INTRODUCTION TO GIS. Dr. Ori Gudes

Transcription

1 INTRODUCTION TO GIS Dr. Ori Gudes

2 Outline of the Presentation What is GIS? What s the rational for using GIS, and how GIS can be used to solve problems? Explore a GIS map and get information about map features. Preview geographic data and metadata. Add data to a map. Describe the structure of a GIS map. Explain how a GIS represents real-world objects. Change the way features are drawn on a map. Access feature information in different ways. Describe spatial relationships of map feature.

3 What is GIS?

4 What s the rational for using GIS?

5 What s the rational for using GIS? Almost everything that happens, happens somewhere. Knowing where something happens can be critically important

6 A GIS performs six fundamental operations Capture data You can add data from many sources to a GIS, and you can also create your own data from scratch. You will learn about getting data into a GIS in Modules 4 and 5. Store data You can store and manage information about the real world in ways that make sense for your application. You will learn about organising data in Module 4. Query data You can ask complex questions about features based on their attributes or their location and get quick results. You will gain experience with querying in Module 6. Analyse data You can integrate multiple datasets to find features that meet specific criteria and create information useful for problem solving. You will perform analysis in Modules 6 and 7. Display data You can display features based on their attributes, a powerful representation feature you'll come to appreciate. You will learn how to symbolise features in different ways in the next module / presentation (Module 2). Present data You can create and distribute high-quality maps, graphs, and reports to present your analysis results in a compelling way to your audience. You will learn how to create a report in Module 6 and how to design an effective map in Module 8.

7 The six components parts of GIS

8 Advantages of GIS Integrates spatial and other (aspatial) data across a diverse range of applications Identifies connections between activities based on geographic proximity Manipulate and display geographic knowledge Provides visualisation of administrative records A tool for enhancing decision making Increases ability to model science and management problems A catalyst to further development

9 Who uses GIS?

10 Example of GIS use

11 Application of geospatial technology or GIS The geospatial revolution clip

12 Two main formats used in GIS: Vector and Raster A Raster format is defined as: any type of digital image represented in grids. Raster data type consists of rows and columns of cells, with each cell storing a single value. Raster data can be images (raster images) with each pixel (or cell) containing a colour value. Vector format is defined as: A Geometrical shape, it is linked to a row in a database that describes its attributes. For example, a database that describes lakes may contain a lake's depth, water quality, pollution level.

13 Vector and Raster data layers

14 Raster Format Discrete (Integer raster) Continuous surface

15 Advantages (Raster) Simple Data Structure. Cheap Technology. Analysis is Simple. Same grid cell for several attributes. Disadvantages (Raster) Large Data Volume. Inefficient use of computer storage. Difficult network analysis. Less accurate or attractive maps. Loss of information when using large cells.

16 Vector format composed of Geographical entities Attributes

17 Geographical Entities

18 The spatial glue that integrates layers 8/9/2016 A common coordinate system ties layers together for: Viewing Analysis Building relationships This is the glue that holds the GIS together 18

19 Attributes Alpha-numeric data such as: text, numbers, categorical values, etc.

20 Advantages (Vector) Good Representation of data. Use small File Size. Accurate map output. Disadvantages (Vector) Complex Data Structure. Expensive Technology. Analysis is Complex.

21 Spatial Relationships Between Geographical Entities Distance Containment Intersection Adjacency

22 GIS Technology Trends Depth of understanding 8/9/2016 Source: 22

23 Explosive growth in GIS There is a large and growing number of GIS applications due to: greater awareness and knowledge of the potential of GIS; good and cost-effective technology to support the applications; availability of digital data at reduced prices; ease of use of commercial systems (desktop, web mapping, etc.); choice of software and reduction in price. 8/9/

24 Growth of GIS The Future Mobile Web Based Intranet Internet Mainframe Desktop 8/9/

25 Review GIS can organise and stores information about the world as a collection of thematic layers. Each layer contains features with the same shape and attributes, all located within a common geographic area. Each feature is assigned a unique numerical identifier and is characterised by a unique location in space and a corresponding record in a table. Features can be stored in GIS as three primary shapes: points, lines, or polygons.

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29 Thank you

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