Producing a Surface or Contour Map from a Regular Array of XYZ Data
When your XYZ data are collected or generated on regular intervals it is possible to produce a grid file that uses your values directly and does not interpolate the values for the grid nodes. You can create a surface data map or contour data map from the data. As long as spacing is uniform across the data extents it does not have to be the same in the X and Y directions.
To produce a surface or contour map from regularly spaced data:
- Create an XYZ data .DAT file from your data. All X values must be in one column, Y values in another column, and Z values in a third column.
- Click the Home | New Graph | Contour/Surface | XY Contour Data Map, Home | New Graph | Contour/Surface | XZ Contour Data Map, or Home | New Graph | Contour/Surface | Surface Data Map command.
- Specify the name of the XYZ data file in the Open Worksheet dialog and click Open.
- In the Property Manager, click on the Gridding tab.
- Set the Number of rows and Number of columns so the spacing of your grid nodes correspond to the spacing of the values in the data.
The calculations for the Number of rows and the Number of columns are:
Number of rows = (Ymax-Ymin)/Yspacing +1
Number of columns = (Xmax-Xmin)/Xspacing +1
You can also produce grid files directly from an evenly spaced array of Z values. When your Z values are organized correctly in an ASCII file, you can add some header information identifying the data as a grid file, specify the limits of the data, and then save the file. The ASCII grid file format is given in Surfer 6 Text Grid Format.