1. Rules for Drawing Isopleths

2. 36 39 3540 Rules for Drawing Isopleths Isopleths should be as smooth as possible, interpolating as you go. That is, the 35 isopleth would be close to a value of 36, yet far away from a value of 39. Always draw an isopleth so that values greater than the value being drawn are consistently on one side of the isopleth and lower values on the other side.

3. Rules for Drawing Isopleths Isopelths are drawn at regular intervals, based from an “indexing value” The value varies from map to map; the homework includes the values you should use. Isopleths should be clearly labeled. Isopleths cannot be skipped if there values fall within the range on the map. They must also appear in sequence. Example: Must be a 60 degree isotherm between the 50 and 70 degree isotherms. Adjacent isopelths tend to look alike. USE A PENCIL!

4. 75 70 73 77 68 72 71 = NO! Rules for Drawing Isopleths Isopleths never stop or end within a data field, and they never fork, touch, or cross one another. Continue drawing an isopleth until it reaches the boundary of the plotted data or “closes” to form a loop by making way to its starting point.

5. 75 70 73 77 68 72 69 75 = YES! Rules for Drawing Isopleths Isopleths never stop or end within a data field, and they never fork, touch, or cross one another. Continue drawing an isopleth until it reaches the boundary of the plotted data or “closes” to form a loop by making way to its starting point. 75