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

1 3

1 3

1 3

1 2 2

1 2 2

1 2

1 2 4

1

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.