Calculates the difference between the value of a quantity in one point and the value of the same quantity in another point across a basin.



Inputs

  1. The !GridCoverage of the drainage directions, obtained with [Markoutlets]);
  2. The !Gridcoverage containing the date on which estimating the difference;
  3. The !Gridcoverage containing the quantity of which calculating the difference;


Output

  1. The !GridCoverage with the differences;


Notes

The points in which calculating the difference are individuated by an opportune matrix. Typically this matrix could contain the values of the Strahler numbers of a net, i.e. the network pixels are labeled by the stream number and the same stream contains a group of subsequent pixel. The points chosen for the calculation of the difference are the first and the last of any stream, i.e. those in which the numeration changes.

If the matrix of the quantity to calculate is that of elevations, then, again in the case shown, netdiff calculates the elevation difference along a Strahler branch. If instead of the file containing the Strahler numeration the matrix of the magnitude is used, the variation of a quantity in a link is measured.



References