Choose a stretch of coastline or river and try to identify the minimum number of points and their locations that can be used to represent its shape. If you can find the same coastline or river on maps...

Choose a stretch of coastline or river and try to identify the minimum number of points and their locations that can be used to represent its shape. If you can find the same coastline or river on maps of different scales, repeat this exercise with these maps and compare different versions to see the effect of scale.