Download presentation
Presentation is loading. Please wait.
Published byRoberta Leonard Modified over 9 years ago
1
Lecture 4 Data
2
Why GIS? Ask questions Solve a problem Support a decision Make Maps Involve others, share data, procedures, ideas
3
What is a GIS? GISs are simultaneously the telescope, the microscope, the computer, and the Xerox machine of regional analysis and synthesis of spatial data. (Ron Abler, 1988)
4
Definition 1: A GIS is a toolbox "a powerful set of tools for storing and retrieving at will, transforming and displaying spatial data from the real world for a particular set of purposes" (Burrough, 1986, p. 6). "automated systems for the capture, storage, retrieval, analysis, and display of spatial data." (Clarke, 1995, p. 13).
5
Definition 2: A GIS is an information system "An information system that is designed to work with data referenced by spatial or geographic coordinates. In other words, a GIS is both a database system with specific capabilities for spatially-referenced data, as well as a set of operations for working with the data" (Star and Estes, 1990, p. 2).
6
Definition 3: GIS is an approach to science Geographic Information Science is research both on and with GIS. "the generic issues that surround the use of GIS technology, impede its successful implementation, or emerge from an understanding of its potential capabilities." (Goodchild, 1992)
7
Definition 4: GIS plays a role in society Nick Chrisman (1999) “organized activity by which people measure and represent geographic phenomena, and then transform these representations into other forms while interacting with social structures.”
8
Components of a GIS Hardware Software Procedures People with skills to complete tasks Data
9
Hardware Computer, CPU, memory, and monitor Modem and internet connection Data collection devices, GPS, handheld data Scanner or digitizing table Plotter and printer Web Server
10
Software GIS software – range of functions Software extensions – add functions Data viewers – least functionality Single purpose software – make parcel maps Software for the web – ATM, House locators Non-GIS software - database, statistics, image processing
11
Procedures Data input – paper maps, GPS, images Data management - edit and quality Query - Asking map questions Analysis - Spatial, tabular and statistical analysis Map overlay Distance calculations Data output - Map making, on screen, paper, internet
12
People with spatial knowledge Data entry Data quality Analyst Developer / Programmer Database manager Web developer Project manager GIS manager www.gjc.orgwww.gjc.org - GIS jobs listing
13
Data types Maps and Layers Vector Raster TIN 3D Text Metadata
14
Data storage formats Maps and layers Mxd lyr Vector Geodatabase, shapefile, coverage DXF, DWG DGN Raster GRID, sid, img, gif, jpeg Tables Geodatabase, dbf, 3D TIN format
15
Vector data Point - x, y Line - list of x, y coordinates Polygon - list of lines that form a closed area Points 4753456 623412 4753436 623424 4753462 623478 4753432 623482 4753405 623429 4753401 623508 4753462 623555 4753398 623634 LinesPolygons
16
Vector layers
17
Feature class Group of points, lines, or polygons Has a theme-rivers, streets, cities, lakes, states… Makes a layer Point feature class Line feature class Polygon feature class
18
Shapefile Three files,.shp, (.dbf,.shx) Files contain either points, lines, or polygons
19
Layer files File for one layer, stores its symbology.lyr extension, streets.lyr Add to any map or share with friends No data Pointer to data Symbols
20
Geodatabase One file - Access format.mdb file Point, line, & polygon feature classes Tables too
21
What is a database Storage format Container for tables of data Allows queries The sales table contains five tables
22
Table structure Fields Rows Cells
23
A feature class table Has a geometry field You can’t see the actual values, too big
24
Field menu Sort
25
Options menu
26
Select By Attributes
27
Build a SQL expression Field, Operator, Value to search for
28
Records get selected Pop90_SQMI < 30
29
Features get selected too Pop90_SQMI < 30
30
Make table steps Get or make a database Make a table Add fields Add records Add values
31
Make a personal geodatabase
32
A.mdb file is Microsoft Access format
33
Make a new table in the database
34
Name it and default configuration
35
Add fields, type in name and type
36
Data Types and Length
37
Drag the table to ArcMap for editing
38
Add Editor toolbar, Start editing
39
Empty table to start, start typing
40
Type a value into a cell
41
Type in all values
42
Stop editing, save edits
43
Turn off Editor toolbar
44
Make a Geodatabase exercise Make an access database Convert a shapefile Build relationships with other tables Add fields Calculate fields Join fields
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.