200 300 400 500X-Axis
Y-A
xis
Pt 1
Poly 1
Poly 2
Line 1
Pt 1 Building Owner …Line 1 House Length …Poly 1 Fir AreaPoly 2 Pine Area
1 - River
2 - Pine
3 - Fir
4 - House
Scale
Scale: the ratio of the distance on a map to that on the ground between the same two points, in the same units.
Three way to express the scale of a map Representative fraction1:1,000,000
Statement scale One millimeter to one
kilometer
Bar scale
Larger scale (ratio) maps show more detail.
GIS data can be displayed at any scale, but GIS data should not be displayed beyond the accuracy at which the data was developed.
1:100,000 mid-scale
1:250,000 smaller scale
1:24,000 larger scale
1:62,500
1:250,000
1:24,000
More detail
Global Positioning System 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.
12 hours return interval for each satellite (2 complete orbits around the Earth in less than 24 hours).
Functioning satellite GPS systems NAVSTAR
GPS components Satellite segment Control segment
Tracking, communications, data gathering, integration, analysis…
User segmentGPS receivers
Why is GIS important?
Overlay visualizationor modeling
Map production Integration data sources
Spatial analysis and modeling
Exploration and prediction
The application of GIS is limited only by the imagination of those who use it. - Jack Dangermond
Daily life Cartography Environmental management 3D visualization Modeling
GIS Application
3-D Topography
Pioneer Valley
Our daily life need GISDriving 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
3-D Virtual Model for Urban Planning
3D mine with well data
3D urban
Hydrodynamic Modeling: Downstream Flooding
Sacramento, California, USA
(From: U.S. Bureau of Reclamation)
GIS Data in MassGIS Base Map Data
Vector (point/line/area) Features such as roads, streams, and political
boundaries--relatively permanent, widely used features. In shape file or coverage
Raster (image data)
Black & White Digital Orthophotos, Scanned USGS Quads, and Coastal Color Orthophotos,
Available in Tiff and MrSID formats.
Environmental Data 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
Stand-alone, "light," or scaled-down version of ArcView GIS 3.1.1
With much of the map-making functionality Function:
Display all the MassGIS data Change symbolization of the data and add annotation to
the map Create a map layout with map elements such as a scale
bar, north arrow, legend and title Conduct data query and analysis
Google Earth
Client software of web GIS service. The planet's imagery and other geographic information
are put on server and your computer retrieves data through internet real-time.
Function: 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.