# Peaks and Depressions Report

The Peaks and Depressions Report is created by clicking the Generate Report button on the General page of the Peaks and Depressions Properties page. It contains the Time Stamp, Data Source, and separate sections with the statistics for Peaks, Depressions, and Individual Peaks. Save or print the report from the File menu commands. See below for the information contained in each section of the report.

### Time Stamp

The date and time the report was created.

### Data Source

The Grid file name provides the path and file name of the data used in gridding.

### Peaks and Depressions Sections

The peaks section and depressions section each provide statistics for the total of all the peaks and/or depressions as long as Show peaks/depressions is checked respectively on the Peaks page or Depressions page in the Properties window.

This list of statistics is calculated for Height (Peaks) and Depth (Depressions), Length, Width, Planar Area, and volume. Three methods are used to determine volumes. Surfer approximates the necessary one-dimensional integrals using three classical numerical integration algorithms: Extended Trapezoidal Rule, Extended Simpson's Rule, and Extended Simpson's 3/8 Rule; see Press et al., 1988, Section [4.1]. The difference in the volume calculations by the three different methods measures the accuracy of the volume calculations. If the three volume calculations are reasonably close together, the true volume is close to these values. If the three values differ somewhat, a new denser grid file should be used before performing the volume calculations again. The net volume can be reported as the average of the three values.

 5%-tile 5 percent of the values are smaller than this number and 95 percent of the values are larger 95%-tile 95 percent of the values are smaller than this number and 5 percent of the values are larger Minimum minimum value Maximum maximum value Mean arithmetic average of the data Median middle data value, 50 percent of the data values are larger than this number and 50 percent of the data are smaller than this number

## Individual Peaks and Depressions Sections

A list of polygons within the peaks or depressions areas provides information about the X and Y coordinates, Elevation which is also the Z coordinate, Height, Length, Width, Orientation, Planar Area, Extended Trapezoidal Rule, Extended Simpson's Rule, and Extended Simpson's 3/8 Rule:are shown. Add labels to the peaks or depressions by clicking the Show label property in the Peaks and/or Depressions pages in the Properties window to cross reference them with the Elevation column in the report.