Map scale and geographic coordinates – measuring distance on a map
GeographyMaps & MappingAges 11–12
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Maps & Mapping
A hand-drawn map (river, road, village, school, lake, hill) with a latitude–longitude grid and a scale bar. Students drag two points A and B; the ruler shows the distance in centimetres on the map, and the program converts it to ground distance using the chosen scale (1:10 000 to 1:1 000 000) and reads the geographic coordinates (degrees, minutes) of both points. Change the scale to see how the same 1 cm on the map stands for a different ground distance. A second screen shows an imaginary 1:50 000 map in the style of the Ordnance Survey, with a 1 km grid, contours, standard symbols and a key: students give 4- and 6-figure grid references (eastings before northings), find symbols, measure straight-line distance with a ruler and the scale, and give directions on an 8- or 16-point compass and three-figure bearings, with feedback and a score.
Lesson: Map scale; the graticule (meridians and parallels), geographic coordinates
What it shows
A map scale tells how many times the ground has been reduced: at 1:50 000, 1 cm on the map stands for 500 m, so ground distance equals map distance times the scale denominator, and a smaller denominator means a larger, more detailed map. Positions can be given as latitude and longitude, or on a national grid: eastings are read along the bottom first, then northings up the side. A 4-figure reference names a 1 km square; a 6-figure reference adds tenths to locate a point to the nearest 100 m. Directions use 8 or 16 compass points, or a three-figure bearing measured clockwise from north.
How to use
On Scale and coordinates, drag A and B onto features to read the map distance and the ground distance, change the Scale, and read latitude and longitude. On Grid references, choose a Task and press New task: type a grid reference, click a symbol, drag the ruler ends P and Q to measure a distance, or pick a direction, then press Check. Tap the map to read a grid reference and the height; Key shows the symbols.
Parameters you can change
- Map scale 1:10 000, 1:25 000, 1:50 000, 1:100 000, 1:500 000, 1:1 000 000
- Show latitude/longitude grid
- Show scale bar
- Latitude of the map's bottom-left corner -80–80 °
- Longitude of the map's bottom-left corner -180–180 °
- Screen Scale and coordinates, Grid references (OS-style map)
- Grid-reference task Mixed tasks, 4-figure grid reference, 6-figure grid reference, Find a symbol, Straight-line distance, Direction (8 points), Direction (16 points), Bearing
Questions to explore
- On a 1:50 000 map, what ground distance does a line 4 cm long represent?
- Why must eastings be given before northings in a grid reference?
- How do the coordinates of point A change when you move it north, and when you move it east?
