Contour Volume and Area

The Grids | Calculate | Contour Vol/Area command computes the volume and area above contour lines, below contour lines, and between contour lines on contour maps. Two contour lines must be defined to calculate the area and volume, otherwise the result is n/a. The computation results are displayed in the grid contour vol/area report. The volume and area results can be saved as an ASCII text file, in Rich Text Format, or can be copied onto the clipboard.

Area results are provided in square units and volume results are provided in cubic units based on the units of the input grid file.

Calculating Volumes and Areas

Click the Grids | Calculate | Contour Vol/Area command or the button to open the Contour Volume and Area dialog.

Specify the minimum and maximum contour lines and contour interval for the sampled contour lines in the Contour Volume and Area dialog.

Input Grid

Specify the source map layer or grid file in Input Grid. Click the current selection and select a map layer from the list. Only map layers created from grid files are included in the Input Grid list. Click Browse to load a grid file with the Open Grid dialog.

The defaults for Minimum Contour, Maximum Contour, and Contour Interval are set on the Levels page in the Properties window for the contour layer.

Minimum Contour

Set the Minimum contour to the value of the first contour line to be included in the calculation. To set a new value, highlight the existing value and type the new value. Press ENTER on the keyboard.

Maximum Contour

Set the Maximum contour to the value of the last contour line you want to be included in the calculation. To set a new value, highlight the existing value and type the new value. Press ENTER on the keyboard.

Contour Interval

The difference between two contour lines is defined as the Contour Interval. The Simple level method is always used to define the spacing between adjacent contours when calculating the volume and area, even if another level method has been set for the contour layer in the plot.

Grid Contour Vol/Area Report

Click OK in the Contour Volume and Area dialog and the results are displayed in the Grid Contour Vol/Area Report. Use File | Save As to save the report, or you can copy the information to the clipboard and paste it into another application.