Making a Rogaine Map - NSW Rogaining Association

Making a Rogaine Map
Last change date: 12/1/2010
Introduction
Computing and the Global Positioning System (GPS) technology provide today's course setter with the
tools to free them from the restrictions of the pen and paper era. This paper covers ...
• Drawing a map using the OCAD mapping program.
• Field working techniques using a handheld GPS and associated software to make updates and
corrections to the map.
Equipment
• OCAD 8 (or later) software
• Image editing program (Ulead Photo Impact, Adobe Photoshop etc)
• GPS Trackmaker software (free download from http://www.gpstm.com)
• PC running Windows 98 or later. To get acceptable redraw speed you need at least a PIII with
256MB ram and a good video card.
• Scanner (300dpi is desirable)
• Colour printer
• Handheld GPS receiver. For this work I find my Garmin 12 is quite adequate. Later models have
superior sensitivity and other features.
• Download cable for GPS.
• Map board
• Romer
Getting Started
The first step is to install OCAD on your computer. Then, armed with the booklet "Getting Started with
OCAD 8, familiarise yourself with the fundamentals of drawing a map. It will help a lot if you can enlist
the aid of someone who is already familiar with the program.
When you have done this, read on. You will obtain more detail on how to draw a new OCAD map from
an existing hard copy map. This will most likely be a Lands Department topographic map or could be
photogrametry.
Scanning the base map
Divide the map into blocks that border the grid lines. These should be no bigger than 80mm x 80mm (2km
x 2km for a 1:25000 scale or 4km x 4km for a 1:50000scale). If the map does not have a grid, draw
gridlines as accurately as possible from a knowledge of the position of features on the map. Note that the
scale of photogrammetry can change across the map so the grid lines may not be equidistant.
Scan each block with about a 10mm excess on all sides. Scan in clour at 300dpi. Save the file in the JPEG
format.
Creating a new map
Download the files "BlankMap.ocd" & "Symbols.xls". Run OCAD and open the file "BlankMap". Do a
"save as" to a file with a name of your choice. This gives you a set of symbols that have been tailored to a
rogaine map.
Choose "Options/Scales" and set ...
• "Map scale" to the scale of the final printed map.
• Real world coordinates.
• Horizontal offset to the middle of the map.
• Vertical offset to the middle of the map.

• Angle to the grid/magnetic angle.
• Grid distance to the grid line spacing.
Make the two offsets a whole number of thousands of metres otherwise you will get very unfriendly
numbers on your grid scales around the border of the map.
Drawing the map
Choose "Template/Open" and select one of your scanned blocks. If the scale of your base map is a
different to the final scale, set the "Draft scale" to match the final scale. Set the Rotation to the Grid -
magnetic angle. Click OK. The template will appear in the middle of the drawing window. Zoom out so
you can see both the template and the area where it should be. Choose "Template/Adjust (F9)" and using
just one point move the template to approximately the correct position. Now zoom so that the template
and the position it should be are just in the drawing window.
You can now adjust the template accurately using four points set to the outer grid corners of the template.
Zoom in on each corner then zoom out to get best accuracy. OCAD supports nested commands.
You will often find you can't achieve an exact fit. This is because grid squares on the base map are not
square unless you happen to be in the middle of a zone. The OCAD grid is a perfect square. This is one of
the reasons for scanning the map in small sections.. When you come to draw an adjoining section you just
have to tweak the contours and other lines that cross your section borders so they join up.
If you are working from photogrammetry or other source that did not have a grid, you should first draw
onto the map any known features. If there are roads or tracks that show up on the photogrammetry, spend
a few days in the field recording their position using your GPS and draw them onto the map using the
methods described further on. Now check the position of your template against these features. If any are
significantly in error, try readjusting. You may find you have to break the template into smaller areas.
You can now start to draw the map. Some points to consider ...
• Use bezier curves for all curved lines. Once you get the hang of it it is the fastest method and most
definitely produces the best result.
• Don't merge long lines such as contours where they cross your block boundaries. If you happen to
accidentally delete or move one later on it will be more obvious and easier to fix.
OCAD remembers the adjustment of each template so it is easy to reopen the template to check something.
When you "Open" and "Adjust" a template, the position of the template is saved as part of the map.ocd
file. If you "Close" the template you can then "Reopen" it and it will be in its adjusted position.
Doing an "Open" will lose any previous adjustment. OCAD uses absolute addressing to store the location
of the template file so if you pass your work to someone else you need to pass the directory structure.
To draw magnetic north lines on the map, choose "Options/Scales" and change to "Paper coordinates" and
set the "Grid distance" to a value that equals the spacing you want for the north lines. This would typically
be 40mm (1km) on a 1:25000 map. You can now use the grid lines as a guide to accurately place the north
south lines. The spacing should be uniform and set to a value like 1km as these lines provide the user with
a "scale" across the map. Remember that there is no need to have the GIS grid on your final map.
If the position of the lines doesn't fall exactly where you would like them, reduce the value of the "Grid
distance" and use intermediate lines.

Fieldwork
The topographic maps which are used as the base for most rogaine maps will always have errors and
omissions. They can be more than 30 years old. The "cultural" features (roads, buildings, dams etc) are
the most obvious ones you will find to be incorrect. Before you start any serious placement of controls, it
is a good idea to at least get the roads and buildings shown correctly. The tools available to do this are the
traditional mapping board and the GPS.
The Mapping Board. Mapping boards in various forms have been used by orienteering mapers for many
years. Where they use them to draw a complete map in colour, we only need to record corrections to an
existing map. The board I use is a sheet of 16 gauge aluminium, 32cm x 28cm. A simple compass is
screwed to one corner. Print the section of the map where you want to work on an A4 sheet and sticky
tape this to the board. Now cover the map with a sheet of "mylar" (polyester) drafting film. Mylar has two
important properties. It is dimensionally stable and you can draw on it with a hard pencil. Use at least a
4H. Anchor the pencil to the board with a cord. You will lose it in the first hour otherwise. Drill a hole in
a hard rubber eraser and tie this with another cord to your shirt pocket. The other thing you need is a
romer with scales in metres.
Draw crosses on the mylar at the intersection of the grid lines. Rotate the compass housing so that north
on the housing is parallel to the magnetic north lines on the map.
Fix a plain sheet of paper to the other side of the board. Use this to record your notes about things like
GPS waypoints and track logs.
The GPS The most simple use for the GPS is to find out where you are. Read the coordinates and then
use your romer and pencil to put a dot on the mylar on your mapping board. Do this a few times in some
moderately complex terrain and you will soon find out just how inaccurate not only the cultural features
can be but also the contours and watercourses on topographic maps. The good news is that it is easy to do
something about it.
GPS Basics. The first time you use your GPS you need to check some basic settings. Select "Main
Menu / Setup Menu / Navigation" See that ...
1. "Position Format" is "UTM/UPS"
2. "Map Datum" matches your map. For the 1st and 2nd edition NSW maps this is Australian
Geodetic 1966. Later editions use the “Geocentric Datum of Australia 1994”. For more
information on this subject go to “http://www.lands.nsw.gov.au/survey_maps/geodesy/gda” .
3. "Units" are Metric.
The accuracy of a GPS like the Garmin 12 is about 10m horizontally. Later models will give you 3m. The
“GPS” elevation reading will tell you if you are at Penrith or Blackheath or half way in between but that's
about all. Models with barometer altimeters give 5m accuracy. The 10m horizontal accuracy fits in well
with the common rogaining map scale of 1:25000 where 1mm on the map is 25m. The accuracy of your
GPS will be reduced by tree cover and hills that block the view of the satellites. If you know you are going
to be working in a deep valley with tree cover it is worth picking a time to go there when there is a
favourable satellite pattern. These patterns can be obtained from the web. Try
http://www.geocities.com/kiwi_36_nz/alm2pos/alm2pos.htm.
Plotting Point Features by GPS. Point features are easily plotted. Just stand beside them and record a
Way Point on the GPS. You can also read off the coordinates and draw the feature on your map board
using your romer and pencil.
Plotting Linear Features by GPS. Any linear feature such as a road, track or watercourse that you are
able to walk or drive along can be placed on your map. The steps in the process are ...
1. "Walk" the GPS along the feature with "Track Logging" activated.
2. Download the data to your computer.
3. Process the data to create an OCAD image.
4. Draw the feature.

Plotting Area Features by GPS. Area features such as vegetation are handled the same as linear features
by "walking" the boundary of the object.
GPS Track Log settings. For a Garmin 12, select "Map Page / Options / Track Setup". The items here
are ...
1. "Record:" This turns the Track Logging on or off. You should only turn it on when you are ready
to start a walk. There are two good reasons for this, first you don't waste memory space and second
you don't end up with irrelevant clutter in your data. There are two "on" options, "Fill" & "Wrap".
In the "Fill" mode, once the memory fills no more points will be added. In "Wrap", once you have
reached the maximum number of track points the older points will be lost as new points are added.
2. Method: The options here are "Auto" and "Time Interval". Always use "Time Interval". The
value you choose will depend on your anticipated rate of progress along the feature and the to some
extent the twistiness of the feature. A setting of 30 seconds will give you a point every 33m if you
are walking at 4km/h. It also means you can walk for 8 hours before you run out of memory. If
you are driving you will need to reduce the time interval to 10s or less. You will cover the ground
a lot faster but you will also fill your memory faster. Either plan to do the driving in short bursts or
take a laptop computer with you so you can download the data.
3. Mem Used: Keep your eye on this!
4. Clear Log: Remember to do this after each download of data.
Doing a Walk. When you are ready to go, switch on the recording and return to the Map Page. Press
"Mark / Enter" to record a "Waypoint". Note the waypoint number. Write this on the note sheet of your
map board, eg "WP1 - start of Jack's Trail". Start walking. Watch the Map Screen and see that your path
is being recorded. Whenever you come to a significant feature such as a road/watercourse crossing, record
a Way Point and add the details to your paper log. If you stop for more than a few minutes, turn the
recording off.
Processing GPS Data
After returning from the field you now need to transfer the data in your GPS to your OCAD map. OCAD 9
has the ability to do this directly for Garmin's eTrex models. If you don't have one of these you will have
to use the Trackmaker program to read the data from your GPS and save it as an image file which you then
open as a “template” in OCAD. This procedure is described next.
Prepare your GPS to download data. For a Garmin 12, select "Main Menu / Setup Menu / System /
Mode" and change to "Simulator". Select "Main Menu / Setup Menu / Interface" and select
"Garmin/Garmin". Use your special data cable to connect the GPS to an apropriate port on your computer.
Run the program "GPS Trackmaker". Select "Interface / Garmin Interface" or one to match your GPS. On
the "Garmin Interface" dialog that pops up press ..
1. "Product ID". See that this brings up an identification of your GPS.
2. "Request from GPS"
3. "Waypoint" See that the waypoints are transferred.
4. "Tracklogs" See that the tracklogs are transferred.
5. "Exit". The pop up will close and a map is drawn of your tracks and waypoints.
There are a number of adjustments you can make to the view of your data such as showing tracks by
colour, waypoint text, grid and scale. Pan and vary the scale to get the part you want on to the screen.
Keep in mind that when you get to look at the file are creating in OCAD, you are going to have to read
then grid values and the waypoint numbers so don't try to take too big a bite.

The best scale to use will depend on the complexity and density of your data. The aproximate relationship
between Trackmaker scale and OCAD draft scale is shown in the following table.
Trackmaker Scale Resolution change OCAD Draft Scale
1:20 96 > 960 (see note) 16000
1:30 96 > 960 28000
1:50 no 4000
1:75 no 7000
1:100 no 9000
1:150 no 14000
1:300 no 28000
Note: Because of the Draft Scale limitations of OCAD, if you use a scale below 1:50 you must use your
image editor to change the resolution of the file from 96 dpi to 960 dpi.
Do an "Edit / Copy". Run you image editor program and do an "Edit / Paste". See that what you get is
what was on the screen of GPS Trackmaker. Make tone adjustments to sharpen up the image then save the
image as a ".bmp" or JPEG file.
Run OCAD and open your map then ...
1. Zoom in on the area covered by your fieldwork file.
2. Open the file as a template.
3. Set the Draft Scale to the value shown in the table above.
4. Set the Angle to your magnetic deviation. Less blurring seems to occur if you rotate here rather
than in the image editor.
5. Adjust the template using 4 points on the grid crossings. If you have trouble reading the scale bar
on the template, try hiding the symbols that are obscuring the scale while you do the adjustment.
If you have trouble getting the template to line up it is possibly caused by the fact mentioned earlier that
grid squares on the base map aren't square. To get around this try making some adjustments to the
template file with your image editor. First "Expand" the file by 50 pixels all around and then do a
"Transform / Slant". Pull one side up or down by about 1 in 100. If you are smart enough you may be
able to work out which way otherwise a bit of trial and error will soon sort it out.
Using Google Earth Images
If you are lucky enough to be working in an area where Google Earth provides high resolution images
these provide a valuable resource. To line up a saved Google image with your map ...
● Run Trackmaker and open one of your existing “gtm” files. This will get you into the right area on
the planet.
● Delete all the data on the screen.
● Using the pencil tool draw crosses at the four corners of the square kilometre you want view.
● Save as a Google Earth “.klm” file.
● Run Google earth and open the “klm” file.
● After Google zooms in on your selected area, adjust the zoom level so the crosses are just on the
screen.
● Turn off all the layers.
● Select “Options” / “Navigation” and see that “Automatically tilt while zooming” is turned off.
● Don't even think of touching the tilting buttons. If you do, close Google earth and start again.
● Save the image
● Open it as a template in OCAD and adjust it to the grid.

Using SIX
The NSW Lands Department provides a very valuable resource of maps and images available for free. Go
to https://six.maps.nsw.gov.au/wps/portal/ and in the “Have you Seen?” block select “SIX Viewer -
Access to advanced tools and rich data. You will need to install ERmapper plug-in for your browser.
This is a once off operation.
The first warning is this application is going to be slow to use unless you have better than base line
broadband. When you are using it watch both the browser status bar and the SIX Progress bar. After
making a change, don't press on until they both complete.
In the “Take me to:” panel, click on “Suburb” and enter a name. This can be a locality, just about any
name on the map seems to work. In “Results”, click on the most likely looking answer and wait. When it
completes ...
In the “Show Themes:” panel ...
• Move the slider left to Image
• Turn off all the options.
In the “Display Images:” panel ...
• Select East Coast Aerial Photos (Medium-high resolution)
• Select Topographic Maps - whichever series is available in your area.
• Untick anything else that is on.
• Move the Transparency slider left
If the Progress bar gets stuck on zero, try using the “Previous Extent” tool to unstick things.
Click on the “Open toolbox to add extra tools” tool. Select “Copy the current view to the clipboard” tool
and click OK. See that the Copy tool is added to the main toolbar.
Select the “Zoom to an area” tool and zoom in to the area you are using. Work your way in till you reach a
scale of between 5000 & 6000. At this scale, by clicking the “Maximise Map Height” pointer at the
bottom of the map to close the Properties panel you should be able to just get a 1km square block of the
map comfortably on the screen. When you are ready, click the “Copy to clipboard” tool. This open a
small dialog. Click OK and then Close. You must close it before the next copy operation!
Use your image editor to paste then save the clipboard content as “xxyymap.jpg”.
Now move the Transparency slider to the right to display the aerial photography. Don't move the image!
Copy to clipboard and this time save as “xxyyAP.jpg”.
Move the slider back to the left, move the map to line up the next square km and repeat the operations
above.
Do a “Template / Open” of “xxyymap.jpg” and adjust in the same way as used for the base templates.
The template and your map should agree! Now ...
• Close the template
• Rename “xxyymap.jpg”
• Template / Reopen “xxyymap.jpg. OCAD will say it can't find the template. Click on “Browse”
and point to “xxyyAP.jpg”.
You should now have the aerial photo image lined up with the map.

Plotting Complex Features by GPS.
Finding good control sites is partly skill, partly hard work and partly luck. My experience is that some of
the best sites you will stumble across are unusable unless you make corrections to the map. More to come
on this subject ...
Graeme Cooper