So you want to make an orienteering map. Here is a compendium of my latest knowledge and advice; it is not a guaranteed process and may have glitches! Possible procedures for making small maps are changing rapidly. U.S. Geological Survey topographic maps and aerial photos are now available free on the World-Wide Web. The accuracy of inexpensive GPS units has just been increased to about 10 meters. A demo version of OCAD 7, the orienteering map-drafting program, is also free from the web. With these tools and with the rather tedious and time-consuming task of field checking, you can produce either a simple black-only "schoolyard" map or a color orienteering map for small events.
The mapping process requires four steps: base map preparation, field checking, drafting, and reproduction.
Choosing the method of reproduction of the map is the first step. For schools simple black-only maps are best because they can be cheaply reproduced by photocopying. For local orienteering events, maps can be individually printed on inkjet printers (at least 600 dpi resolution) or can be color photocopied from an inkjet original.
The overall process described here does not cover the following situations:
The latter two cases require base maps made by orienteering interpretation of low-level aerial photographs.
The programs discussed here require a PC running Windows-95 or later.
A scanner is required in order to scan your field-checking into OCAD.
A printer is required, preferably with 600 or 720 dpi resolution.
Download OCAD from http://www.ocad.com. OCAD is the program used internationally for drafting orienteering maps. Three free versions are available: OCAD8 Demo, which is limited to 1000 objects, OCAD7 Demo, which is limited to 2000 objects, and OCAD6, which is not limited. The full version of OCAD costs about $400. For beginners I recommend the OCAD7 Demo, though it lacks course setting capabilities. It is suitable for most simple maps. Use Extras-Optimize/Repair to eliminate deleted objects, which otherwise still count. Another workaround for the object limit is to split the map in half, print them separately, and paste them together for copying.
If you do not have graphics software, download IrfanView from http://www.irfanview.com. IrfanView is a nice, simple, free graphics program for changing image formats, cropping, and capturing from the screen.
For color orienteering maps, download the new International Specification for Orienteering Maps (ISOM2000) from the International Orienteering Federation. This is a 1.8Mb PDF file. All current versions of OCAD come with this symbol set.
Download my symbols.zip and unzip it to three OCAD7 "maps": bwsym.ocd, iofsym.ocd, and fieldsym.ocd. The bwsym.ocd file contains a symbol set for black-only maps, while iofsym.ocd contains the ISOM2000 international symbol set . Both include my additions for text symbols and other items such as a scale bar. Fieldsym.ocd shows the symbols I use for field checking (see below).
A GPS unit is useful but not necessary. I have used a Garmin 12 with Waypoint+ software (free from http://www.tapr.org/~kh2z/Waypoint/). Now I use a Garmin eTrex with GPS Utility in the registered version ($40).
For field checking you will need the following:
The overall process of computer-drafting or "OCADing" a map is technically a raster to vector conversion. Topo maps, photos, scanned field checking, and BMP images are all raster images, which are defined by row after row of pixels in which each pixel has a color value. An OCAD map (and maps from other mapping programs such as Autocad or ArcInfo, and Postscript images) are vector maps in which each feature is described separately as a point, a line, or the bounds of an area. Vector images are both more accurate and smaller (file size) than raster images. The conversion from raster to vector form is done much better by the human brain than by any computer program. So OCADing a map involves drawing (with a mouse or pen pointer) lines over a raster image called a template.
Play around with OCAD to learn its techniques and features. Read the online help thoroughly. This document is not a manual for OCAD.
The purpose of a base map is to have as many "fixed points" and fixed linear features as possible on the map before starting field checking. In addition, the base map includes the best available knowledge of all other relevant features like streams and contours. Producing a base map in the U.S. has just become rather easy, thanks to the availability of both topographic maps and aerial photos on the USGS Terraserver web site, hosted by Microsoft (another instance of Microsoft's monopoly power). Improvement in accuracy of GPS units this year has made them useful for orienteering mapping.
WARNING. Aerial photos are only available for about a third of the country so far. In New Hampshire, coverage seems patchy. If there is no photo for your area, you'll have to ignore all the stuff below about using it. Supposedly the country will have full coverage in a year or two.
Go to http://terraserver.homeadvisor.msn.com/, type the name of the nearest town to your map (do NOT type a state abbreviation) and search. Select the desired town/state and choose either the topographic map or the photo (note the dates!). Click on the map to zoom in (or on the minus button to zoom out). Click on L to cover the biggest area. Move around with the green arrows. Zoom to the 2 meter resolution as shown by the red vertical line. You will need to download or screen capture the image of the area you are interested in. Click on the Photo bar to switch to the photo and download or capture it too (you may need to move around a little). I have not yet checked to see if downloading gives a better image than capturing; capturing seems pretty good and is much faster.
Downloaded images will be in JPG format which OCAD cannot use. You will need a graphics converter program to change the images to BMP format and, optionally, crop them. I use IrfanView to capture the images I want from Terraserver (Options-Capture-ClientArea), crop them, and save as BMP files. IMPORTANT - MAKE SURE YOU INCLUDE THE BAR SCALE AT THE BOTTOM OF THE IMAGE IN AT LEAST ONE PHOTO AND ONE TOPO. You can also change the brightness and contrast of the image using IrfanView, but I don't currently think this is necessary.
Many schools have engineering maps of the school area available. Unfortunately they are usually very large and awkward to work with. Get it photo-reduced before scanning if possible. Or you can scan it in pieces and put them together with a computer graphics program (but not IrfanView).
A GPS unit such as a Garmin 12 can assist the base map process. GPS output is definitely more accurate than a USGS map and may be more accurate than an engineering map. So the GPS should be the primary source of data. The GPS must be set to read out in UTM values. The datum used does not matter (WGS84 default).The following procedure may have to be modified for different equipment.
Examine the USGS map and/or any other available map and select a number of point features to visit with the GPS unit. These might be main building corners, street crossings, power line or stream crossings of roads. USGS vegetation (green) corners are not useful at this stage. Take the GPS to these points and get the most accurate UTM readings possible (use built-in averaging or repeated readings at different times). An active external antenna may increase accuracy under vegetation. You can save these as waypoints on most GPS units, but you can also just write down a description and UTM values for each point. You can also get readings at fixed points that are not on the map; just make sure you note what they are.
You can plot the points by hand on graph paper and scan them to make an OCAD template. If you have a Garmin you can download and plot the points to the screen using Waypoint+, then use IrfanView to capture the screen image and save it as a BMP file for a template. Waypoint+ draws the waypoints oriented to True North. Print a list of the waypoints from Waypoint+ if you don't have a written list.
You can also try downloading, displaying, and capturing the stored route, but it may not be very accurate.
Open OCAD 7 and load BWSYM.OCD or IOFSYM.OCD for a black or a color map. Then change the map grid from the default millimeters to a UTM grid. Set Options-Scale-MapScale to the scale of the final map. Then choose RealWorldCoordinates and set the horizontal and vertical offset values. The values are chosen as three digit numbers that are the last three digits of a UTM value somewhere on the map rounded to the nearest 100 (meters). For instance, for a UTM point of 358831/4796264, set horizontal to 800 and vertical to 300. Leave the angle at zero and set the grid distance to 10 meters. This converts the center of OCAD's drawing area (0,0 by default) to (800,300) and the grid now reads directly in the last three UTM digits. Note that the x-y coordinates of the cursor at the bottom of the screen are now in UTM meters. Be sure to choose the offsets so that all the map area is in the first quadrant.
Open your waypoint graph as a template. You can ignore the resolution question (96 dpi is fine); you may need to adjust the draft scale roughly so the template is more or less map size. Options-AdjustTemplate and select in sequence a template waypoint, the point on the map grid that has that waypoint's UTM reading, a second waypoint, and the map grid point with the UTM reading, then Enter. The two pairs of points ideally should make a diagonal across much of the map area. OCAD then changes the scale of the template so these two points fit. It also rotates the template from true north to grid north.
Check that the UTM readings of other waypoints match the OCAD grid.
Digitize the waypoints using convenient symbols.
If an engineering map has been scanned or a TerraServer photo is available, open it as a new template and adjust it as needed so it fits the GPS points as well as possible.. Digitize its information.
Open the USGS map as a template, adjust, and digitize. Remember it is the least accurate source of information so use it only for such things as surrounding roads and buildings and for contours.
Start OCAD and open either BWSYM.OCD for a black only map or IOFSYM.OCD for a color map. Don't worry about map scale yet. Don't worry about magnetic north yet.
Options-OpenTemplate the topographic BMP file that includes the scale (accept the resolution of 96 dpi, but it doesn't seem to matter). The Options-Scale-DraftScale does matter and will need to be checked and adjusted. If you used IrfanView to capture a Terraserver screen image at 2 meter resolution, set the draft scale to 1:7633. If you downloaded and converted, try a draft scale of 1:19,500. Change the View scale and the view to see the scale bar. Select a line symbol and draw a straight line along the scale bar, then Edit-Measure it. The drawn (OCAD map) length should agree with the USGS scale length. If not, change the draft scale and repeat the process until agreement.
Then drag this drawn line of known length to the bar scale from my OCD file. It should agree; if not, something is wrong. Drag to select the bar scale and drag it to the bottom of the template and later include it in the printout of one section of the base map.
Draw roads, streams, obvious trails, and contours from the topo template. Draw buildings also, unless they are more obvious on the photo. Do not draw too much from the topo as most features will be easier to see, more recent, and more detailed on the photo.
If available, open the photo templateand Options-AdjustTemplate to fit the drawn information from the topo map. Do just a single point adjust by clicking one point on the template, then the same point on the map, then Enter. This avoids stretching/rotating, which is not wanted or needed. Several adjustments may be necessary until you are satisfied with the match; use View 4X. For the one map I have tried this way, the fit of the photo to the topo was excellent. Just to be sure, check the photo scale bar length as you did the topo one above.
It is neither necessary nor desirable to draw any of the features on the photo at this point. However, if buildings are more obvious on the photo, you may want to draw them. NOTE that it can be difficult to tell the extent of a building roof from the shadow of the building; similarly, the south edges of fields will look farther north than they are because of the tree shadows.
If an engineering map is available, open it as a template and try to adjust it to the USGS. Or you may want to reverse the process and use the engineering map first, then add to it from the USGS. Digitize all info from the engineering map.
The Terraserver topo and photo and the GPS as used above are oriented to GRID NORTH in the UTM (Universal Transverse Mercator) coordinate system. Terraserver does not provide the differences between magnetic north, grid north, and true north. You must get the difference between grid north and magnetic north from the published USGS map for your area.
If you will not use a GPS for field checking, use Extras-RotateMap with RotateSymbols NOT CHECKED to rotate the map to magnetic north. Set the grid to PaperCoordinates with a grid distance generally of 25 mm. Print the map with the grid. I use a 50% Green color.
If you will use a GPS in the field or if you have an aerial photo template do not rotate the map. Print the base map with the 10 m grid (may need to use 20 m for a 1:7500 base map). Then GPS readings can be directly plotted on the map in the field. Use a protractor or a hand compass and ruler to draw magnetic north lines across the base map at the proper angle to the grid north. You will need to rotate the map to magnetic north after field checking is digitized.
You are now ready to print the base map including the photo template if available. For a schoolyard you can print the whole area at once, but for larger areas, print the base map in several overlapping areas with fixed linear features as boundaries where possible. See the next section for choice of print scale.
Print-Options-PrintGrid should be turned off; the grid is not used here as the map will be rotated later to magnetic north. File-Print-Window-PrintScale and set the print scale (see below), then Window-ToPageSize then DefineWindow and drag to a smaller area for each base map section. Make sure the bar scale is included in one section of the base map print.
My iofsym.ocd file has the Map Scale (Options-Scales) set to 1:15000, which is the international standard for orienteering maps. My bwsym.ocd has a Map Scale of 1:5000. I recommend retaining these settings, while changing the Print Scale to print the base map and the final map at any other desired scales. If you can't stand doing it this way use Extras - Change Scale to change the map scale at any time.
When Print Scale differs from Map Scale, everything on the printed map is enlarged/reduced proportionally. For field checking, print the base map at 1:7500 or 1:5000 for color O maps or 1:5000 for black-only maps.
Draft Scale is only the scale of the template, so changing it only enlarges or shrinks the template.
Grid distance is in mm at Map Scale and can be changed at any time. Use it to help lining up legend items.
Symbol sizes are defined in mm at Map Scale. Symbol-EnlargeReduce-AllSymbols changes all symbol sizes, including text!!
A pace is two steps. Pacing is simply the counting of paces or double-steps from a fixed point to a new point. A pace scale converts the pace count to a distance in meters on the ground or to a distance on the map. A good starting pace scale is 60 paces = 100 meters.
Prepare a pace-count scale on both sides of the compass. Cut a 3 or 4 cm length of masking tape and place it over the edge of the compass. Lay this edge of the compass on the bar scale of the base map, which should have 100 m intervals. With a ball-point pen draw a tick mark on the tape at the compass edge at each 100 m interval. Draw another tick at the midpoint of the interval. Then draw two more ticks in each of these 50 m intervals to divide the intervals in thirds. This has now produced a scale of 6 intervals for 100 m. Each interval on the tape now represents 10 paces at 60 paces = 100 meters. You can refine this with experience.
Check the pace scale before starting field checking by pacing one or more obvious straight-line features (100 - 200 meters long) that appear on the base map. If the pace scale does not agree within 10%, redraw it.
In steep uphills or in tough going, count three steps as one pace sometimes to adjust for taking shorter steps. This can only be learned by experience.
Now you are ready for the fun part, going into the "woods" and fixing/improving your map to make it into an orienteering map. This can be as simple/crude or as complicated/detailed/accurate as you choose or as time and ability allow. The process can be repeated over time, adding more detail, fixing inaccuracies, and updating with each "revision". Neatness and care are important to prevent errors during drafting.
Field checking can normally be divided into three mapping stages: linear features, point features, and area features. But there are no hard rules about what order to map things in.
Field checking can be thought of as the process of adding more and more "fixed points", where a fixed point is a point feature whose location as marked on the map is accurate. But you must always be concerned that the base map may not be as accurate as you would like, or that things may have changed since the topo or photo were made.Field checking is also a process of repeated decisions about what to show on the map and what to leave off.
Two warnings:
For orienteering maps, the error in handheld GPS units may be too large for detailed, accurate mapping, though it is generally better in 2004 with the addition of more satellites to the system. Satellites may still be positioned such that errors of 20 meters are possible. This is four millimeters on a 1:5000 school map. If the error indicated ny the GPS is larger than 10 meters, wait an hour and satellites will probably be better positioned. Expect poor accuracy under dense canopies (lost of big trunks and branches). With care, good satellite locations, and without tree cover or other obstructions, accuracy improves to about 5 m or 1 mm on the map. Even expensive differential GPS will probably not be as accurate as it looks or as accurate as you wish it were. Accuracy deteriorates greatly right next to buildings because half the sky is obscured.
The best way to assess accuracy and improve it is to GPS everything at three different times at least two hours apart. Plot all the information and then use an average. This works for both point and linear features. It can be very enlightening about the size of GPS errors. This means walking all linear features (e.g. trails, walls, streams, field edges) three times, so don't do more than you need to establish a network of "fixed points".
The process for setting the compass for mapping is the reverse of the process for setting the compass for orienteering. At a fixed point (already on the map and checked for accuracy) hold the compass level six inches in front of your navel with the direction of travel (side of the baseplate) pointing in the desired direction (toward a point feature or in the direction of a linear feature). Rotate the compass housing until the north lines in the housing line up with the compass needle. This sets the angle between the direction to the object and magnetic north.
Pace the distance from the fixed point to the new object, carrying your compass with the bearing set on it.
Place the compass on the map board with the north lines in the compass housing lined up with magnetic north lines on the map, and the pace scale edge of the base plate on the fixed point. Measure off your pace count along the pace scale, and draw the new fixed point. If this is not a mappable feature, just make a dot. Otherwise, draw the symbol for the feature to be mapped.
It is usually not possible to draw on the mylar in the field with the exact map symbols that will be printed by the final OCAD map. So every orienteering mapper develops their own set of field-checking symbols. You can download the set I use as an OCAD file and then modify and print it in OCAD. Note I use a red pencil for "brown" features, and a brown pencil for "yellow" features. This symbol set shows the ISOM number for each symbol and gives relevant information about it. Obviously you need to learn what symbols are available and decide which you will use. I carry a copy of the symbol set in a map case taped to the back of my map board.
In the first stage, linear features such as trails, walls, streams, and edges of distinct areas such as fields and marshes are mapped. The most obvious of these are trails. At this stage, it is important that both the starting and ending points of the linear feature are already fixed points on the map, so some selection of what to map first is necessary. As an example, consider a trail. The mapper begins at a known starting point, takes a bearing and paces down the trail usually for as long as the trail stays straight. The ending point of this bearing is then plotted on the map as a point (see Setting the Compass above). Watch out for gradual curves; take a reverse bearing as a check. Then the bearing and distance to the next trail bend is measured and plotted. Continue plotting straight line segments until a fixed point on the map is reached.
At this point there will be a discrepancy or error between the location on the base map and the location reached by the series of bearing and distance points. This error is then prorated back through the series of points to give the final "fixed" location of the trail.
The assumption is that the error has been gradually accumulating rather than being caused by a single mistake in plotting one bearing/distance. In this process, it is important that the linear feature generally goes all in one direction. The method will not work if the trail circles around to near where it begins.
If possible, do another linear feature more or less at right angles before prorating error.
Generally do trails first, then walls, streams, edges of fields, lakes, and distinct marshes. Draw only dots connected with faint line as you will need to erase these after the prorating of error is done. Do NOT add lots of lateral features because you will have to erase and redraw them all when prorating the error. Use different color dots such as blue for a stream crossing or green for an obvious tree.
In areas where there are no linear features with fixed ends, it may be necessary to traverse the area from point feature to point feature from a fixed beginning to a fixed end, and then to prorate error over locations as for linear features. If there are no point features either, temporary ones can be created using flagging, or obvious, unique trees can be used. These are marked with dots (colored green for trees or brown for flagging) on the field work but are not put on the final map.
Point features can then be mapped by compass and pace from any of the fixed points of the linear features. If the mapper is accurate enough, adjacent point features will be in the right relative positions to each other. However sometimes fudging is needed. Remember, an orienteering map is not an engineering survey. The criterion for sufficient accuracy is that the orienteer will not notice any errors.
This may first require making one or more traverses across a subarea from point feature to point feature, often the biggest boulders, to another fixed point, then prorating error as for linear features.
If you work from one edge of subarea gradually across it, you are bound to be off when you reach the other side and will then have a lot of fudging to do. Always check relationships to other features and fudge as needed .
In the third stage, indistinct area features are mapped and contours are fixed. Contour features such as spurs and reeentrants (small valleys) may need to be mapped as linear features initially.
With experience, the field checker can use "plane table" and "eyeballing" techniques to speed the process. The field checker must be standing at a "fixed point". The map board must have a compass attached, and the board is oriented so that the north lines on the map line up with the compass needle. The direction from the fixed point to the new object on the map is then the same as its direction on the ground; the distance to the object is estimated by "eyeballing", and the new point is marked on the map.
In the plane table technique the distance is not measured but a line is lightly drawn on the map from the fixed point in the direction of the new object. From a second fixed point, the map is reoriented and a second direction line is drawn. The intersection point is the location of the new object. High accuracy requires a third intersecting line and locates the point at the center of the triangle formed by the three lines.
Make sure that each section of field checking mylar has several points drawn on it that are already on the OCAD base map. You will need these to align the field checking with the base map.
Then, in OCAD, scan the field work at 150 or 200 dpi to make a template. Options-AdjustTemplate using several pairs of points, clicking first on a scanned template point, then on the equivalent base map point. Press Enter after all the point pairs are clicked and OCAD will adjust the field work template to fit the base map.
Digitize all the information from the field work. Repeat the process for all the base map sections.
Use Control with a drawing tool to follow an existing curve. With the EditPoint tool, insert points with Shift-Ctrl and delete points with Ctrl. Toggle hatche-solid areas using Ctrl-H. Corner points restart tick and dot spacing so changing between a corner point and a regular point affects these.
Now it is time to choose a final map scale, preferably 1:15000 or 1:10000 for color maps and 1:5000 for black-only maps. Try a scale using File-Print-PrintScale, then after setting the page size in Printer Properties (often 8.5 x 11 inches), Window-ToPageSize-DefineWindow to see how the page size compares with the map. This tells you how much space you have for title, legend, and other information. It is useful to drag a rectangular border using my symbol 850.0 labelled Map so you can see how much space you have for layout.
If the map is still oriented to grid north, rotate it to magnetic north now, being sure the RotateSymbols is NOT CHECKED.
Draft the title, legend, and other information by dragging and correcting my stuff or creating your own. This is the artistic part. Make it look good. Change text symbol sizes as needed. A lot of selecting and dragging to new positions is done at this stage.
Delete unused symbols from the legend. To check if a symbol is used, click on the symbol in the symbol list, then Extras-SelectbySymbol will show the number of times it was used in the lower left.
To stay inside the 500 object Demo limit, select contour sections by Shift-clicking then edit-Merge. Do the same with any adjacent areas of the same symbol. Use Optimize/Repair to delete useless objects.
Do not use one symbol for two or more purposes; create a new symbol instead so any later change to a symbol doesn't have unintended effects.
You may choose to print all the final copies of the map using an inkjet printer at 600 or 720 dpi. For best quality on an Epson, use Photo Quality paper, but it costs 10 cents per sheet. Ink costs about 30 cents per page or more, so 40 cents per copy is a rough estimate of inkjet printing of color 8.5 x 11 maps. Color varies a lot among printers, so trial-and error is necessary to change printer colors in OCAD using Symbol-Colors to get the results you want. If you print a master map for later color photocopying, colors will change again depending on the copier, and quality can suffer greatly. Gray in particular does not color copy well, so avoid symbols that use it.
For black-only maps, the same issues apply, but involve only shades of gray. Again, trial-and-error is needed to get the gray shades right and photocopying tends to reduce quality.
So the best technique is to produce all your maps by printing directly from OCAD to a single printer. This also gives you the option of adding a course to the map using the purple symbols.
I used trial-and-error to match my printer's colors to the IOF standard colors, with the following results. These are the colors specified in iofsym.ocd .
| purple 100% | 25-75-0-8 |
| blue 100% | 80-15-0-0 |
| blue 50% | 45-10-0-5 |
| brown 100% | 0-35-60-35 |
| brown 50% | 0-23-26-17 |
| green 100% | 65-0-90-0 |
| green 60% | 45-0-55-0 |
| green 30% | 25-0-30-0 |
| yellow 100% | 0-25-100-0 or 0-30-100-0 |
| yellow 50% | 0-20-66-0 or 0-17-68-0 |
| yell100/grn50 | 8-0-60-28 |
| gray | 0-0-0-30 |
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