Contour Interval????/?
What is a counter invertal? , how I can use it in sketching / plotting counters or in topographic surveys?
I have a problem horizontal scale is 1:125 with a contour interval of 20 meters, while the index contours is 1522.82-1441.32, how can I determine the intermediate contours?
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Interpolate linearly. Place a scale (ruler) perpendicular to the two contours of 1522.82 and 1441.32 and mark a point at the distances corresponding to the contours of 1460, 1480, 1500, and 1520. Use the following "factor" as the fractional amount of the distance between the two contours. Move the scale and do it again. Then connect the dots. For example, if you measured 25 cm between the two outer contours, place a dot at 5.73cm, 11.87cm, 11.87cm, and so on. Each time you move the scale, the distance may be different, so you'll have to recalculate the points. (e.g. for 20cm, the 1460 point would be 20cm x .2292 = 4.58cm.) If it's close to 25cm, you can skew the scale a little so that it spans exactly 25cm, then use the values in the table:
Contour - Factor - 10cm - 25cm
1522.82 - 1.0000 - 10.00 - 25.00
1520.00 - 0.9654 - 9.65 - 24.13
1500.00 - 0.7200 - 7.20 - 18.00
1480.00 - 0.4746 - 4.75 - 11.87
1460.00 - 0.2292 - 2.29 - 5.73
1441.32 - 0.0000 - 0.00 - 0.00