19th Advanced Summer School in Regional Science

An introduction to GIS using ArcGIS

Outline First Day

– Introduction to GIS using ArcGIS– Training with ArcGIS– Overview and more advanced directions– Training with ArcGIS

Second Day– GIS topics with ArcGIS: Raster and other data– Training with ArcGIS– Overview and advanced data manipulation– Training with ArcGIS

Early (1507) GIS

Martin Waldseemüller Map

GIS Programs Is GIS a map? Is a map GIS?

– Collect, organize and relate spatial and non-spatial data– Measure and calculate variables in a ‘spatially sensible’ fashion– Make inferences and test hypotheses about relationships that

might have spatial structure, and about the spatial structure itself Map can be viewed as a limited GIS GIS is more than mapping – visual display of spatial

information– Mapping does not necessarily permit measurement/calculation– Mapping rarely ventures into inference or hypothesis testing– Complete GIS implemented using computer programs– Combined graphics editing, database, statistical analysis

This course is focused on use of ArcGIS

There are many other programs worth exploring

There is a “free” way http://www.freegis.org

Google Earth Particularly useful for data display

ArcGIS ArcGIS is a suite of programs for working with

spatial data Three core “workhorse” programs

– ArcCatalog– ArcMap– ArcToolbox

Three useful extras– ArcReader– ArcScene– ArcGlobe

ArcGIS itself comes in 3 levels: view, editor and info

ArcCatalog View folder

contents Connect to

and navigate drives/folders

Launch other ArcGIS applications

ArcCatalog Preview

GIS data Examine

‘Metadata’ Search and

preview online data

Load data layers into ArcMap

ArcMap

The central workspace for analysis an display of geographic data

Table of Contents Tools Map

ArcMap Layers

– ArcMap and all advanced GIS programs adopt ‘layers’ for managing data display

– Layers display can depend on scale

– Layers can be switched on or off

– Layers can be moved up or down

– Layers can be of any data type

ArcToolbox Launched from

ArcCatalog using red toolbox

Provides data and file utilities– Conversion– Projection– Analysis

ArcToolbox For simple projects

these tools are often not required

For large projects with many layers using data from many sources, they can be very useful

Essential for managing projections and coordinate systems

Raster combinations, clipping

Conversions

Working with spatial data Each component of ArcGIS is designed to

facilitate the use and analysis of spatial data

Structure of spatial data

We have choice of which type to use

Spatial Data

Vector Data Raster Data

Data Types: Vector Vector data ideal for representation of

discrete, discontinuous data– Location of a city or structure– Location of a roadway or river– Political boundaries

These examples correspond to the three general types of vector data

Data Types: Vector

Vector– Points– Lines– Polygons

Data Types: Raster Raster represents spatial data as square array of numbers

– Each element of array associated with a pixel– Each pixel has a location – spatial structure– Value of array element represents data at that location

Rasters are natural for representing certain types of data– Elevation– Slope– Temperature– Other continuous variables

Rasters can be used for representing some discontinuous data as well– Transport costs– Land Use

Data Types: Raster Rasters provide direct representation of value, not shape Represent continuous variables or data over space Patterns of values can represent shape Land forms and other structures emerge via patterns

Data Files Vector data and raster data require different

file formats In ArcGIS, vector data are mostly stored in

two formats– Shapefiles (older format – wide compatibility)– GeoDatabase (newer format – more

information) What is the structure of a “shapefile”?

Shapefiles A group of files having the same

prefix but varying file extensions Required:

– .shp - the file that stores the feature geometry. Required.

– .shx - the file that stores the index of the feature geometry. Required.

– .dbf - the dBASE file that stores the attribute information of features. Required.

Shapefiles A group of files having the same prefix

but varying file extensions Optional:

– .sbn and .sbx - the files that store the spatial index of the features.

– .prj - the file that stores the coordinate system and projection information

– .xml - metadata for using shapefiles on the Internet.

– .fbn and .fbx – read-ony indexes– .ain and .aih - active field indexes

Shapefiles

Viewed in Windows Explorer

Viewed in ArcCatalog

Shapefiles Components of a shapefile are called “features” Each feature may have one or more “attributes” Feature attributes are recorded in dbf file Shapefiles can be created within ArcCatalog

– Right click on folder, choose New..Shapefile Shapefiles do not store “topological” information

– Polygons that must share boundaries– Line segments that must be connected– No automatic way to check if these have been

disturbed or incorrectly entered

GeoDatabase GeoDatabase provides an extended format

for vector data Microsoft Access mdb format 28 tables

– GDB_AnnoSymbols to– GDB_ValidRules– More type checking– More checking of topology

Conversion between formats is available in ArcToolbox

Structure of a GeoDatabase Standard

information– Feature Data– Info about

each field Additional

information– Topological

information– Data

validation

Raster Files Files that include geographic location

– ESRI Grid– Geo-TIFF– BIL

Files that present raster data but lack location– jpg– TIFF– Many others

ArcCatalog Test Drive Preview Data View MetaData Create New Files Launch Toolbox Launch ArcMap Add Layers Connect to

Internet– Feature Servers– Map Servers

ArcToolbox Test Drive Projection Conversion Indexing

ArcMap Basics Adding Map Layers Data Frame(s) Frame Properties and Layer Properties Features and Attributes

ArcMap Basics Handling Layers Symbology Transparency View at Map Scale

ArcMap Basics

Selecting Features– Controlling selection layers– Creating new layer from selection

Queries– Basic information– Attribute queries– Spatial queries

Calculating New Attributes Exporting Data

ArcMap Basics Adding Data Frames Working with Layout View Scales, Titles and Legends

ArcMap Intermediate: Data Joining Data

– One to one– One to many

Relating Data Creating Point Shapefile from Data Editing Data

– Creating– Merging– Modifying