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FAQ
Got
a question about making an orienteering map? Check
this section first. If you can't find an answer,
post your question to the GAOC net or send it to
Kevin. Scroll
down to see our list of Frequently Asked Questions. |
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| How
do you draw a lake with an island in OCAD?
How do you draw
North lines in OCAD?
Where do I look up
Magnetic North and how do I adjust declination in OCAD?
Where can I get
a pacing ruler? |
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How
do you draw a lake with an island in OCAD?
Use the "cut hole" tool.
Select the lake, select a drawing tool: circle, ellipse,
rectangle .. then select "cut hole". It's just like
drawing, except you are cutting. To fill the lake with
water, use the "bank line" symbol to draw an
outline. When you get the bank in place, then use the
"fill" tool to put water in the lake.
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How
do you draw North lines in OCAD?
1. Select a line object. (bank line, for instance)
2. Select the line drawing tool.
3. Press and hold the <Alt> key to draw an exactly
vertical line.
4. At the top of this vertical line, import the north arrow.
That's File> Import>
and look for "North Arrow.ocd"
5. Click on "Place using the mouse"
and put it at the top of your vertical line.
6. Click in the center of the arrow to move it
around.
7. Drag the little corner box until the north
arrow is just the right size.
That's CORNER, not the sides.
Dragging the sides will squash and stretch the arrow. |
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| Where
do I look up Magnetic North and how do I adjust for
declination in OACA?
Go to:
http://www.ngdc.noaa.gov/cgi-bin/seg/gmag/fldsnth1.pl
Type in the area code of your
mapping project. The value "D" is the magnetic
declination. Make sure you rote your map the right way.
Sam wrote:
The declination is -4 degrees approximately. If we took
a quad map and drew the magnetic north line on it, it
would be slanted to the NW (Counter Clockwise CCW ). All
orienteers used to have to do this at
the start, before the maps were aligned to magnetic
north. If we wanted to rotate that map to align it with
magnetic north, we would rotate clockwise (CW).
You can either rotate the
material you are using as templates before using them in OCAD,
or rotate the OCAD map (under extras?). Don't rotate the
symbols, they should be aligned with magnetic north.
Kevin wrote: The
"Parkland Mapping Manual" recommends drawing a
magnetic north line on your base map. See the instructions on
page eight. From this magnetic north, begin drawing your grid
lines with east-west lines perpendicular to the north line. I
believe this will remove errors due to declination. Using the
"rotate map" function in OCAD is beyond my
comprehension at the moment.
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Where
can I get a pacing ruler?
Click here
for a pacing scale graphic. Adjust the size of this graphic to
match your walking pace at a scale of 1:7,500. Using this
"pacing ruler" in fieldwork will allow you to measure
and draw distances in "paces".
Walk along a linear feature
counting your foot steps. This number is the length of a feature
in "paces" and can be plotted directing on your map
using the ruler. (no math!)
At the fieldwork scale of 1:7,500 a
length of 100 meters is 13.3 millimeters. If your pace for 100
meters is 56 paces, the distance on the ruler from 0 to 56
should be 13.3 millimeters. Do this bit of math one time at home
and you will be spared having to do conversions in the field. |
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Georgia
Orienteering Club - www.gaorienteering.org |
