- GeoGratis - Frequently Asked Questions (FAQ)

Frequently Asked Questions (FAQ)

About Data

About access and use

Miscellaneous

What is the National Topographic System (NTS)?

The National Topographic System (NTS) is a system of divisions used primarily for topographic maps of the Canadian landmass. Maps at the 1:250 000 scale are identified by a combination of numbers and letters from A to P (e.g. 13C).

A map at the 1:50 000 scale corresponds to 1/16 of a map at the 1:250 000 scale, with each unit numbered from 01 to 16. Adding the unit number to the 1:250 000 number produces a unique identifier (e.g. 13C09).

What data-compression mode is used?

Data are compressed using ZIP compression format (.zip).

What delivery medium is available?

FTP (File Transfert Protocol) and HTTP (HyperText Transfert Protocol) are available for data download.

How can I find the magnetic declination for a specific location?

You can look up the magnetic declination for a specific location by using the Magnetic declination calculator on the Web site of Natural Resources Canada's National Geomagnetism Program.

How can I get the coordinates for the neatline of a dataset in the NAD27 and NAD83 reference systems?

You can look up the coordinates for dataset neatlines based on NAD27 or NAD83 on the Web site of the Centre for Topographic Information in Sherbrooke at ftp://ftp.cits.rncan.gc.ca/pub/datum/.

What are the main differences between CanVec and NTDB data?

The document Transition Guide NTDB to CanVec (PDF version, 578 KB) describes major differences existing between the two products.

Compared with NTDB, CanVec data includes the following characteristics:

  1. Better revision cycle: Take advantage of the Geobase initiative and its important group of partners.
  2. Increased accuracy: CanVec data are planimetrically corrected and their planimetric accuracy is equivalent to Landsat 7 orthoimages. By comparaison:
    • NTDB planimetric accuracy < 150 mètres
    • CanVec planimetric accuracy < 30 mètres
  3. Only distributed by NTS 1:50,000 tiles.
  4. Compliance with international standards in geomatics:
    • Simple features and spatial relations
    • Feature catalogue
    • Data Product Specifications
    • Metadata
    • Data format (GML)

From a content standpoint, Canvec data includes 90 topographical features grouped into 11 themes:

  1. Buildings and structures
  2. Energy
  3. Relief and landforms
  4. Hydrography
  5. Industrial and commercial areas
  6. Administrative boundaries
  7. Places of interest
  8. Saturated soils
  9. Toponymy
  10. Transportation
  11. Vegetation

CanVec data are derived from the best data sources available. Data sources used vary according to data files and are among the following:

  1. NTDB 1:50,000 files
  2. GeoBase National Road Network
  3. Files from Landsat 7 update process
  4. Files from new northern mapping process

There is no vertical integration between CanVec data derived from different sources.

Summary table of main differences between CanVec and NTDB data

  NTDB CanVec
Number of themes and features 13 themes, 112 features 11 themes, 90 features
Formats available Shape Shape, GML
Projections available Geographic Geographic
Scales available 1:50,000 and 1:250,000 1:50,000
Planimetric accuracy < 150 metres < 30 metres
Vertical integration between features Complete No integration between features derived from different sources
Revision cycle None Vary according to data sources
Compliance with international standards in geomatics None
  1. Simple features and spatial relations
  2. Feature catalogue
  3. Data Product Specifications
  4. Metadata
  5. Data format (GML)

In order to support transition to the use of CanVec data, a document presenting the complete match between NTDB and CanVec features will be available soon.

What is the liability of the Government of Canada respecting data use?

The Government of Canada shall have no liability for any damage caused by the use of the data. Neither shall the Government have any liability for the use made of the data.

What rights come with an unrestricted-use end-user licence?

An unrestricted-use end-user licence allows the licensee to use, incorporate, grant end-user licences to, modify, improve, develop and distribute the data. The licensee must, however, identify the source of the data on his derived products.

How do I access the digital files from the GeoGratis site?

There are four ways of accessing the digital files:

What are differences between HTTP and FTP downloading methods?

FTP stands for « File Transfer Protocol ». This is a communications protocol dedicated to file exchange and it allows downloads of several files simultaneously. FTP Protocol uses port 21 by default. Most of recent Web browsers authorize FTP connections. The use of a FTP client, in command line mode or with a graphic user interface, usually offers more advanced downloading options such as interrupted download resumption. There are many free FTP clients available such as FileZila and SmartFTP. The use of FTP protocol being rather widespread, it is not very probable that the accesses using it are blocked. This protocol is recommended for download of a large number of files requiring a long period of download.

HTTP stands for « HyperText Transfer Protocol ». This is the communications protocol widely used on the World Wide web and supported by every Web browsers. FTP Protocol uses port 80 by default. The use of this protocol being strongly widespread, it is not very probable that the accesses using it are blocked. This protocol is recommended for download of small number of files.

The data I downloaded are corrupted.

Every effort is made to ensure that the data sets on the GeoGratis portal are structurally sound and compatible with users' needs. In some cases, however, data may be corrupted. If you have discovered such a situation, write to us at geoginfo@nrcan.gc.ca. The corrupted file will be repaired and made available.

I'm receiving an "Error 404: Page not found" message from your portal.

GeoGratis is a dynamic site and access paths change. If you have discovered such a situation, write to us at geoginfo@nrcan.gc.ca. Indicate the link in question and the date of the problem. Thank you for helping us keep the GeoGratis portal in good working order.

Is file format .e00 compatible with ArcView software?

ESRI Arc/Info software export files are in .e00 format. ESRI ArcView software comes with an import program (import71) that converts .e00 files. The ArcView help files explain the process in detail.

Can I buy GeoGratis data on CD-ROM?

GeoGratis operates on a model that minimizes operating costs. The portal has no infrastructure for distributing data on storage media. Geomatics companies can download and convert the data and burn them on CD-ROM for you.

How can I perform format translation or coordinates transformation of the downloaded data?

GDAL/OGR library can be used to perform format translation and coordinates tranformation. This library is a C++ open source library providing read and write access to a variety of vector file formats including Geography Markup Language (GML), ESRI Shape, Oracle and MapInfo MID/MIF or TAB. For more details, see the following link: http://www.gdal.org/ogr/

What is the necessary disk space to store the NTDB data sets for the entire Canada?

Approximately 100 Gig of disk space at the scales 1:50,000 in Shape format not compressed.

Approximately 17 Gig of disk space at the scales 1:250,000 in Shape format not compressed.

For example, here are the sizes of the file 021E05 according to formats:

  • Shape not compressed = 15 MB
What is the necessary disk space to store the CanMatrix data sets for the entire Canada?

Approximately 700 Gig of disk space at the scales 1:50,000 and 1:250,000 in Geotiff format not compressed. Size of the file 021E05 in GeoTiff format = 30MB.

What is the necessary disk space to store the CanImage data sets at the scale 1:50,000 for the entire Canada

Approximately 180 Gig of disk space in GeoTiff format not compressed. Size of the file 021E05 = 15MB.

How can I use the geospatial data?

The purpose of the GeoGratis portal is to make data available. For an answer to this question, contact a discussion forum such as news:comp.infosystems.gis. These forums provide educational resources.

I can't find the data I need on the GeoGratis portal.

If your GeoGratis searches are unsuccessful, we encourage you to visit the GeoConnections Discovery Portal (Canadian Earth Observation Network). There you will find a broad range of digital data and geomatics products and services. A search engine based on keywords, time periods and location uses an established protocol to find access portals and data sets throughout Canada and the world.

For example, you can search just for free data, vector data or data in a specific format.

Where can I find other sources of geospatial data?

You will find a broad range of digital data and geomatics products and services by visiting the GeoConnections Discovery Portal (Canadian Earth Observation Network).

Where can I buy paper topographic maps of Canada?

You will find the list of Regional Distribution Centres at the Canada Map Office.

Where can I find the aerial photographs of the federal government's collection?

The National Air Photo Library archives millions of aerial photographs covering all of Canada.