Introduction

As promised a while back, I have compiled a set of GIS files that should be useful for those of us working in the Surveillance Lab. The files are currently located here:

The full list of files can be found at the end of this page. Note that:

  • The files contain only very basic tabular data, i.e., pretty much only the ID fields needed for linking (joining) the geographic features to census data.
  • Census geographic files are available for 1996, 2001 and 2006. Some boundaries changed considerably between censuses.
  • Correspondence files are provided (e.g., to map forward sortation areas to census tracts), but may be incomplete.

The folder GIS_Data contains sub-folders:

  • Correspondence_Files (non-geographic files to convert between geographic units from different sources)
  • DEM_Files (digital elevation models: files to visualize topography)
  • Metadata (manuals and other data about data; incomplete)
  • Orthoimage_Files (satellite imagery of the Montreal area)
  • Shapefile_Files (vector files in shapefile format)

NOTE: I have not attempted any analysis with these files; I have only manipulated them using ArcCatalog and ArcMap. They appeared complete and uncorrupted, however if you experience a problem using them, please report it to me and I will replace the offending file(s).

Sources/Resources

All census data were obtained from the Conference of Rectors and Principals of Quebec Universities (CREPUQ)

Digital elevation model (DEM) files and aerial photography (orthophotos) were obtained from Geobase.

Data Librarian for University:

Anastassia Khouri
Redpath Library
Phone: 514 398-4702
Email: anastassia.khouri@mcgill.ca

“Access to data is restricted to members of McGill University [and other institutions participating in the Data Liberation Initiative (DLI) of Statistics Canada] for teaching and research purposes. Commercial use of the data available on this Web site is forbidden.”

For details, see documents in the Legalities sub-folder of GIS_Data folder.

Notes on Census Geographic Files

When files were available as both geographic and cartographic boundaries, I used the cartographic files. Cartographic files “trim” boundaries to natural features (e.g., shorelines), whereas geographic boundaries do not – they represent a perfect tessellation of the geographic extent, i.e., there are not “gaps” between unit boundaries. Cartographic boundaries work better for visualization; geographic boundaries can work better for certain overlay functions.

Notes on Projection

Details of coordinate systems and projections are listed in File_inventory_20090526.xls in the GIS_Data folder.

Vector files for the Province of Quebec are not projected; they are in the NAD83 coordinate system (geographic). You will need to project these files before using them for any analysis. The choice of projection will depend on the nature of your analysis.

A good (Canada-specific) primer on the need and implications of data projection can be found here:

Vector files for the Census Metropolitan Area of Montreal are projected; they are in the Universal Trans-Mercator system, zone 18 N (UTM18N). Unprojected files are provided if you prefer a different projection system (e.g., MTM).

Approach

  • Identify useful files (based on DB’s emailed list)
  • Obtain data files
    • Vector files
    • Digital Elevation Model files (DEMs)
    • Orthophoto files (satellite imagery)
  • Obtain auxiliary files
    • Metadata files
    • Correspondence/conversion files
    • Data dictionary files
  • Convert all vector files to ESRI shapefile format
  • Remove features falling outside Quebec
  • Unify coordinate system: GCS_North_American_1983
    • (Obtain Quebec-specific transformation method--Not necessary)
  • Create subset of vector files for Montreal (extent determined by Census Metropolitan Area 2006)
  • For Montreal-extent vector files, project to: NAD_1983_UTM_Zone_18N
  • Compile inventory of data

Inventory

Additional information and metadata are included in the GIS_Data folder, and its sub-folders. All census files are provided at two geographic extents: Province of Quebec + Metropolitan Area of Montreal.

  • Census 1996
    • Metropolitan Area
    • Subdivision
    • Tract
    • Forward Sortation Area
    • Hydrology
    • Urban Area
  • Census 2001
    • Block
    • Metropolitan Area
    • Subdivision
    • Tract
    • Dissemination Area
    • Forward Sortation Area
    • Provincial Boundary
    • Road Network
    • Urban Area
  • Census 2006
    • Metropolitan Area
    • Subdivision
    • Tract
    • Block
    • Dissemination Area
    • Forward Sortation Area
    • Provincial Boundary
    • Road Network (Geographic Attribute)
    • Urban Area
  • Non-Census
    • DSP Region Socio-sanitaire (2000)
    • Digital Elevation Model
    • SPOT 4/5 orthoimage


CategoryData

GIS Data (last edited 2010-09-25 11:45:55 by AmanVerma)