Create a map of Peaks & Depressions in Surfer

It is now possible to create a map of peaks and depressions from a grid file in Surfer. This new layer type identifies the peaks and depressions in the grid by drawing a polygon around these areas. This is a closed contour where drainage flows away from it (peak) or into it (depression). 
The Peaks and Depressions layer is similar to the current hachuring of closed contours, but with a few important differences:
  1. The peaks and depressions layer only enclose the base of a peak or depression, not all closed contours within each peak or depression. If you choose to hachure closed contours, then all closed contours are hachured.
  2. You can choose to display all local peaks and depressions, or just the highest peak or lowest depression area within the grid file. 
  3. You can hachure and color peaks differently from depressions.
  4. You can mark the maxima or minima location within each peak or depression area with a symbol, and label it with the Z value.
  5. You can generate reports of the peak or depression areas including width, length, volume, area and orientation of each area.

 

To create the Peaks and Depressions layer:

  1. Click Home | New Map | Specialty | Peaks and Depressions
  2. In the Open Grids dialog, choose you grid file and click Open. The Peaks and Depressions Layer is created.
  3. Click the Peaks and Depressions layer in the Contents window to select it.
  4. In the Properties window, the General tab, Peaks tab and Depressions tab control the properties for the map layer.
  5. Click the General tab:
    • Grid file: Specifies the grid file (with options to change the file or display grid information
    • Display data: Choose to display either all the local peaks/depressions or just the maximum/minimum peak/depression
    • Report: Create a report of statistics of the peak and depression polygon areas.
      View of the General Properties for a Peaks and Depressions layer in Surfer.
  6. Click the Peaks tab.
    • Show peaks: Check/uncheck to show/hide peaks
    • Line properties: Set the line properties for the Peaks polygons
    • Fill properties: Set the fill properties for the Peaks polygons
    • Maximum: Choose to put a marker symbol and/or label at the maximum point in each peak polygon (the label shows the Z value), set the marker symbol and label formatting properties
    • Hachures: Choose to show hachures on the line and set hachure line direction & properties. You can set it to show only the areas (no symbol marker or label), or just show the symbol marker/label with no polygon areasView of the Peaks Properties for a Peaks and Depressions layer in Surfer.
  7. Click the Depressions tab.
    • Show depressions: Check/uncheck to show/hide Depressions
    • Line properties: Set the line properties for the Depressions polygons
    • Fill properties: Set the fill properties for the Depressions polygons
    • Minimum: Choose to put a marker symbol and/or label at the maximum point in each depression polygon (the label shows the Z value), set the marker symbol and label formatting properties
    • Hachures: Choose to show hachures on the line and set hachure line direction & properties. You can set it to show only the areas (no symbol marker or label), or just show the symbol marker/label with no polygon areas

 

  • For the Peaks and Depressions Report (General tab):
    1. Click Generate Report. An Options dialog allows you to adjust the Z scale factor (e.g. if your Z is in different units than XY): 
    2. Click OK and a report is created with statistics for all peak and all depression polygons that are visible on the screen.
    3. The combined peak and combineddepression statistics are followed by sections for each individual peak and each depression polygon. It shows the grid file, followed by the 4 possible sections:
      • Peaks. This is the general data for all Peak polygons. It shows the number of polygons and then the statistics for them all together:
      • Depressions. This is the general data for all Depressions polygons. It shows the number of polygons and then the statistics for them all together:
      • Individual Peaks. Shows the statistics for each individual Peak polygons.
      • Individual Depressions. Shows the statistics for each individual Depressions polygons.
        View of the Peaks and Depressions Report in Surfer.
    4. Note that peaks have Height and depressions have Depth. This is the height of the depression or peak, the difference in Z values of the outer edge of the polygon to the minima or maxima point.

 

Updated October 27, 2021

 

Was this article helpful?
1 out of 1 found this helpful

Comments

0 comments

Please sign in to leave a comment.