april 2004ontario dli training mapping census data in arcview 3.x nancy lemay university of ottawa...

April 2004 Ontario DLI training

Mapping Census Data Mapping Census Data in ArcView 3.xin ArcView 3.x

Nancy Lemay

University of Ottawa

Barbara ZnamirowskiTrent University


Workshop OutlineWorkshop Outline

• Defining certain concepts and terms: Map scale, coordinate systems, datum and projections.

We will try to understand

these concepts


Workshop Outline (cont’d)Workshop Outline (cont’d)

• Understanding different file formats:

- “.e00”, “.shp”, “.shx”, “.dbf”, “.sbn” and “.sbx”.

• Introduction to ArcView and its components.

• Hands-on exercise using census data and cartographic boundary files (CBF).


Map ScalesMap ScalesA defined dimensional relationship between reality and the map (Robinson et al., 1995):

a) Verbal: “one cm represents ten kilometers”

b) Representative fraction: 1:10,000

c) Graphic scale:

d) Area scale: Represents square kilometers

5000 0 5000 10000 Meters


Calculate Map ScalesCalculate Map Scales

• For example, if 2 cm on a map represents 1 km on the ground the scale would be 2 cm = 1 km, or...

• Scale is “unitless” because it is a ratio.


Examples small vs. large scaleExamples small vs. large scale

Small scale: 1:250,000

Large scale: 1:50,000


Coordinate systemsCoordinate systems• A coordinate system is a reference system based on

mathematical rules for specifying positions (locations) on the surface of the earth. The coordinate values can be spherical (latitude and longitude) or planar (such as Universal Transverse Mercator).

• A coordinate system is usually defined by a datum, ellipsoid and projection, and is specified in terms of units (e.g. degrees, meters).


Types of Coordinate SystemsTypes of Coordinate Systems

Geographic coordinate system:– Uses latitude and longitude for locating

positions on the uniformly curved surface of the earth.

Rectangular/plane coordinate systems:– Used to locate positions on a flat map.

– For example Universal Transverse Mercator (UTM)


Geographic Coordinate SystemGeographic Coordinate System• The Equator (latitude) and Prime Meridian (longitude) are the

reference points. Usually Greenwich, England is the Prime Meridian.

• The Cartographic Boundary Files, the Road Network Files and the representative points are disseminated in latitude/longitude coordinates.

Prime meridian

Equator


Decimal Degrees (DD)Decimal Degrees (DD)

• Decimal degrees are similar to degrees/ minutes/seconds (DMS) except that minutes and seconds are expressed as decimal values.

• Decimal degrees make digital storage of coordinates easier and computations faster.

60.34444 instead of 60º20'40"


Example: Converting DMS to DDExample: Converting DMS to DD

20 minutes.= 0.33333 (20/60)40 seconds = 0.01111 (40/3600)

Add up the degrees to get an answer:60º + 0.33333 + 0.01111=60.34444 DD

60º20'40"degrees

minutes

seconds


Ellipsoid (Spheroid) and GeoidEllipsoid (Spheroid) and Geoid

• Ellipsoid - used as a reference of the earth’s surface for the mathematical model of the earth. Mathematical approximation of the geoid.

• Geoid - estimates the earth’s surface using mean sea level of the ocean with all continents removed.


DatumDatum

• Geodetic reference system that specifies the size and shape of the earth.

• Base point from which the latitude and longitude of all other points on the earth's surface are referenced.

• Two types of datums: (1) Earth-centered (WGS84, NAD83), (2) Local (NAD27, ED50).

• The spatial data disseminated for the 2001 Census are based on the North American Datum of 1983 (NAD83).

http://www.geod.nrcan.gc.ca/index_e/geodesy_e/reference04_e.html


Map ProjectionsMap Projections• Process of transforming and representing positions on the

earth's three-dimensional curved surface to a two-dimensional (flat) surface.

• The process is accomplished by a direct geometric projection or by a mathematically derived transformation.

For more information: http://mac.usgs.gov/mac/isb/pubs/MapProjections/projections.html

Use projected spatial data to calculate distance!!


Map Projections ExamplesMap Projections Examples

Lambert Conformal ConicCylindrical Equal Area

Mollweide’s

Good for middle latitudes.

Good for directional and shape relations along large east-west mid-latitudes.

Preferred for world maps.


Different File FormatsDifferent File Formats

Shapefile “.shp” is used in ArcView and ArcGIS and is accompanied by the following auxiliary files:

• “.dbf” the dBASE file that stores the attribute information of features. Required.

• “.shx” the file that stores the index of the feature geometry. • “.sbn & .sbx” the files that store the spatial index of the features. • “.prj” - the file that stores the coordinate system information.• “.xml” - metadata for ArcInfo 8.0, for using shapefiles on the

Internet.

Coverages are often published in a compacted form with the extension “.e00”:

• Proprietary file format used to distribute Arc/Info datasets. Topology and attributes are properly maintained in this format.


ArcView Project FileArcView Project File

• The ArcView “.apr” file contains the project information.

• Features are stored:

• view properties

• theme information

• layout information

• other types of information are stored.

• Return to the project without having to re-load all the associated files.


StatCan StatCan Spatial File Naming Spatial File Naming ConventionConvention

First Character: projection of file: “g” if projection is Geographic Latitude/Longitude and “l” if projection is Lambert Conic Conformal.

Next three characters: primary geographic boundary of file, for example “csd”.

For example:gcsd035b02a_e.exe


Next three Numbers: geographic code of coverage, for example 035.

Next character: file type (based on 1996 codes).a if digital boundary file (for Dissemination Warehouse only) (DBF in 1996)b if Cartographic Boundary File, detailed coverage for large-scale mappingc if detailed interior lakes hydrographic coveragee Ecumener Road Network Files (RNF and SRNF) For example:

gcsd035b02a_e.exe


Following two numbers: dissemination year (date stamp for versioning)

– The choices are: 01 if disseminated in 2001, 02 if disseminated in 2002, 03 if disseminated in 2003 etc.

Next character: file format: – “a” ARC/INFO® ArcGIS Export File (e00), “m” MapInfo® Export

File (mid & mif)

Final two characters: language– _e English– _f français

For example:gcsd035b02a_e.exe


IntroIntroduction duction to ArcView 3.x to ArcView 3.x

Button bar

Project window

Menu barTool bar

Document windows

Status bar

ArcView DocumentsArcView Documents View – display, query & analyze themes Layout – integrate documents to create presentation-

quality maps

Table – display attribute data

Script – program written in Avenue used to customize the interface, automate common functions or create applications


ArcView ProjectsArcView Projects

Views

Tables

Charts

Layouts

Scripts

Project window

Displays the names of all project documents & acts as a gateway to all documents in the project.


Views and ThemesViews and Themes• Theme: A GIS links sets of features and their attributes and manages

them together in units called themes. Each theme has a title and a legend in the view’s Table of Contents.

Themes


Theme OperationsTheme Operations

When a theme is turned on, ArcView draws it in the map display area.

Active themes are raised

To make more than one theme active, hold down the Shift key as you click on each theme.

To invoke the Legend Editor Double-click on active theme.

You can control visibility and change display order (by dragging)


Symbol WindowSymbol Window Fill Palette Pen Palette

Palette manager Color Palette Font PaletteMarker Palette

Legend Editor


Let’s Map 2001 Census Data… Let’s Map 2001 Census Data…

Italian Mother Tongue Normalized by Total Population0 - 0.0050.005 - 0.0140.014 - 0.0310.031 - 0.0750.075 - 0.146

HydrographyStreets

N

20 0 20 40 Kilometers

Source: Statistics Canada 2001 Census data and cartographic boundary filesAuthor: Nancy LemayProjection: Lambert Conformal Conic

Proportion of Italian Mother Tongue by Census Tracts


Saving the Saving the Beyond 20Beyond 20/20 table /20 table

• Open the B20/20 table « .ivt » for:

– Profile of Citizenship, Immigration, Birthplace, Generation Status, Ethnic Origin, Visible Minorities and Aboriginal Peoples, for Census Metropolitan Areas, Tracted Census Agglomerations and Census Tracts, 2001 Census - Cat. No. 95F0489XCB01005

• After subsetting the B20/20 table to include only Ottawa Census Tracts, save the table as a « .dbf » file.


Importing the Importing the CBF .e00 fileCBF .e00 file

a) Under Start then Programs, you will find under Esri:


Importing the .e00 file (cont’d)Importing the .e00 file (cont’d)

b) Click on Browse… to find your .e00 file on your hard drive.

c) Click on Browse… and select where you want to save the new data files and type a new filename in Output Data Source.


Open ArcViewOpen ArcView

• Open ArcView and double-click on Views in the project view.


Set Set wworking directory…orking directory…

When starting a project in which new data needs to be created, the working directory has to be set so that ArcView knows where to store the files.

File -> Set Working Directory

After this has been selected a dialog will appear where

the working directory can be set.


Load cartographic boundary fileLoad cartographic boundary file

To add a new theme click on


Make the theme activeMake the theme active

Add a check to make the theme active


Add table to your new projectAdd table to your new project

• Open ArcView 3.x make Tables active in the project window, click on Add.

(1)

(2)

(3)


Information on Table JoinsInformation on Table Joins

• A join function is provided in ArcView so that the census data can be appended to the attribute table of the CBF.

• In order to join the two tables, a common field containing the same values must be identified. Please note that the name of the field does not have to be the same, but the values in the field must be of the same type (string vs number).


Prepare census table for a joinPrepare census table for a join

• To Edit the census table click under Table –> Start Editing

• Under Edit click Add Field…• Type « CTUID » for Name, select « String » as a Type

and « 10 » for Width.

• Click under Table –> Stop Editing


• We need to convert these census tract labels to recreate the common field in our profile data.

• Click Calculate in the Field menu. The calculation is based on the following instruction: CTUID=505.AsString+[Geography].Left(7), which means that the CTUID string is created by adding the Ottawa CMA code as a string to the left-most 7 characters in each of the Geography labels.


Open CBF tableOpen CBF table

To open the CBF table go back to the View and click the table icon on the button bar


Identify common fieldIdentify common fieldFind the common field, it should be left justified (string).


Join the census data with CBFJoin the census data with CBF

Source table

Destination table


• In the attribute table click on the field you will use to join. You know the field is selected when it is sunken and darker than the surrounding fields.

• In the shapefile table click on the same field. Click Table in the menu and then Join or click on the following button:

Source tableDestination table


Calculate the ratioCalculate the ratio

Open the destination table and under Table select Start Editing


Add a new fieldAdd a new field to calculate ratio to calculate ratio

Once the table is in edit mode, select Add Field under Edit.


Define the new fieldDefine the new field

• Give the new field a proper name.

• Select Number as Type.

• Type “4” for number of Decimal Places.


Calculate the new variableCalculate the new variable

• Under Field select Calculate…• Let’s calculate the ratio of people who have Italian as a mother tongue

and the total population.


Map the new variableMap the new variable

• Go back to the View and double-click on the active theme.

• We will select Graduated Color as a Legend type.


Select a classification fieldSelect a classification field

• Select your newly created variable called Ratio for the Classification Field. Click Apply.


Choose a projectionChoose a projection

• A projection is needed for publication purposes and for calculating distances.

• Under View select Properties.

• Select kilometers as Map Units and Distance Units.

• Click on Custom and select Lambert Conformal Conic.


Optional: add hydrographyOptional: add hydrography

• Click on the to add the hydrography shapefile.

• Remember to make it active by adding a checkmark.

Double-click on the active theme to activate the Legend Editor and double-click on the the color box below Symbol. Click on the paint brush to select a new color. Click Apply.


Final resultsFinal results


Comparing ArcView 3.x and Comparing ArcView 3.x and ArcGIS 8.xArcGIS 8.x

• Same basic functionality as 3.x

• Separate software modules for organizing files (ArcCatalog), accessing tools (ArcToolbox) and working with data (ArcMap).

• Projection-on-the-fly

• Direct read of more data formats

• Can import 3.x project files and legend files


TerminologyTerminology

• Project files (*.apr) become map documents (*.mxd)

• Projects become maps

• Views become data frames


InterfaceInterface

• No more project window

• Table of contents

– Display view

– Source view

• Map display

• Toolbars


ImportingImporting

• Simple to do, but it has been known to cause problems.

– Primarily, cannot import all 3.x views

• Import 3.x project files (*.apr)

• Import 3.x legend files (*.avl)


Project file problem…Project file problem…

• ArcMap allows the storing of relative path names.

• Use “Set Data Source” to find lost layers or simply remove and re-add the lost layer.


New terminologyNew terminology

• http://www.esri.com/news/arcuser/0402/files/talking.pdf


References References

• Robinson, A.H., et al., Elements of cartography. 6th ed. 1995, New York: John Wiley. 674.


Partial Credits for Stolen SlidesPartial Credits for Stolen Slides

• http://tdr.tug-libraries.on.ca/HELPS/gishelp.htm

• http://prod.library.utoronto.ca:8090/maplib/ArcMap_Guide.pdf

• http://www.ideal.forestry.ubc.ca/cons340/Lecture03.pdf

• http://maps.nrcan.gc.ca/maps101/scale.html

• http://www.uottawa.ca/academic/arts/geographie/lpcweb/web2320/


More info on making your projects portable:More info on making your projects portable:

• http://www.wlu.ca/~wwwgeog/special/geomatics/pdf/transportable.pdf

• http://www.esri.com/industries/k-12/download/docs/transapr.pdf

Importing ArcView GIS Projects into ArcGIS

• http://www.esri.com/news/arcuser/0701/avconvert.html

april 2004ontario dli training mapping census data in arcview 3.x nancy lemay university of ottawa...

Documents

ontario dli training

census table

editing slide

attribute table

theme active slide

table icon

shapefile table

button bar slide