Laserfiche WebLink
<br />Introduction to GIS Concepts <br /> <br />This document will introduce you to basic GIS concepts. You will have many opportunities to apply these <br />concepts yourself during the Digital Hazard Data class. <br /> <br />Objective: To understand the basic concepts necessary to use GIS. <br /> <br />Summary: In this document you will learn: <br /> <br />oJ The difference between spatial data and attribute data <br />.J The different types of spatial data you can use in a GIS <br />.J How to get data into a GIS <br />.J What are map coordinate systems, projection. and scale <br />.J What is metadata <br />.J Some of the types of analyses you can perform using a GIS. <br /> <br />Part 1: Spatial data vs. Attribute data <br /> <br />Spatial data are data that provide information about the location, shape. and relationships of geographic <br />features. A map of the United States is an example of spatial data. Using a GIS, you can analyze spatial data, <br />For example, on the map of the United States, you can measure the distance from coast to coast. Or, you can <br />specifY a query to select certain objects on the map - such as the state of Virginia and the nearby states. As a <br />result of this query, the states of District of Columbia, Kentucky, Maryland, North Carolina, Tennessee, and <br />West Virginia would get selected, as shown on the map below, This is possible because the software <br />understands the spatial relationship between the data. <br /> <br /> <br />I.... - <br /> <br />I..... l-flIIM ,.... .... 1....- <br /> <br />"y~ <br /> <br />. "" - - . - <br />f'Wf!dl1' ,:-- ~ ",AI!l .' ~Il'-Il <br />,...... I~. '"S(~ " 3JiM~ <br />. -f.;--.-tM <br />..,...., 0(' , tJ"~ ~. <br /> ---+--- <br />~(...~_.- . .---F~-----~~-" ~.~~_i._~:!.~)1 <br />r........_ ... 'f<,"-.,. TIIo : 4,,,nl~ <br />~~~.----.----- '5' _.._ -L~ ~_m_._ .. -+---~-'~~:_~ <br />-~-- <br />.....'1..,- ". ~ 't All ,w I,nun <br /> <br />Attribute data are tabular files that contain descriptive information that is linked to a specific geographic <br />feature. An example of this is population information about the United States. The population information <br />stored in a table can be linked to the map of the United States. <br /> <br />lof9 <br /> <br />3/17/98 10:05 AM <br />