This command creates Carlson points along a centerline either at
picked points, point numbers, entered individual station and offset
or at station interval with offset, in all cases using the
elevations calculated from the template design files. The first
offset prompt is for the location of the point. The second offset
prompt is for what elevation to use. For staking template points
(e.g. edge of pavement) you usually enter the same offset for the
position and for the elevation. But if you are staking back of
curb, which might be at offset 14.5, you might enter 16.5 for the
position (to stake 2' back of curb) and 14.5 for the vertical
elevation (to use the elevation of back of curb itself). The points
are stored in a coordinate (.CRD) file. The station and offset of
the point is stored in the point descriptions. If the points method
is used and existing Carlson points are selected by number, range
or "point group", then new points at the same position are created
with interpolated elevations and new descriptions. The command
starts with the dialog shown below. The required design files
include the template file, the profile which defines the vertical
alignment, the centerline file which contains the horizontal
alignment and the coordinate file for storing the resulting points.
All these design files must be created before running this command.
To specify a design file, pick on the type of file button.
The optional files include an existing section file for calculating
the cut and fill slopes, a rock section file for special cut slopes
in rock, a template transition file and a super elevation file. For
example, if an existing section is specified, template points can
be calculated further from the centerline, all the way from the
shoulder out to the "catch" or tie point in cut and fill.
If you choose the Station/Offset method, you can specify whether
to create points at a station interval. Otherwise the program
prompts for each station at which to create points. If the
Station/Offset method is used, you will be prompted whether to
calculate points on the left, right or both sides of the centerline
and whether to offset the calculated elevation by a delta Z amount.
If you choose the Points method, you can pick points on the screen
(using snaps on entities if desired) or you can specify point
numbers individually, by selection set, by range or by point group.
You can also select whether to calculate elevations from the
template surface or from a subgrade and you can add a description
prefix to all descriptions.
A classic application of this routine would be for road staking
such as setting back of curb points. Many survey companies prefer
to stakeout roads by pre-calculated point numbers rather than
calculating from road design files in the field to stakeout road
offsets. So if the goal was, for example, to stake 2 feet behind
the back of curb, but use the elevation of the top of curb, and the
shoulder rose at 4% behind the curb, then the vertical difference
to the top of curb would be -2*0.04=-0.08. The program will
calculate this automatically by the method of asking for the
distinct offset to use for the elevation. Obviously, if you want to
stake to the exact surface elevation at the offset specified, then
enter the same offset for both position and elevation. The
prompting for this back of curb example is shown below.
Template Points dialog: Specify the required files and
optional files.
Additional Options dialog: Choose Station/Offset or Points
method, as shown below:
Offset for X,Y position: 16.5 In this case, this
is the pavement width (12.5) plus curb width (2) plus back-of-curb
offset (2). The northing and easting for the points will be
calculated with this offset.
Offset for elevation <16.5>: 14.5 The
elevations for the points will be calculated at this offset (back
of curb in this example).
Apply offset to left, right or both sides
(Left/Right/<Both>)? press Enter Note that if you
want to have the points number sequentially on the left side and
sequentially on the right, then do L for left first and R for right
second. If you answer "Both" then the numbering will go
sequentially left to right on each station (see below).
Offset to process (Enter to End): press Enter Or,
enter an offset to calculate another X,Y position, or the same X,Y
position but on a different side of the road if doing L and R
distinctly.
Pulldown Menu Location:
Roads
Keyboard Command: tplpts
Prerequisite: A template file, profile file and centerline
file