 |
|
|
|
|
Roadway Home
Design Quick Links
NCDOT Quick Links
Internal Use Only
|
|
|
|
|
|
|
|
|
HOME » Questions and Answer |
 |
|
NCDOT Roadway Design Unit: Q&A
Roadway Design Question and Answer Forum
Geopak
Question:
While in the jobls.gpk, I've created an input file with all of L&S's chains using the "Make Input File" command.
When I restore/read the file in Geopak Editor, it stores all the chains except for the -EL-. However, when I am in their COGO,
I can describe chain -EL- and even lay it out using D&C manager. I need to have this chain in my jobrdy.gpk in order to do a layout
offsets of the existing alignment versus the proposed. What is your recommendation?
Answer:
While processing your input, COGO has a problem with spiral LA. This spiral is a Type 4 spiral, which just means that it is a spiral
between two curves. Similar to compound spirals used on ramp alignments. In COGO and for chain -EL-, it can also be stored as a
"SCSCS" series, where the middle "S" (spiral) is the Type 4 spiral.
The generated input commanded appears to be correct. The sharper curve is identified first and its center of curve (CC) is also
identified before the flatter curve. This is consistent with format A4 for Type 4 spirals from the Geopak Reference Manual.
FORMAT A4:
S spi name D2 angle LS length D1 angle C2 pb C1 pa (STA) (CHORD)
I've checked the two center of curve coordinates in the jobls.gpk and they are correct. It may be that this format is obsolete.
Since you already have all the components for -EL- stored, except for SPI LA, then try this old key-in to copy a spiral
from one GPK to another.
FORMAT:
COPY SPIRAL name FROM job#
While in jobrdy.gpk, key-in:
COPY SPIRAL LA FROM JOBLS
Now store chain -EL- like usual.
The copy spiral from one GPK to another command can be saved as part of your COGO input file.
Also as an option, there exists a VBA program that can copy points, curves, spirals, chains, and profiles from one GPK to another.
See Link
|
|
 |
|
|
NC DOT
NC DOH
NC GOV
