The Spacing datasheet window
The spacing window (see Figure 2 below) displays spacing data in two possible
ways:
- Discontinuity spacings : in this case, the spacing data represent the spacing
distances between two successive discontinuities of a scanline:

- Intersection distancies : in this case, the spacing data represent the
cumulated distance of the intersections between the discontinuities and the
scanline:

The intersection distances must be in an incrising order. The
0 value is not allowed as a discontinuity spacing or as an intersection
distance.
The spacing window is composed of the following elements:
- A Comment / title textbox : this text is used in the title of an
histogram/variogram created whith this spacing datasheet.
- A Family name textbox : this text is used as the first part of the
subtitle of an histogram/variogram.
- A Location textbox : this text is used as the second part of the
subtitle of an histogram/variogram.
- A Dip orientations group : these textboxes are for the input of
the dip direction/dip angle of the cliff wall, the discontinuity set and the
scanline. The two latter are used (if not left blank) to calculate the theta
angle displayed between the two data grids.
- A Type of data group, used to select between Discontinuity spacings
and Intersection distances (see above).
- A Discontinuity data group : this group contains two grids. The
one on the left is used for the input of the spacing data (apparent spacings).
The other on the right displays the corrected data (true spacings, using the
theta angle). The theta angle (= angle between the perpendicular to the discontinuity
set and the scanline) is automatically calculated or may be entered manually
if the dip direction/dip angle of the discontinuity set and the scanline are
not specified.
Three different operations are possible using the buttons contained in the
Discontinuity data group:
- Convert : this computes the true spacings using the measured data and the
theta angle.
- Variogram : this computes and displays a variogram of the true spacings
(corrected data)
- Histogram : this computes and displays an histogram of the true spacings

Figure 2 : Spacing datasheet of MatterCliff with
data from Priest (1993)