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| Brett E. Thompson, Building and Zoning
Administrator |
A common task for surveyors, civil
engineers and GIS professionals is recreating a property boundary
from a plat (a map, drawn to scale, showing the divisions of a piece
of land). Typically, a plat will contain the bearings (direction
expressed in degrees) and perimeter distances (lengths of the edges)
of the property it describes. By changing just a few settings, MicroStation
allows you to quickly and easily recreate a property boundary by
bearing and distance.
First off, you'll want to use a seed file
with the correct working units and coordinates. Assuming the plat
is done in bearings, decimal feet and on a State Plane Coordinate
System (system for specifying positions using plane rectangular
coordinates), we'll use the "2dEnglishMapping.dgn" seed file that
comes with MicroStation. Using this seed file, create a new drawing
and call it "plat.dgn".
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| Use the "2dEnglishMapping.dgn"
seed file that comes with MicroStation. |
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| In the DGN File Settings dialog box,
change the Coordinate Readout settings to ensure you are working
in decimal feet to the nearest hundredth and in bearings to
the nearest second. |
Once you're in the new drawing, you'll
want to change a few settings. Go to the "Settings" menu and select
"Design File". A dialog box will appear, select "Coordinate Readout"
and change the "Coordinates and Angles" settings to those shown
in the graphic below and click <OK> to close the dialog box.
You are setting MicroStation to work in decimal feet to the nearest
hundredth and to work in bearings to the nearest second.
Using whatever attributes are active, you can now begin drawing.
First, go to the "Help" menu and select "Key-in Browser". This will
open a dialog box with a command line for you to enter coordinates
to draw the boundary of your plat. Now, select the "Line" tool.
You will be prompted for a starting point, just enter "XY=1000,1000"
in the command line and hit <Enter>. For the remaining legs
of your plat, you will enter polar coordinates by bearing and distance
using the format "DI=DISTANCE, BEARING". In the command line, enter
the following bearings and distances:
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| Enter "XY=1000,1000" in the
command line and hit <Enter>. |
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| Use the "Measure Element"
tool to check the bearing and distance of each boundary line. |
If necessary, click on "Fit View"
to look at your drawing. The plat boundary should now be displayed.
I always measure the distance from the starting point and ending
point as a closure check. Just use the "Measure Distance" tool,
select "Between Points" and measure, snapping to the endpoints of
the beginning and ending line segments. You can also use the "Measure
Element" tool to check the bearing and distance of each boundary
line.
I hope this article has been of
help to you. I use this process all the time in my own office. Good
luck!
Guest Contributor
Brett Thompson is a graduate of Eastern Illinois
University and serves as GPS/GIS Coordinator for the City of Monticello,
Illinois. He has been a long-time user of MicroStation and has taught
MicroStation at the community college level.
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