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After this lecture you should be able to: Describe the primary Vector data models used in GIS and give examples, describe raster data models and give examples, describe TIN data models, explain “topology”, describe the main file formats used in GIS. | Lecture 3: GIS Data Models AIM: To introduce various GIS data models After this lecture you should be able to: Describe the primary Vector data models used in GIS and give examples Describe raster data models and give examples Describe TIN data models Explain “topology” Describe the main file formats used in GIS Introduction to GIS In this lecture you will be introduced to some of the basic principles of Geographical Information Systems (GIS). A definition will be established and a brief description of the historical developments will be provided. Finally some of the main components required to run a successful GIS will be defined. This includes the types of data that a good GIS should be able to handle. The practical session that accompanies this lecture will allow you to explore the Desk Top GIS MapInfo. Full notes are provided to teach you how to apply some of the GIS theory that is introduced in these lectures. Graphic Features Objects which are shown on a map are called . | Lecture 3: GIS Data Models AIM: To introduce various GIS data models After this lecture you should be able to: Describe the primary Vector data models used in GIS and give examples Describe raster data models and give examples Describe TIN data models Explain “topology” Describe the main file formats used in GIS Introduction to GIS In this lecture you will be introduced to some of the basic principles of Geographical Information Systems (GIS). A definition will be established and a brief description of the historical developments will be provided. Finally some of the main components required to run a successful GIS will be defined. This includes the types of data that a good GIS should be able to handle. The practical session that accompanies this lecture will allow you to explore the Desk Top GIS MapInfo. Full notes are provided to teach you how to apply some of the GIS theory that is introduced in these lectures. Graphic Features Objects which are shown on a map are called graphic features or features. These features may be natural or man made objects. Digital representation of physical or man made elements: Graphic Features Vectors Points or Nodes Lines or Arcs Polygons Raster Cells or Pixels Images Digital Orthophotography Geographic Data Types Images Vector Raster (GRID) Attributes TIN (Triangulated Irregular Network) Annotation © Paul Bolstad, GIS Fundamentals Geographic Data Types © Paul Bolstad, GIS Fundamentals The raster DEM (digital Elevation Model) you see above as a picture file, in essence it is made up of numbers. A number represent a cell. Those are called raster cells. Earlier you have seen if you go on zooming your picture, you will end up seeing square blocks which is called the raster cells or pixels. We will learn more about pixels later. DIGITAL SPATIAL DATA RASTER VECTOR Real World Source: Defense Mapping School National Imagery and Mapping Agency This is an illustration of transferring a real world geographic area into the .
