Toporama – Frequently Asked Questions
List of Questions:
- Are Toporama maps the same as printed topographic maps?
- Why do the maps look a bit different as you zoom in?
- What data do we use for Toporama?
- What projection/coordinate system, datum and ellipsoid are used for Toporama?
- What is the contour interval on Toporama maps?
- Why are there wooded areas and streams under some roads?
- Why do so many names on the map look the same?
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.
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
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 scale National Topographic Data Base
- Centre for Topographic Information's 1:50 000 scale CanVec
More information on the data used in Toporama can be found on our Map Sources page.
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
Name: North American Datum of 1983 (NAD83)
Source: US Defense Mapping Agency, TR-8350.2-B, December 1987
Name: Geodetic Reference System of 1980 (GRS1980)
Source: Stem, L.E., Jan 1989, State Plane Coordinate System of 1983
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 darker lines to make them more prominent.
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 and CanVec. 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.
The names of cities, towns, neighbourhoods and prominent buildings appear the same (using the same type style) on maps at zoom level 4. These names come from the National Topographic Database and there is currently no distinction between types of names in this database. See the table in Question 3 for detailed information on the source of place names in Toporama.
If you have any questions about Toporama, please send them by going to the Contact Us page.
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