Natural Resources Canada describes a topographic map as depicting, in detail, ground relief (landforms and terrain), drainage (lakes and rivers), forest cover, administrative areas, populated areas, transportation routes and facilities (including roads and railways), and other man-made features.
The Government of BC website has a link to the Base Map Online Store where anyone can download a topographic map, for free, for any area of BC.
But what do you need to know to understand what the map means? When looking at a topographic map, you will see the following standard features (among others):
CONTOUR LINES
Contour lines connect points with the same elevation. If the lines are closer together, the steeper the slope and the greater the change in elevation. If the lines are farther apart, this shows a gentle slope and a slow elevation change.
Contour lines indicate the shape of the terrain with rough circles likely showing a peak. Circles with tick marks generally show a depression rather than a peak.
Every fifth contour line appears to be a heavier line – called an Index Line. These lines generally identify the exact elevation of that line.
Interval lines (usually marked on the legend or map index), show how many vertical feet are between lines. If the interval map shows 40, this means that each line is 40 vertical feet higher or lower than the line above or below it.
MAP SCALES
These tell you how detailed the map is. For example:
If the scale is 1:20,000 then each inch on the map is equivalent to 20,000 inches of real terrain. The level of detail is greater than if the scale were 1:50,000 as it covers a smaller land area.
A representative scale is a ruler noted on every map which gives an idea of how many miles or kilometres one map inch covers.
COLOR CODING
Topographic maps use a standard colour-coding system to identify different aspects or features:
Black – identifies cultural features such as buildings, railways or power lines.
Blue – identifies water features such as lakes, rivers, waterfalls, swamps or marshes.
Green – identifies vegetation, orchards, wooded areas or locations such as vineyards.
Red – identifies roads, highways, major transportation routes and even interchange exit numbers.
LEGENDS AND ORIENTATION
The map legend explains what each of the lines, symbols and other map characteristics are.
Generally, topographic maps are oriented to true north, while compasses are oriented to magnetic north. Because these are not usually aligned perfectly, you may need to figure out the difference between the two so you can adjust your bearings accordingly.
Declination is the angle of deviation between the two points and is constantly changing because the earth’s magnetic field is also constantly changing. The difference between true north and magnetic north also varies depending on where you are on earth.
Many other features are found on topographic maps but the ones identified here will get you started.