Drawing codes are sometimes referred to as Control Codes because they control the line work associated with points. They allow you to begin and end lines, close figures, fit a curve to points and more.
To edit the drawing code settings choose Tools | Program Settings | Drawing Codes from the desktop. TPC displays the Drawing Code Settings dialog.
Drawing Codes are predefined codes that tell TPC how to draw the lines associated with a group of points. They add flexibility to Drawing View. With Drawing Codes, you can tell TPC to create a rectangle out of the next three points, omit a line segment or create a figure.
When Drawing View draws a traverse, it uses the Control Point and Side Shot settings to draw and connect the appropriate points in the traverse. The objects created in Drawing View depend on the sequence and type of points in the traverse. The same is true of Drawing Codes. The sequence of codes and points in the traverse determines the lines, arcs and polylines that are drawn in Drawing View.
The use of Drawing Codes is optional. Choose View, Use Drawing Codes to turn them on or off (default = off). When turned on, TPC uses the Control Points settings to draw the corresponding lines, arcs and polylines.
Drawing Codes are free to create drawing objects without any corresponding surveying objects. So if you draw a rectangle from 3 points, you will get a rectangle object in the drawing. TPC will have computed the position for the fourth rectangle corner, but will not create a survey point for it. Or if you fit a curve to a series of points, TPC will draw an arc for the curve but will not create a curved line in the survey.
The rule to remember is that Drawing Codes are for the drawing, not the survey. In contrast, creating the same features on the map with Point Codes and traverses always creates the corresponding survey objects.
Drawing Codes can be used by themselves or in conjunction with other features of TPC.
When importing data from a data collector
If your data collector supports Drawing Codes that allow you to do some level of mapping in the field, turn on Drawing Codes in Drawing View to mimic the map you created on the data collector. You will need to match the Codes in TPC with the codes used in your data collector Drawing Code Settings.
When Plotting Features Like Footings
As a general rule, you create traverses to draw features in a drawing. Letting the traverses do the drawing has may advantages which are lost if you must draw the features yourself like in CAD. One situation where traverses becomes cumbersome is when plotting multiple features like footings. You may not want to create a traverse for each footing. Instead, either using the original traverse or after recalling all the footing shots into a traverse, insert .R3 and .R2 Drawing Commands as needed to have TPC draw all the footing for you.
When Combining Point Codes and Drawing Codes
You may also want to use Drawing Codes is in conjunction with Point Codes. As an example, if you are collecting points for multiple ditch lines, you can use a single Point Code for all ditches and simply insert a Begin Line code into your data each time you start a new ditch or when a ditch line goes under a road or driveway via a culvert. When you sort points into traverse using the Point Code Table, TPC will put all your ditch shots into a single traverse, including their codes.
The following Drawing Codes are currently supported in this version of TPC Desktop.
.BL - begin a line with this point (cancel any incoming line) and draw line to next point, regardless of code
.EL - end the current line with this point. No more lines are drawn until we get another .BL.
.BC - begin a curve (arc) with this point (cancel any incoming line) and draw line to next point, regardless of code
.EC - end the current curve (arc) with this point. No more lines are drawn until we get another .BC.
.BF - begin a figure (polyline) with this point
.EF - end the current figure (polyline) but don’t close back to the initial point
.CF - end the current figure (polyline) and close back to the initial point
.R3 - draw a rectangle (polyline) using the next 3 points
.C3 - draw a curve (arc) using the next 3 points
.R2 - draw a rectangle (polyline) using the next 2 points and width (i.e. .R2 4 creates a rectangle 4 units wide)
.PT point - draw a line to the specified point (i.e. .PT 201 draws a line from 201 to this point)
Drawing commands start with a delimiter (default=period), followed by the command as in .BL = begin line. The delimiter tells TPC this is a drawing command. If you omit the delimiter, TPC will think BL is just part of the point description or note.
The preferred way to use drawing codes is to put them in a Note within a traverse. The Note point type is available from the Traverse View. You designate a Note from the Type menu the same way you would designate a side shot or backsight. A Note point does not reference a survey point, it just holds data at that position in the traverse.
The position of a Note in a traverse is important. Generally, a Note refers to the point immediately preceding or following the Note. Drawing codes that begin a process reference the next point. Drawing codes that end a process, reference the preceding point. In this example, TPC draws a line from point 27 to 28 to 29 then ends the line.
Drawing codes can also be placed in point descriptions. In this example, TPC draws a line from point 27 to 28 to 29 then ends the line.
As a rule, drawing codes should follow any other codes or descriptions for a point. For example, the description “CL .BL” includes the code ‘CL’ and the drawing code ‘.BL’ (Begin Line). The period acts as the delimiter for the drawing code.
27 SS .BL
29 SS .EL
Placing codes in point descriptions extends the use of Drawing Codes to data collectors that do not support notes. However, putting drawing codes in point descriptions has the following drawbacks.
Single codes, like .R3 (3-Point Rectangle) and .C3 (3-Point Curve) operate on a specific group of points after which they are finished and so do not require a corresponding code to end the process.
In this example, TPC draws a rectangle from points 67 to 68 to 69 to a fourth computed rectangle corner then back to 67. The .R3 Code processes the next three points and then is finished.
In this example, TPC draws a curve from points 70 to 72 passing through 71. The .C3 Code processes the next three points and then is finished.
Some codes begin a process and require a second or matching code to end the process. The Begin Line and End Line commands are an example of this.
In this example, TPC begins a line at point 27 and ends it at point 29. Point 30 is then drawn as it would have been if no Drawing Codes were inserted.
Paired codes include Begin/End Line, Begin/End Curve, Begin/End Figure and Begin/Close Figure. In the case of a figure, the Begin Figure can be paired with either an End Figure or Close Figure code.
As a general rule, repeating a beginning code like Begin Line, ends the previous process and starts a new one. The .EL.BL codes between points 29 and 30 in this example could be replaced with just a .BL (Begin Line) code. The .BL code would end the previous .BL process before starting a new one. As a result, the previous process would end with point 29 and the next process would begin with point 30. There would be NO line between points 29 and 30.
TPC includes several drawing codes that create figures. These figures can be closed like a building foundation or open like a road centerline. Figures create polylines in Drawing View, allowing you to modify the properties of all the lines in the figure with one command.
A closed figures draws a polyline segment from the last point in the figure back to the first point in the figure. In this example, TPC creates a closed figure starting with point 81, drawing through point 86 then back to point 81. The drawing command .CF (Close Figure) tells TPC to close the figure back to its starting point.
If point 86 had included the drawing command .EF (End Figure), the figure would have ended at point 86 but would not have closed back to point 81.
The .BC and .EC codes fit a curve to the bracketed points. The curve is drawn an a single ARC object in the drawing using the best-fit radius derived form the bracketed points.
In the following example, a horizontal curve will be drawn from point 81 to point 86 using points 81 to 86 to determine the best-fit radius..
You typically do NOT want to sort points in a traverse when you use Drawing Codes. Drawing Codes rely on the sequence of points to properly draw your survey. Since sorting points within a traverse changes this sequence, you may loose the desired effect of the Drawing Codes.
TPC’s Drawing Codes are flexible enough to be used with any data collector. Some data collectors insert Drawing Codes as notes in which case TPC imports them as notes. Other data collectors insert Drawing Codes into the point descriptors. If your data collector does not support Drawing Codes, you can insert them manually into either the Notes or point descriptors as allowed.
If your data collector does field-to-finish drawing based on the codes, you will want to match TPC’s Drawing Codes to your data collector’s Drawing Codes. Once done, TPC can reproduce the map your data collector drew in the field.
Adding Drawing Codes to a Traverse
Drawing Code Settings