Draw

This feature automates the production of a drawing that can contain specific points, lines, arcs and curve fit lines. The draw option also acts as a Cogo function in that it will calculate the PC, PT and radius points of curves and has the ability to calculate points by traversing and intersection.

Prompts

After choosing the Draw command, if a coordinate file is not open, you will be asked to open one.
After opening the coordinate file, you will be asked to select the points you want to map:

Choose initial points for base selection set from coord. file: (Enter when done) [All/Block/Code/Desc/Elev/Pt-group/Limits/Radius/Select]:

Next, you will be asked whether you want to store elevations at calculated PC, PT, and radius points:  When locating items like back of curb you may need to note the beginning and ending of curves.  The points located are never exact as far as the beginning and ending of the curve, but when noted in the mapping routine the application will compute a PC, PT and Radius using the best fit routine and you can choose to store theses points or not.

Note: If Auto Point Plot is ON as specified in the Graphic Options tab of the C&G Options dialog, points will be plotted and lines, arcs and/or curve fit lines are drawn when indicated by Mapping Codes found in the point descriptions.

Mapping Codes Used by the Draw feature

The map codes used by the Draw feature must be placed in the description field for each point in the coordinate file that is to be “Mapped”.
Below is the list of map codes:
BL - Begin Line   
EL - End Line (optional)
CL - Close Figure
PC - Begin Curve (tangent to previous line)
OC - Point on Curve (begin/end non-tangent curve)
PT - End Curve (tangent to next line)
RP - Radius Point
CF - Curve Fit (spline fit to irregular curves)
CC - Compound Curve
RC - Reverse Curve

Mapping Codes can be upper or lower case.  The map code MUST be followed by an asterisk and a line description for the line that is being drawn.  For example: BL*CURB1, where CURB1 is the line description for the line you are beginning. It is OK to have spaces between the code, asterisk and line description, but it is not necessary.

For example:
 
Point ID    Description
5               BL* CURB1 BL*SW1 WV  
6               CURB1
7               SW1 PP
8               PC* CURB1
9               FH
10             PT* CURB1
11            CURB1 SW1
12            OC* SW1
13            SW1
14            SW1
15            SW1
16            OC* SW1
17            CL* SW1
18            BL* CURB1

Important Note: Mapped lines are connected in ascending order by point ID. The point ID’s are always saved in the coordinate file in increasing order. Since the coordinate file is used to perform the Map Drawing and the point ID sequence is produced when the raw data is reduced, it follows that the order of field location of the points will determine point ID sequence order when the lines are mapped.

In the sample sequence above:
Point 5 begins two lines, Curb1 and SW1. Curb1 and SW1 are line descriptions. A line description must be a whole word (no spaces). WV (water valve) is not the beginning of a line because an asterisk does not precede it.

For example:
5       BL*CURB1 BL*SW1 WV   

The Curb1 line will be drawn from point 5 to point 6 to point 8.  This begins a curve tangent to the line from  6 to 8 continuing to point 10.  The curve is tangent to the line from 10 to 11. Since point 18 begins a new Curb1, point 11 is the end of the first Curb1 line (the EL code is not required in order to end a line).

A second line (SW1) will be drawn from 6 to 7 to 11 to 12. At point 12 a non-tangent circular curve begins and continues through points on the curve at 13, 14, and 15. The non-tangent curve ends at point 16 and lines continue from 16 to 17 to 1 (the CL code closes the figure). In creating the non-tangent curve from point 12 through point 16, points 13-15 are used by the Map Draw feature in the calculation of the best fit circular curve.

In addition to the lines drawn, the symbol specified for the WV description in the description table (see CGMngmt) will be placed at point 5 and, at point 7, the symbol specified in the description table for the description PP will be drawn.
As demonstrated in the above example, you may combine multiple codes and line descriptions within a single point description.

For example:
 Point ID                 Description
20         BL*SW1 BL*CURB1 CURB2 EL*CURB3 CL*CURB4

In this example point 20 begins the SW1 line and the CURB1 line. It continues the CURB2 line.  It ends the CURB3 line and it closes the CURB4 line.

The Begin Line Code:

All lines must start with a BL code. No lines will be connected to a point unless a word in the point description matches a BL* line name.

The Close Line Code: The close line code (CL) causes the Draw Map feature to connect the CL point to the BL point. You can also use the CL command to traverse. Thus you may place dimensions after a CL command.
For example:
Point ID    Description
   20        *BL*BLD1
   21        CL*BLD1+10.1+10.2-20.3+50.6 EL*SW1

Note: The FC-48 data collector does not allow ‘+’ characters in description field. Because of this, the ‘/’ character can be used instead of the ‘+’ character in all the CL examples.
In the above example a line will be drawn from point 20 to point 21. The following points will then be calculated through a traverse sequence (assume the next point available is 100):

Occupied Pt       BS Pt     Angle     Distance      New Point
21                        20          90          10.1             100
100                      21          90          10.2             101
101                    100        270          20.3             102
102                    101          90          50.6             103

Point 103 will then be connected to point 20 to close the BLD1 line. Please note that point 21 is also the end of the SW1 line.
In a CL mapping code sequence, a negative dimension turns -90 degrees from the back azimuth and a positive dimension turns +90 degrees from the back azimuth. Both the ‘+’ and ‘-’ symbols are required but, as noted above, the ‘/’ symbol can be substituted for the ‘+’ where necessary.
This same figure could also be drawn using the following sequence:

Point ID        Description
        20         BL*BLD1
        21         CL*BLD1+10.1+10.2-20.3+

Note that the closing distance was not included in the description sequence. See the following examples.
If you have located two corners of a rectangle, you may use the following short cut:

Point ID        Description
         20        BL*BLD1
         21        CL*BLD1+50.6+

In the above example a line will be drawn from point 20 to point 21. The following points will then be calculated through a traverse sequence (assume the next point available is 100):

Occupied Pt    BS Pt    Angle    Distance    New Point
        21              20         90         50.6          100

Point 101 will be calculated by a bearing-bearing intersection. Then point 101 will be connected to point 20. The first ‘+’ sign determines the direction used to calculate point 100. The description ending in a ‘+’ sign has the same effect as ending in a ‘-’ sign: if there is no dimension after the last ‘+’ or ‘-’ sign, the last point will be calculated by a bearing-bearing intersect.
If you have located three corners of a rectangle, you may use the following short cut to define the lines to be drawn:

Point ID        Description
20                 BL*BLD1
21                 BLD1
22                 CL*BLD1+
 
In the above example lines will be drawn from point 20 to 21 to 22. The missing corner will be calculated using a bearing-bearing intersect and stored. As noted earlier, ending in a ‘-’ sign instead of a ‘+’ sign has the same end result.

Curve Codes

Anytime a circular curve is encountered, 3 new points may be calculated and stored in the coordinate file. These points are the PC, PT and radius point of the curve. It is necessary to calculate these points during automated mapping since the field points are only approximations of a perfect curve. They will automatically be assigned point numbers (regardless of the Auto Point Numbering setting). The points calculated during automated mapping of curves will begin with the coordinate files current high point number plus 1.
If the beginning of a line is also the beginning of a curve, one of the following formats must be used:

          Point ID        Description
             10              BL*SW1 CF*SW1 (begin a curve-fit line)
     or    10              BL*SW1 OC*SW1 (begin a non-tangent circular curve)
     or    10              BL*SW1 PC*SW1  (begin a tangent circular curve)

Once a curve has begun, all matching line descriptions will be considered points on the curve until the curve is ended.  A curve is ended with either a PT*, OC*, or CF* code.
For Example:

    Point ID    Correct Sequence          Incorrect Sequence
    10              OC*SW1 (Begin SW1)                           
    11              SW1                                OC*SW1 (will end SW1)
    12              SW1                                OC*SW1 (will end SW1)
    13              SW1                                OC*SW1 (will end SW1)
    14              OC*SW1 (End SW1)

The first OC begins the curve. The next OC ends the curve. All the points between them are on the curve. The same is true for curve fit  (CF*).
If a curve is either tangent (in), tangent (out) or tangent (in) & tangent (out), you only need two points to define the curve:

Point ID     Sample 1         Sample 2          Sample 3
    10           PC*CURB1    PC*CURB1    OC*CURB1
    11           PT*CURB1    OC*CURB1    PT*CURB1
Otherwise you will need at least three points on a curve:

Point ID           Description
        12             CF*CURB1
        13             CURB1
        14             CF*CURB1

The RP Mapping Code

If you use the RP code (radius point), it will be used regardless of the number of points on the curve. The radius will be calculated by averaging all the distances from the radius point to the points on the curve.
Best Fit Circular Curve Calculations
If you have three or more points on a non-tangent curve, the best-fit curve solution is used to find the radius point.
If you have three or more points on a tangent curve (either tangent in, tangent out, or tangent in and out), the best-fit curve solution is used to determine an approximate radius and radius point. A dummy point is then calculated on the curve and a curve is drawn that goes through the dummy point and meets the tangent criteria (the PC and PT points are shifted up/down the tangent lines as necessary). If only three points are located, PC, POC and PT, the curve will always go through the POC point.
If you have only two points (PC and PT) on a tangent curve, the tangent lines from the PC and PT will be intersected to find the PI of the curve. The distance from the PI to the PC and the distance from the PI to the PT will be averaged to obtain a tangent distance. A new PC and PT point will be calculated on the tangent line and the radius point will be calculated based on the tangent and central angle.

Non-Circular Curves

You may use the CF* code for a non-circular curve fit (splines). The CF code will start a curve fit line. The curve will continue until a second CF* code is encountered, example:

Point ID            Description
    11                  CF*SW1
    12                  SW1
    13                  SW1
    14                  CF*SW1

Only use CF to start or end a curve. Notice points 12 and 13 do not have automated mapping codes.
A smooth curve will be drawn through points 11, 12, 13 and 14. No new coordinate points are generated with the CF code.

Layers and linetypes for mapped lines and curves

The description table determines the layer in which a mapped line will be drawn. For mapped lines and curves, only the description and layer fields in the description table are used.   However, if the default layer is not set, no description table lookup is performed and the line is drawn on the current layer. 
For example, assume that the default layer has been set and that the description table contains the following entry:

Desc. No.     Description        Layer Name
    5               CURB                 Road

Since layer “Road” is specified for description “Curb”, all lines with descriptions “Curb” will be placed in layer “Road”. Numbers are not used in the comparisons: Curb1, Curb2, Curb10, etc. are considered a match for the description “Curb” and will therefore be placed in layer “Road”.
If a matching description is not found in the description table, the line is drawn on the default layer (as set in the Graphic Options tab of the C&G Options dialog box).

Calculated Points

All coordinate points that are automatically calculated and stored during automated mapping are given a MP point code.
 
Note: Even though the point description field can contain Mapping Codes, the point code found in C&G coordinate files is separate and distinct from the point description field. All points already having an MP Code are ignored by automated mapping.  This avoids re-mapping points that were generated during automated mapping and thus were not points actually located in the field.

Important Note: Consider the MP point code as a reserved code and do not use     it for field data collection.
The description (e.g., CURB) used for calculated points is the same as the line description of the points the calculated point is associated with and reflects the type of calculated point that it is.

For Example:
Assuming the line description for the following points is “CURB1” and the points are the PC, PT and radius point of a curve, then the line descriptions will be:

New Point ID        Point Code          Description
   100                     MP                      PC CURB1
   101                     MP                      RAD.PT CURB1
   102                     MP                     PT CURB1

Plotting of Points

If Auto Plot Points is “On”, all the selected points in the coordinate file will be plotted on the screen during the mapping process. If a default layer is set, Each point will  be drawn on the layer specified in the description table.  The points labels will be configured as specified in the description table. Any point that does not have a description match in the description table will either be drawn on the default layer.

Pulldown Menu Location: CG-Survey >Auto Map>Draw
Keyboard Command: MAP, CG_MAP_DRAW
Prerequiste:  Coordinate file