An isoline is a line on a map connecting points of equal value, such as temperature, barometric pressure, or altitude. Isolines must follow certain rules: they connect points of equal value, have gentle curves without sharp corners, form closed curves, never cross each other, and run parallel. The gradient shows how quickly the value changes - steep gradients have isolines close together, while gentle gradients have isolines farther apart. Worksheets can help students practice drawing isolines by highlighting data points, filling gaps, connecting points of equal value, and progressing to the next value.

16. Highlight data points.

17. Fill in gaps in data.

18. Connect the dots.

19. Go on to the next value.

20. Making a Contour Map II

22. Drawing Contour Maps III