Draw Contour Lines from a Grid
25 ft × 25 ft practice site, 5-ft grid. Pick the levels to draw; the tool tests every edge, interpolates, and joins the marks cell by cell.
Levels to draw
Line style:
Dash-dot lines follow the practice-solution style. A circled dot is a level that occurs only at one grid point; no line is forced through it. Drawing scale 1 in = 4 ft is only an example; the map is shown to fit the screen.
Interpolation for one level
Check horizontal edges (left to right), then vertical edges (bottom to top).
f = (Zc − Z1)/(Z2 − Z1), divisions = 20f counted from the first point.
Grid elevations (ft)
Rows A (top) to F (bottom), columns 1 to 6, as on the grid paper. Type an elevation in any cell and the map updates. Use the arrow keys, Tab or Enter to move. You can also paste a block of numbers copied from Excel. Changed values are shown in maroon.
Dr. Khondhaker Al Momin · Department of Civil & Environmental Engineering · Rose-Hulman Institute of Technology · momin@rose-hulman.edu