Geographic Data Types

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.

70p hongmai1604 18-05-2014 41 4   Download

Local Area Networks (LANs) We have seen how packet switching has contributed greatly to the efficiency and flexibility of ‘wide area’ data networks, involving a large number of devices spread at geographically diverse locations. Packet switching, however, is not so efficient for smaller scale networks, those limited to linking personal computerswithin an office building; that is the realm of an alternative type of packet-switched-like network called a local area network or LAN for short.

11p huggoo 20-08-2010 81 4   Download

The collection of built-in data types in a data base system (e.g. integer, floating point number, character string) and built-in operators (e.g. +, -, *, /) were motivated by the needs of business data processing applications. However, in many engineering applications this collection of types is not appropriate. For example, in a geographic application a user typically wants points, lines, line groups and polygons as basic data types and operators which include intersection, distance and containment.

19p hgiang 11-03-2009 116 4   Download