Introduction to ArcInfo(Workstation)

Getting started with ArcInfo

ArcInfo subsystems

ArcInfo data types

• Supported formats

Vector RasterCoverageMap LibraryArcStorm LibraryTINShapefileSDE LayerDXF File

GridImage

The coverage

• Basic unit for vector data• Can be point, line, polygon• Or region

Linking features and attributes

• Because every feature has a unique identifier, the uniqueness of each feature is guaranteed even if it shares attributes or spatial coordinates with another feature.

The workspace

• A directory (folder)• Used in an ArcInfo

session• Contains geo

datasets and an INFO

Workspace commands

• COPYWORKSPACE• CREATEWORKSPACE• DELETEWORKSPACE• LISTWORKSPACE• RENAMEWORKSPACE• WORKSPACE (or &WORKSPACE)

The geographic database

• Core of a GIS• Completeness• Accuracy

• Spatial data• Attribute data

Operating ArcInfo• Arctools (buttons+menus)

– Limited to functions included

• Command-driven interface– Customized/automated by AML

• Open Development Environment (ODE)– Visual Basics, C, C++, Delphi, Power Builder

ArcInfo Commands

Syntax rules

<cover> <> Required argument

{cover} {} optional argument

{COVER} Uppercase indicates a KEYWORD

{cover} Lowercase substitute the name of an object

<POINT|LINE|POLY> Choices are separated by vertical bars

{POLY|LINE|POINT} For optional argument, first choice is the default

# Optional argument place holder

* Indicates the input for argument comes from the cursor

ArcInfo command example

Arc: USAGE CLEAN

Usage: CLEAN <in_cover> {out_cover} {dangle_length} {fuzzy_tolerance}{POLY|LINE}

Arc: CLEAN STREET STREET2 # # LINE

Getting help for ArcInfo• Get Usage by typing the command

– No argument– Good habit to do that

Arc: BUILDUsage: BUILD <cover> {POLY|LINE|POINT|NODE|ANNO.subclass}

Arc: COMMANDS…..Arc: COMMANDS BBATCH BUFFER BUILD

ARC Macro Language (AML)

• Use to communicate with the ARC system

• Full programming capabilities• ArcInfo commands + OS

commands• AML elements:

– Directives– Functions– Variables

AML directives

• Instruct AML to perform a specific operation

• Start with an ampersand (&)• Examples:

– Arc: &RUN my.aml• Executes an AML program

– Arc: &MENU my.menu• Opens an AML menu

– Arc: &TERM 9999• Sets the terminal type for AML menus

AML functions

• A function performs text substitution• The function name appears in []• A function can return

– A number– A character string– A Boolean value

• Returned value can be used further

Arc: BUILD [response ‘Enter the coverage to BUILD’] POLY

Arc: BUILD [getcov * -line]

AML Variables• A way to store dynamic information• Variable types:

– Character strings– Integers– Real numbers– Boolean expressions

• &SETVAR – to set a variable’s value

• Examples:Arc: &SETVAR COV = LANDUSEArc: &SV COV [response ‘enter cov name:’]Arc: BUILD %COV% POLY

Summary

• Subsystems• Data formats: raster and vector• ArcInfo workspace, INFO directory• Commands, ArcTools• AML:

– directives, – functions, – Variables

• ArcDoc and Command Usage

ArcInfo Data Coverages

Topology

• A mathematical procedure that determines these for geographic features– Spatial properties– Spatial relationships

Spatial Relationship Spatial Property

Each arc has a beginning node and an ending node

Directionality and length of the arc

Arcs connect to other arcs at nodes

Connectivity

Connected arcs form polygon boundaries

Area and perimeter of polygon

Arcs have polygons on their left and right sides

Adjacency or contiguity

Topology-Spatial Property

ArcInfo uses the inherent topologic

relationships of lines and polygons to

provide extensive geographic analysis

capabilities.

Arc-node topology

Polygon-arc topology

Coverage features

• Coverages are either points, lines, or polygons

• A coverage can be both a line coverage and a polygon coverage

• Annotation – Descriptive text associated with other

geographic features• E.g. street names, soil types

Feature attribute tables• FATs are INFO files• Each object is associated with a record in an

FAT• A coverage may have more than one FAT (e.g. a

PAT, AAT, & NAT)

Feature Classes

Feature Attribute Table Name

Description

Point <cover>.PAT Point Attribute Table

Arc <cover>.AAT Arc Attribute Table

Node <cover>.NAT Node Attribute Table

Polygon <cover>.PAT Polygon Attribute Table

Records and feature identifiers

• RECNO – internal record number• COVER# - ArcInfo assigned ID• COVER-ID – user assigned ID

Points

Arcs

Nodes

Polygons

Features with subclasses

Routes

• A coverage can contain multiple route systems– Each is a separate subclass– Each is made up of sections– Each section is made up of arcs or portions of arcs

Route events

Events are located using the route’s measure units and the route contains sections that are associated to the arcs which contain the actual coordinate information.

Regions

Regions contain attribute information but do not contain spatial or coordinate information. Spatial information is determined from the underlying polygons that make up the region.

Annotation

Is a feature typeDoes not represent geography of a featureCan be associated with other existing feature typesOr as independent of any feature

Summary

• Topology in ArcInfo coverage– Nodes, – points, – lines, – polygons, – regions, – subclasses

Exercises

• Ex1 – Understanding spatial relationships

• Ex2 – Introduction to GIS functions• Ex3 - Use the ArcInfo help system• Ex4 - Operate ArcInfo (commands,

AML)• Ex5 - Operate ArcInfo (ArcTools)