Volume Estimation

The volume estimation commands include: Volume Total, Volume Polygon, and Get Z Levels.

Volume Total

This command will integrate the z axis data over the interpolated surface to generate a total volume calculation. When the projection is "Mercator", the longitude latitude values are temporarily converted to km from the lower left corner. The surface magnitude of each data point (or subtriangle point) is multiplied by the surface area of the horizontal plane for that triangle. The current interpolation method specified by the Data Interpolation command is used. The resultant total is the total value over the entire surface.

Note that the z axis values are assumed to be input in units/sq km. A constant would have to be applied to the result to adjust for this assumption if other units are used.

There are nominally 3 parameters:

x, y, and z vectors - 3 vectors containing the data.

   OR

xyz matrix - a matrix containing the x, y, and z data as 3 columns.

The output is a matrix with the following elements (assuming the data contour levels of 10, 100, 1000):

Volume_Total(xyz matrix);

Volume Polygon

This command will integrate the z axis data over the interpolated surface to generate a total volume calculation within the specified polygon. If the current projection is "Mercator", the longitude latitude values (an assumption) are temporarily converted to km from the lower left corner. The surface magnitude of each data point (or subtriangle point) is multiplied by the surface area of the horizontal plane for that triangle. The current interpolation method specified by the Data Interpolation command is used. The resultant total is the total value over the entire surface within the polygon.

Note that the z axis values are assumed to be input in units/sq km when the Mercator projection used. A constant would have to be applied to the result to adjust for this assumption if other units are used.

There are 2 or more parameters:

polygon - the n x 2 matrix defining the polygon within which the volume is calculated.

x, y, and z vectors - 3 vectors containing the data.

    OR

xyz matrix - a matrix containing the x, y, and z data as 3 columns.

Volume_Polygon(polygon number,matrix);
Volume_Polygon(polygon number,x vector,y vector,z vector);

Get Z Levels

This command will compute the z axis data values over the interpolated surface at specified locations and return an n x 3 matrix as the result.

This command has 2 parameters:

requested locations - an n x 3 matrix containing the x,y coordinates of the points where the z value is to be computed.

The 3rd column contains the corresponding value of the z value to be substituted if a data point falls outside the area of interpolation.

x, y, and z vectors - 3 vectors containing the data.

    OR

xyz matrix - a matrix containing the x, y, and z data as 3 columns.

matrix = Get_Z_Levels(xyz locations [, xyz data set]);