Toporama – Frequently Asked Questions

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List of Questions:

1. Are Toporama maps the same as printed topographic maps?
2. Why does the direction of North vary?
3. Why do the maps look a bit different as you zoom in?
4. What data do we use for Toporama?
5. How accurate and how old is the information on Toporama maps?
6. What projection/coordinate system, datum and ellipsoid are used for Toporama?
7. What is the contour interval on Toporama maps?
8. Why are there wooded areas and streams under some roads?
9. Why do so many names on the map look the same?
10. Why are the lines and shapes of features jagged instead of smooth?

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1. Are Toporama maps the same as printed topographic maps?

Toporama maps are similar in appearance to printed topographic maps but are different in other ways. These maps are designed for the Internet so many features will look slightly different. The main reason is that there are limitations in the level of detail that can be shown on the average computer monitor. The small, medium and large map sizes are also much smaller than the average printed topographic map. While printed topographic maps only show a defined area based on the National Topographic Map Sheet Grid, Toporama maps do not have edges. It is like having a seamless map, using 1:250 000 or 1:50 000 scale data for all of Canada, that you view through your Web browser.

2. Why does the direction of North vary?

Toporama maps use a Lambert Conformal Conic (LCC) projection as opposed to the Transverse Mercator (TM) projection used for printed topographic maps. Map projections allow the curved surface of the earth to be placed on a flat surface such as a computer monitor or sheet of paper. Different projections have different characteristics. When a LCC projection is used, North points straight up at the centre of Canada and as you move West, North moves towards the right and as you move East, North moves towards the left. When a TM projection is used on a printed topographic map, North always points straight up regardless of the location. There are two main reasons that that the LLC projection is used for Toporama. The first is to offer a completely “seamless” map for the entire country; it is not subdivided by the traditional topographic map sheet boundaries. The second is to maintain consistency between all five data sets used from the initial national view, through the regional, to the local. Latitude and longitude and UTM coordinates for any location can be determined by using the Get Info from Map tool.

3. Why do the maps look different as you zoom in?

As you zoom in Toporama uses different maps or data which are progressively more detailed. Toporama, for the most part, uses five main base maps or data sets that are derived for the scales of: 1:30 000 000, 1:7.500 000, 1:1 000 000, 1:250 000 and 1:50 000. Some of the changes you will notice are an increase in:

• the detail of the features on the map
• the number of features shown on the map
• the number of map layers, as shown in the legend

4. What data do we use for Toporama?

Toporama uses five main data sets to offer maps that start at a national level and then move to regional and local views. Each offers increasing levels of detail. For the most part, only one main data set is used for each zoom level. However, to improve map clarity, there are situations when features from different data sets appear together as shown in the table that follows.

The five main data sets that appear in Toporama are:

• The Atlas of Canada’s 1:30 000 000 National Scale Framework
• The Atlas of Canada’s 1:7 500 000 National Scale Framework
• The Atlas of Canada’s 1:1 000 000 National Scale Framework
• Centre for Topographic Information's 1:250 000 National Topographic Data Base
• Centre for Topographic Information's 1:50 000 National Topographic Data Base

In addition, the following data is used with the five main data sets above:

• Centre for Topographic Information's GeoBase National Road Network
• Centre for Topographic Information's Canadian Digital Elevation Data
• Centre for Topographic Information's CanImage satellite imagery
• Canadian Geonames Data Base for place and feature names searches

Several abbreviations are used in the table below:

AofC refers to Atlas of Canada
NTDB refers to the National Topographic Database.
NTS refers to the National Topographic System.
NRN refers to the National Road Network.
CDED refers to the Canadian Digital Elevation Data
Min. refers to minimum.
Max. refers to maximum.

The National Topographic Database is the source for the following map features (zoom levels 3,4,5 and 6 only):

CanImage
Limited use roads and trails (zoom levels 4 to 6)
Hydrography
Contours
Built-up areas
Vegetation
Place and features names
Railway
Power network
Constructed features
Designated areas
Water features
Water saturated soils
Landforms

GeoBase is the source for the following map features:

Road network and ferries (except limited use roads and trails) Elevation image

More information on the data used in Toporama can be found on our Map Sources page.

5. How accurate and how old is the information on Toporama maps?

This type of information, or metadata, is available for all Toporama maps. To find it, you will need the National Topographic System (NTS) map number for the area you are interested in. To find the NTS number do one of the following:

• Make sure that the 1:250 000 or 1:50 000 map sheet grid is checked on, in the legend to the right of the map you are viewing.
• Use the “Get Info from Map” tool where the NTS number is listed for the area where you click on the map.

When you have the NTS number, click here to do a search for NTS metadata.

If you are interested in finding this same information about printed topographic maps you purchased, click here to do a search for NTS printed map metadata.

6. What projection / coordinate system, datum and ellipsoid are used for Toporama?

Note: The following information is for the National Topographic Data as seen at map scales of 1:300 000 to 1:20 000.

Projection / Coordinate System:

Name: Lambert Conformal Conic (CANLAMB-83)
False easting: 0.000000
False northing: 0.000000
Central meridian: -95.000000
Standard parallel 1: 77.000000
Standard parallel 2: 49.000000
Latitude of origin: 49.000000
Prime Meridian: 0
Unit of measure: Metre

Datum Parameters:

Name: North American Datum of 1983 (NAD83)
Ellipsoid: GRS1980
Source: US Defense Mapping Agency, TR-8350.2-B, December 1987

Ellipsoid Parameters:

Name: Geodetic Reference System of 1980 (GRS1980)
E_RAD: 6378137
P_RAD: 6356752.31414035
Source: Stem, L.E., Jan 1989, State Plane Coordinate System of 1983

7. What is the contour interval on Toporama maps?

The data used for contours comes from the National Topographic Database and is the same data used for contours on printed topographic maps. As a result, the contour interval on Toporama maps varies in the same way as they do on the printed topographic maps as they were produced individually over many years. The interval can be anywhere from 10 to 200 metres. In some areas of the country contours and spot heights are even shown in feet. This is indicated by the use of a “m” for metres or “ft” for feet beside the contour or spot height number. The numbers will assist in determining the elevation in any particular map.

Index contours are shown as slightly thicker lines to make them more prominent. Due the varying contour interval, index contours can be shown as every fifth, second or even every contour.  The table below shows what contour values have been styled as index contours.

8. Why are there wooded areas and streams under some roads?

In some areas you may see wooded areas, streams and other features appearing underneath roads. The reason is that the roads come from the GeoBase National Road Network and are more up-to-date than the other features from the National Topographic Database. While this may look odd, our research of Toporama users revealed that the value of showing the most up-to-date roads was greater than showing older and incomplete roads that fit perfectly with the other features.

9. Why do so many names on the map look the same?

The names of cities, towns, neighbourhoods and prominent buildings do appear the same (using the same type style) on maps at zoom levels 4, 5 and 6. These names come from the National Topographic Database and there is currently no distinction between types of names in this database. This will change in the future but presents a small limitation at present.

10. Why are the lines and shapes of features jagged instead of smooth?

On a printed topographic map, curved lines and shapes are very smooth. When that same information or data is viewed in a format that is compatible with your Web browser, it gets converted into a picture or image that is made up of small pixels. Because of this, you are not seeing an actual line but a line that is made up of pixels which appears jagged.

If you have any questions about Toporama, please send them by going to the Contact Us page.