# Mapping Census Data in ArcView 3.x

## Presentation on theme: "Mapping Census Data in ArcView 3.x"— Presentation transcript:

Mapping Census Data in ArcView 3.x
Nancy Lemay University of Ottawa Barbara Znamirowski Trent University April 2004 Ontario DLI training

We will try to understand these concepts
Workshop Outline Defining certain concepts and terms: Map scale, coordinate systems, datum and projections. We will try to understand these concepts April 2004 Ontario DLI training

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). April 2004 Ontario DLI training

Map Scales A defined dimensional relationship between reality and the map (Robinson et al., 1995): Verbal: “one cm represents ten kilometers” Representative fraction: 1:10,000 Graphic scale: Area scale: Represents square kilometers 5 1 M e t r s April 2004 Ontario DLI training

Calculate 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. April 2004 Ontario DLI training

Examples small vs. large scale
Small scale: 1:250,000 April 2004 Ontario DLI training

Coordinate 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). April 2004 Ontario DLI training

Types 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) April 2004 Ontario DLI training

Geographic 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 April 2004 Ontario DLI training

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. instead of 60º20'40" April 2004 Ontario DLI training

Example: Converting DMS to DD
60º20'40" degrees minutes seconds 20 minutes.= (20/60) 40 seconds = (40/3600) Add up the degrees to get an answer: 60º = DD April 2004 Ontario DLI training

Ellipsoid (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. April 2004 Ontario DLI training

Datum 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). April 2004 Ontario DLI training

Map 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. Use projected spatial data to calculate distance!! For more information: April 2004 Ontario DLI training

Map Projections Examples
Cylindrical Equal Area Lambert Conformal Conic Preferred for world maps. Mollweide’s Good for directional and shape relations along large east-west mid-latitudes. Good for middle latitudes. April 2004 Ontario DLI training

Different 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. April 2004 Ontario DLI training

ArcView 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. April 2004 Ontario DLI training

StatCan Spatial File Naming Convention
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 April 2004 Ontario DLI training

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 mapping c if detailed interior lakes hydrographic coverage e Ecumene r Road Network Files (RNF and SRNF) For example: gcsd035b02a_e.exe April 2004 Ontario DLI training

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 April 2004 Ontario DLI training

Introduction to ArcView 3.x
April 2004 Ontario DLI training

Tool bar Menu bar Button bar Project window Document windows Status bar

ArcView Documents Layout – integrate documents to create presentation-quality maps View – display, query & analyze themes Table – display attribute data Script – program written in Avenue used to customize the interface, automate common functions or create applications

ArcView Projects Project window Views Tables Charts Layouts Scripts
Displays the names of all project documents & acts as a gateway to all documents in the project. Tables Charts Layouts Scripts April 2004 Ontario DLI training

Views 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 April 2004 Ontario DLI training

Theme Operations You can control visibility and change display order (by dragging) Active themes are raised To make more than one theme active, hold down the Shift key as you click on each theme. When a theme is turned on, ArcView draws it in the map display area. To invoke the Legend Editor Double-click on active theme. April 2004 Ontario DLI training

Symbol Window Legend Editor Fill Palette Pen Palette Marker Palette
Font Palette Color Palette Palette manager April 2004 Ontario DLI training

Let’s Map 2001 Census Data… Proportion of Italian Mother Tongue by Census Tracts Source: Statistics Canada 2001 Census data and cartographic boundary files Author: Nancy Lemay Projection: Lambert Conformal Conic April 2004 Ontario DLI training

Saving the Beyond 20/20 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. April 2004 Ontario DLI training

Importing the CBF .e00 file
Under Start then Programs, you will find under Esri: April 2004 Ontario DLI training

Importing the .e00 file (cont’d)
Click on Browse… to find your .e00 file on your hard drive. Click on Browse… and select where you want to save the new data files and type a new filename in Output Data Source. April 2004 Ontario DLI training

Open ArcView Open ArcView and double-click on Views in the project view. April 2004 Ontario DLI training

Set working 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. April 2004 Ontario DLI training

To add a new theme click on April 2004 Ontario DLI training

Make the theme active Add a check to make the theme active April 2004
Ontario DLI training

Open ArcView 3.x make Tables active in the project window, click on Add. (2) (1) (3) April 2004 Ontario DLI training

Information 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). April 2004 Ontario DLI training

Prepare 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 April 2004 Ontario DLI training

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. April 2004 Ontario DLI training

Open CBF table To open the CBF table go back to the View and click the table icon on the button bar April 2004 Ontario DLI training

Identify common field Find the common field, it should be left justified (string). April 2004 Ontario DLI training

Join the census data with CBF
Destination table Source table April 2004 Ontario DLI training

In the attribute table click on the field you will use to join
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 table Destination table April 2004 Ontario DLI training

Calculate the ratio Open the destination table and under Table select Start Editing April 2004 Ontario DLI training

Add a new field to calculate ratio
Once the table is in edit mode, select Add Field under Edit. April 2004 Ontario DLI training

Define the new field Give the new field a proper name.
Select Number as Type. Type “4” for number of Decimal Places. April 2004 Ontario DLI training

Calculate 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. April 2004 Ontario DLI training

Map the new variable Go back to the View and double-click on the active theme. We will select Graduated Color as a Legend type. April 2004 Ontario DLI training

Select a classification field
Select your newly created variable called Ratio for the Classification Field. Click Apply. April 2004 Ontario DLI training

Choose 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. April 2004 Ontario DLI training

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. April 2004 Ontario DLI training

Final results April 2004 Ontario DLI training

Comparing ArcView 3.x and ArcGIS 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 April 2004 Ontario DLI training

Terminology Project files (*.apr) become map documents (*.mxd)
Projects become maps Views become data frames April 2004 Ontario DLI training

Source view Map display Toolbars April 2004 Ontario DLI training

Importing 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) April 2004 Ontario DLI training

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. April 2004 Ontario DLI training

New terminology April 2004 Ontario DLI training

References Robinson, A.H., et al., Elements of cartography. 6th ed. 1995, New York: John Wiley. 674. April 2004 Ontario DLI training

Partial Credits for Stolen Slides
April 2004 Ontario DLI training