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Lecture 3. ArcGIS Desktop and Geodatabases. This lecture. Exploring ArcGIS desktop The geodatabase data model Building a personal geodatabase Creating features Editing features and attributes Exporting geodatabases Geocoding. ArcGIS Desktop Applications. ArcCatalog ArcMap ArcToolbox.

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Lecture 3

Lecture 3

ArcGIS Desktop and Geodatabases


This lecture
This lecture

  • Exploring ArcGIS desktop

  • The geodatabase data model

  • Building a personal geodatabase

  • Creating features

  • Editing features and attributes

  • Exporting geodatabases

  • Geocoding


Arcgis desktop applications
ArcGIS Desktop Applications

  • ArcCatalog

  • ArcMap

  • ArcToolbox


What do we do in arccatalog
What do we do in ArcCatalog?

  • Manage geographic data

  • Copy, move, delete data

  • Connect to drives on your computer

  • Search for data on your drives or across a network

  • Add/edit metadata

  • Drag data into ArcMap

  • Export data


Arccatalog interface
ArcCatalog interface

Toolbars

Catalog Tree

Catalog display (Preview mode)

‘Geography’ selected


Arccatalog interface1
ArcCatalog interface

Catalog display (Preview mode)

‘Table’ selected


What do we do in arcmap
What do we do in ArcMap

  • Displaying map data

  • Navigating a map

  • Looking at feature attributes

  • Editing features and attributes

  • Query attributes

  • Analyse spatial relationships

  • Design map layouts


Arcmap interface
ArcMap interface

Map display

Table of contents


What do we do in arctoolbox
What do we do in ArcToolbox

  • Tools to convert spatial data between formats

  • Apply map projections

  • Analysis tools

  • Many tools have wizard interface

  • Available from either ArcCatalog or ArcMap


Arctoolbox interface
ArcToolbox interface

ArcCatalog

ArcToolkit window

ArcMap


Extensions
Extensions

  • Extend the capabilities of ArcGIS with a number of products

  • Add from the Tools menu in ArcCatalog or ArcMap

  • Allows selection of products (subject to license)


Toolbars for extensions
Toolbars for extensions

  • Toolbars for these extensions do not automatically open. Use View > Toolbars to open (in ArcMap)


Summary arcgis desktop applications
Summary: ArcGIS Desktop applications

  • ArcCatalog : browse, search, preview, manage and add (to ArcMap) spatial data

  • ArcMap: display data, query attributes, analyse data and design map layouts

  • ArcToolbox: tools for converting, projecting and analysis of data


Geodatabases
Geodatabases

  • New ArcDesktop data format.

  • The future for ArcGIS.

  • Like a Coverage only stored in an Object Orientated Database.

  • Local or Personal Geodatabases vs. SDE Geodatabases shared on a network.

  • SDE databases can be on ArcSDE servers or most other databases. They have locking and versioning to resolve conflicts if more than one person edits a Feature.


Geodatabases1
Geodatabases

  • Can build them from scratch, import from other formats or build using drawings.

  • Keep strict Topological and Data Item constraints on Features.

  • Build Topology and confirm Features have appropriate data as they are edited.

  • Because of this, are used as the basis of Network Analysis.

Geodatabase

Feature Dataset

Feature Class

Features

Workspace

Coverage

Arcs, Polygons etc.

Features


Object orientated databases
Object Orientated Databases

  • Each feature is an Object stored in the Geodatabase.

  • Each Feature is of a certain predefined type, or Class.

  • You can define your own classes, and inherit properties from standard classes.

  • When your classes inherit from another class, they pick up all the Classes Attributes.

  • Classes inheriting from another are known as Subclasses of a Superclass.

ESRI Simple Edge

Feature

integer : length

Building

integer : people

House

Has length

and people

Also has length


Constraints
Constraints

  • Geographical.

  • Class and data types.

  • Variable ranges or categories.


Example
Example

  • Whereas previously you’d make an Arc for a road, you can now make a Road class from the SimpleEdgeFeature superclass.

  • Constrain the Road so it must have a Surfacetype variable picked from a list.

  • Subclass Road to make a Motorway class, with a Number variable which is constrained between 1 and 999.


Building a geodatabase from scratch
Building a Geodatabase from scratch

  • First decide your requirements. Many parts of the creation process cannot be undone later, so get it right first time.

  • What types of data do you want and what constraints?

  • What geographical area do you need?

  • Are you going to do analysis on the data?

  • Build the Geodatabase in ArcCatalog.


Building the geodatabase
Building the Geodatabase

  • Right-click on the Workspace and pick New…

  • Unless a server is running ArcSDE, you’ll only get the chance to create a Personal Geodatabase.

To connect to an existing SDE database, use Database Connections.


Building the geodatabase1
Building the Geodatabase

  • You set constraints by creating Attribute Domains at the Geodatabase level in its Properties.

  • These can be ranges or coded values (categories) data must fall in.

  • These are then applied to specific Feature classes.


Attribute domains
Attribute Domains

  • Maximum and Minimum range, or build codes for categories with associated text descriptions.

  • A Default Value for new Features.

  • Split policy: if a Feature is split, how should the Attribute data be handled in each new Feature?

    • Each gets the default, duplicates the original, or is the original value split on the basis of the divided length/area.

  • Merge policy: if two Features joined, how should the Attribute data be kept?

    • Feature gets the sum of the original, the default, or a length/area weighted average.


Feature dataset
Feature Dataset

  • Right-click Geodatabase>New>Feature Dataset.

  • A collection of Features that share a Spatial Reference, i.e. area and coordinate system. Set this with the Edit button.

Give the Dataset a max/min area and Select a Projection System.


Feature classes
Feature Classes

  • Right-click Feature Dataset > New > FeatureClass

  • Choose a name and set the field.


Feature classes constraints
Feature Classes: Constraints

  • Add new Field.

  • For each pick an Alias (alternative name - can include spaces), a DefaultValue, and an Attribute Domain if you want constraint.

  • Note that Long Integer = Integer used when making domains.

  • Field Properties change when you click on a FieldName.


Table of contents
Table of Contents

  • You should end up with something like the following.

Geodatabase

Feature Dataset

Feature Class


Drawing your geodatabase
Drawing your Geodatabase

  • You can also make your Geodatabase schema (i.e. structure) using a combination of…

  • CASE (Computer Aided Software Engineering) tools.

    • Allow you to draw software and convert it to computer code.

  • UML (Unified Modelling Language).

    • A standard way of drawing Object Orientated things.

ESRI Simple Edge

Feature

integer : length

Occupants

text : owner

integer : others

Building inherits from ESRI

Simple Edge Feature

Building

integer : people

Building has attached Occupants data


Summary
Summary

  • Geodatabases are a new, highly controlled data storage technique.

  • When you build one, you can set Attribute Domains which are constraints that can be applied to Features.

  • You build a Feature Dataset for a particular area / spatial reference.

  • You design Feature Classes e.g. “Roads” and set their constraints.


Shapefiles another commonly used data format
Shapefiles – another commonly used data format

  • Don’t store topological geometry or attribute information

  • A feature is stored a a shape comprising of vector coordinates

  • Fast to draw and edit

  • Support point, line or polygon features

  • Attributes in dBASE format


Other shapefile information
Other shapefile information

  • A shapefile consists of ONLY one feature class whereas geodatabases and coverages may contain several

  • Shapefiles consist of 3 files:

    • .shp main file

    • .shx – index file

    • .dbf – dBASE table

  • Good format to move data about


Geography data input and output
Geography data: input and output

Get geography

Get attributes

  • Getting geography data in…

    • ESRI formats;

    • other formats;

    • digitising.

  • Editing.

  • Exporting data.

Analyse

Output data

Output maps


Getting geographical data in
Getting geographical data in…

  • Creating new data

  • Manual adding.

  • Importing shapefiles, coverages and geodatabases.

  • Importing text files.

  • Importing other formats.

  • Importing from web services.


Creating new data
Creating new data

  • Digitising

    • Produces vector data

    • Usually produced from paper maps, aerial photos or satellite images

  • Heads-up digitising

    • Digitise image on computer screen

  • ArcGIS allows you to create shapes or specify angles and lengths of line segments and whether they are parallel or perpendicular to other segments


Importing
Importing

  • Right-clicking on a Workspace, Geodatabase or Feature Dataser brings up import and export options, so you don’t have to build Geodatabases from scratch.


Importing text files
Importing text files

  • ArcGIS can import ASCII text files (American Standard Code for Information Interchange).

  • ArcToolbox Generate to Coverage Wizard..

NB: Generate files only include geography, not attributes.


Importing other formats
Importing other formats

  • ArcToolbox has a whole set of tools for conversion.

  • You can convert from…

    • Atlas Geo File

    • dBASE file

    • Digital Elevation Model

    • MapInfo Interchange Format

    • TIGER (US Census maps)


Importing from web services
Importing from web services

  • Web services: the Next Big Thing.

  • Data storehouses – you connect via a menu on your GIS, they download the data to you. You don’t save it locally.

  • Ultimately online GIS will do the analysis – you just get the results.

  • Transfer format ultimately GML (Geographical Markup Language – a form of XML).

  • Protocols being put together by the Open GIS Consortium – includes ESRI (and us!).


Geography network
Geography Network

  • ESRI’s online data warehouse.

  • Holds data from many sources.

  • ArcGIS’s ArcMap can access it.

    • File > Add data from Internet

  • ArcExplorer can also contact it.

  • Data transfer written in Java.


Geography network1
Geography Network

  • Pick locality, dataset and it downloads the data from the website into your application.


Geographic data sources

Convert

Raw coordinates

Other vector GIS

Convert

Paper map

Convert

Raster GIS

Digitise

ASCII coordinate file

Image

Digitise

Convert

Shapefile

Import/Export

ArcInfo coverage

ArcInfo grid

Import/Export

Convert

Generate

Manual entry

Load

Geodatabase

Load

Scan

Source: Adapted from Introduction to ArcGIS Part 2 (for ArcView, ArcEditor 8 and ArcInfo 8) v1.2, ESRI (UK) Training course, 2003


Get geography

Get attributes

  • Getting geography data in…

    • ESRI formats;

    • other formats;

    • digitising.

  • Editing.

  • Exporting data.

Analyse

Output data

Output maps


Editing in arcmap
Editing in ArcMap

  • Features can be deleted, moved, divided, merged, resized, reshaped or buffered

  • When features edited, attributes may automatically update eg length, area.

  • Some attribute data may need manual updating

  • Can add new attributes to table


The editor toolbar
The Editor Toolbar

  • All digitising (creating new features or modifying existing ones) is done in an ‘edit’ session

  • Start Editing command - on Editor Toolbar

  • Stop Editing command – also on Editor Toolbar

  • When editing session started you specify:

    • The task – the operation, e.g. Create New Feature

    • The target – layer to which the data is going into

    • The tool – e.g Sketch Tool

  • Errors made in editing can be undone on Standard Toolbar


Adding geodatabase features
Adding Geodatabase Features

  • With a Geodatabase you can pick particular Class Features.

Pressing the Attributes icon brings up a selected Feature’s attributes so you can change them.


Tasks modify features etc
Tasks: Modify features etc

  • There’s a few additional menu items that might help you, if your topology doesn’t clean or you need to edit your data.

  • These are on the Task drop down list of the Editor Toolbar.


Editing existing features in arcmap
Editing existing features in ArcMap

  • Select Features Using a Line / Area : for when you want to select without finishing a sketch.

  • Extend / Trim Features : Select lines, then sketch tool. Draw a line across / beyond selected ones. Trimmed to the right of the sketch line / extended to the line after Finish Sketch selected.

  • Modify feature : select line, right-click where you want to add a vertex. Choose Insert Vertex and Finish Sketch (similar for delete).

  • Can also be picked to drag Vertices or stretch the object depending on setting in Editor > Options > General > Stretch geometry proportionately...


Reshape
Reshape

  • Reshape Feature : used to cut or add to a polygon depending on whether start and end of a sketched line are in or out of the Polygon. Cut Polygon works similarly but splits rather than deleting.

  • Can also be used with the sketch tool to redraw shared boundaries between Polygons in the same way.


Editing topological features
Editing Topological features

  • If you’ve got a Topology built, when you start editing the editor integrates the data. That is, boundaries within the cluster tolerance are snapped so they become identical.

  • The default cluster tolerance is zero. You can set this to something else (usually less than the precision of your map) and manually integrate under Editor > Options… > Topology.

  • Once integrated, there are special tools for dealing with joint Polygon boundaries.


The topology edit tool
The Topology Edit tool

  • The other major tool for shared boundaries.

  • Used for dragging shared vertices or boundaries.

  • Also used under the reshape feature task to select the boundary you want to alter, before redrawing it with the sketch tool.


Autocomplete polygon
Autocomplete Polygon

  • You can also use AutoComplete Polygon from the task list with the sketch tool to add Polygons with shared boundaries.


Get geography

Get attributes

  • Getting geography data in…

    • ESRI formats;

    • other formats;

    • digitising.

  • Editing.

  • Exporting data.

Analyse

Output data

Output maps


Exporting from geodatabase
Exporting from Geodatabase

  • Can use ArcCatalog to export to different formats by right-clicking on the geodatabase…


Geocoding
Geocoding

  • Create spatial data (point features) from information that describes or names a location e.g. an address

  • GIS assigns coordinates to data records

  • Example: Leeds University may want a map of all its students to study distribution. If it has students’ address or postcode then it can make map.


How does it do it
How does it do it?

  • Address table (in database or text format)

  • Reference data on which addresses/postcodes can be located (e.g. street map or postcode boundaries)

  • ArcGIS uses address information in attribute table of reference data to work out where to place point (representing address of customer)

    • Street level reference data will put data at correct location along street

    • Postcode (Zip) reference data will put point at centre of polygon


Do you need anything else
Do you need anything else?

  • Yes, you need an Address Locator

  • The link to ‘Address Locator’ can be found in the catalog tree of ArcCatalog or in the ArcToolbox window

  • Manages existing locators and create new address locators on your computer.

  • Depending on the address locator style you choose, it defines the rules by which addresses are matched from the address table to the reference data and suggests adjustments to enable fuzzy address matching

  • Style chosen depends on geometry in your reference data and format of address data


Matching addresses
Matching addresses

  • Geocoding also called address matching

  • ArcGIS looks at each address in the address file and sees if it can match it with address in reference data

  • Generates a list of probable or possible matching locations (candidate)

  • Candidate given likelihood score (user can choose the score which defines a match)

  • Creates a new data set – point features of each address

  • Can geocode individual addresses using Find dialog


Rematching addresses
Rematching addresses

  • Some addresses will not match – either because reference data is incomplete or because of incorrect entry in address file

  • Can rematch automatically (all at once) after adjusting matching options

  • Rematch interactively (one at a time) – have additional options.


What is the output from geocoding
What is the output from geocoding?

  • Shapefile or geodatabase feature class of points

  • Geocoded data – attributes of the address table, some of the reference data attributes and, optionally, new attributes, e.g. x,y, coordinates of each point.


Summary geocoding
Summary: Geocoding

  • Create point data from address information

  • Require:

    • Address file

    • Reference data

    • Address locator

  • ArcGIS matches address data from address file with address data from reference data

  • Produces a point file in shapefile or geodatabase format


Practical
Practical

  • Create a personal geodatabase

  • Create feature classes

  • Add fields and domains

  • Keep safe for a later practical


Next week
Next week

  • Displaying data

  • Presenting data

  • Querying

  • Attribute tables


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