Polygon computations (Kingdom only)

For polygons on an editable polygon layer, you have the option to perform a series of computations on grid data based on the bounds of the selected polygon or polygons. After you select one or more polygons using the data selection tools, you can select the Polygon Compute option from the list at the bottom of the Selected Features window. Spatial Explorer saves the computation results with the editable polygon layer and displays them in the Details Panel.

You can also perform polygon computes on drainage bubble and buffer layers. Spatial Explorer saves the computation results to a well zone since each drainage bubble or buffer layer is tied to a borehole. The computation results appear in the Details Panel.

You can perform the following computations:

Computation Definition

Arithmetic mean

The arithmetic mean, or average, of grid values.

Arithmetic mean standard deviation

Standard deviation of the arithmetic mean.

Geometric mean

Indicates the central tendency or typical value of a set of numbers by using the product of their values rather than the sum.

Geometric mean standard deviation

Standard deviation of the geometric mean.

Harmonic mean

The reciprocal of the arithmetic mean of the reciprocals.

Harmonic mean standard deviation.

Standard deviation of the harmonic mean.

Maximum

Maximum grid value.

Minimum

Minimum grid value.

Mode

The value that appears most often in the data set

Percentile = n

The value of the grid at the selected percentile. The 10th and 90th percentiles are selected by default. To change this, enter a number between 0 and 100.

Range

The range of grid values.

Variance

The variance of grid values, where the variance is the average of the squared difference from the mean.

Volume

Calculates an average volume based on the length, width, and average thickness of the grid within the bounds of the selected polygon(s).

You can perform any or all of these computations based on a grid you select and the bounds of the polygon or polygons you select. The computations are performed on the grid data contained within the bounds of the selected polygon or polygons. To perform volume computations, the entirety of the selected polygon or polygons must be within the bounds of the selected grid.

For editable polygons, the results of any computations you perform are saved with the editable polygon layer. If the polygon is associated with a well (for example, drainage bubbles and buffer layers), the data is saved to zones. To preserve the computation results, you can also save the polygon as a shape file. This is a useful way to preserve the computed data in case you need to delete the editable polygon layer. In fact, if you attempt to delete an editable polygon layer containing computational data, Spatial Explorer prompts you to save the layer as a shape file.

  1. Select the data layer with the editable polygons, drainage bubbles, or buffer layers you want to use for data selection in the Layers list and click .
  2. Choose the selection tool you want to use from the map toolbar and select the polygon(s) you want to use to select grid data.
  3. The Details Panel opens.
  4. Select Polygon Compute from the Save as list and then click . The Polygon Compute window opens.
  5. In the Selected Grid list, select the grid containing the data you want to use for computations.
  6. If the polygon or polygons you selected are tied to one or more wells (for example, drainage bubbles and buffer layers), select the zone where you want to save the results of the computations.
  7. Select the computations you want to perform, or click Select All to select all the available computations.
  8. If you want, change the default name of the attributes that will be saved, or accept the default names.
  9. If you select the Volume calculation, you have the option to treat negative values as 0 and you can select the units to use (for example, acres, hectares, square feet, etc.).
  10. Click Compute.The computations are now saved with the editable polygon layer or to the selected zone (well data is saved only to zones).
  11. Click Close.

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