How Do I Plot Layers from External Data?

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How Do I Plot Layers from External Data?

Layers can be plotted on a cross-section based on data contained in ASCII text files. The routines for generating these layers are similar to those used in plotting fence diagrams from model stratigraphy. That is the elevation values are interpolated from the source data onto points along the cross-section. The interpolation methodology and parameters and the number of points along the section can be specified.


The source data is contained in two files. The first file, known as the layer file, contains a list of unit names to be assigned to each layer. Note that it is not possible to plot layers that contain more than a single unit name. Layer names are listed one per line. The second file contains the elevation data. This dataset may be entered with a single set of coordinates, elevation, and layer number on each line. The number of layers in this dataset should be one greater than the number of layer names specified in the layers file. Alternatively, data may be entered in a format consistent to that used to define elevation data in the groundwater model FEFLOW.


The following is an example of an Elevation file:







The following zip file contains examples of Layer and Elevation files for two distinct layers for the Springfield dataset. They may not work for a cross-section that you create as the data points need to be on or close to the trace line, but they can be used as an example. An image of the trace line used for this dataset is provided in the zip file. At this time, it is not possible to list multiple layers in one pair of files. (20KB)


The following is an example FEFLOW file format (in this case, wrapped to fit the page):


      1   504252.5289757187  4817258.5318264524      375.9595950000        1        1      375.9595950000

      2   504407.9703819696  4817627.0904202787      373.7507930000        2        1      373.7507930000

      3   504747.4488975980  4817838.6412015725      378.4085080000        3        1      378.4085080000

      4   505146.3297569757  4817868.4693265790      381.5148010000        4        1      381.5148010000


To plot layers, first create a cross-section and then select Plot> External Data> Layers. Select the layers and elevation file names in the Query tab. Note that a summary of the elevation data will be presented on the dialog box. On the Hatch tab, set the hatch styles and colors as desired. To edit the hatch style for a given unit, select the unit from the tabs on the left and then change the hatch style and color.


If the hatch patterns are only showing the hatch background color, reduce the hatch scale. Alternatively, if  only the hatch foreground colors are showing, increase the hatch scale. Hatch scales can be increased globally for all hatch patterns by changing the hatch scale multiplier on the Format tab or by changing the individual hatch pattern scales for each individual unit.


Two things that the user should consider:

1.The layers plot can and will extrapolate beyond the bounds of the data. The cross-sections should be restricted to not extend into an area for which there is no data as this is an undesirable outcome.

2.Layers are restricted to one unit, although more than one layer may share the same unit designation.

3.Every contact elevation surface defined in the elevation data file is expected to contain the same number of points, with the same coordinates in each row. Also, there should be one more contact elevation surface in the elevation data file than the number of layers defined in the layers file.