Lines - Changing Codes

When surveying linear features, it is often required that the same point is used for more than one feature.  This can happen where a fence changes into a wall or where a gate is in the middle of a fence.

The New Code dimension, normally N=, can be used to change the feature code at the current point.  The point will be used twice, to end the current feature and to start a new one with the code taken from the dimension value.  The point will only be displayed once along with its annotation.

The Seg Code dimension, normally M=, can be used to change the feature code for the line segment that follows the current point.  Just the one segment will use the new code and subsequent segments will revert to using the normal point code. This dimension only works where the segment code is either another line or a 2-point symbol.

New Code Dimension	Segment Code Dimension	Segment Code Dimension

The first of the examples above shows the use of a new code dimension where a hedge finishes and a fence starts at the same point.  The second shows the use of the segment code dimension where a single segment of the hedge is displayed as a fence.  It also illustrates how the curve fitting is carried through the feature regardless of the change in code. The third shows the use of the segment code dimension where a single segment of the hedge is displayed as a gate.

It is possible to include either of these dimensions in the point code by identifying separator characters for such items.  These are defined in the Dimension Strings Dialog. The New Code Separator field defines a character that is used to indicate the presence of a new code dimension.  In the first example above, with the new code separator being a slash, the point code should be HE01/FE01.  The Seg Code Separator field defines a character that is used to indicate the presence of a segment code dimension. In the second and third examples above, with the segment code separator being a colon, the point codes should be HE01:FE or HE01:GT.

If you do not wish to use the code separators, ensure that these fields remain blank. Alternatively, you will need to ensure that the character you have chosen is not alphanumeric and easy access from your total station or data logger keyboard. You should also ensure that you do not use the same characters as those you have specified to indicate a comma code.  Also, you cannot use both separators on the same code.