Openorienteering Mapper for Open Orienteering Maps

1 Introduction

Openorienteering Mapper (OOM) is an awsome program but currently the documentation is very much focused on tools and not on tasks. Below I explain how to use OOM for different more and less common tasks.

2 Installation and Setup

On high-dpi (retina) screens the texts appear too small. One may attempt to set the Qt scale factor to 2 by setting the environment variable as

QT_SCALE_FACTOR=2

however, apparently this scales all pixels into 2x2 pixel dots and effectively halves the screen resolution. This is unfortunate for most other tasks, in particular the map display itself.

The way to change only size of the font is to specify font DPI with

QT_FONT_DPI=163

or whatever is a good DPI value for your computer. Larger DPI values will result in larger text.

Normally the map symbols in the Symbols window is too small too. However, it is easy to fix from the settings menu: choose File → Settings. In the settings window choose tab Editor and increase the Symbol icon size appropriately. 7mm looks good for me on a 163 DPI screen:

3 Editing Contours

3.1 Simplifying Contours

Contours are one of the most valuable aids for the runner on good orienteering terrains. Nowadays these originate typically from lidar data and it is all too easy to include too many details in the final map. As a result the contours may be hard to read, and instead of precision, the runner can only see a fuzzy mishmash of brown lines and dots. This problem is well acknowledged and ISOM 2017 states that

… but the demand for legibility must never be relaxed in order to present an excess of details and features on the map. (p 7)

It also states that

Small details on contours should be avoided because they tend to hide the main features of the terrain. Prominent features such as depressions, re-entrants, spurs, earth banks and terraces may have to be exaggerated. Absolute height accuracy is of little importance, but the relative height difference between neighbouring features should be represented on the map as accurately as possible. It is permissible to alter the height of a contour slightly if this improves the representation of a feature. (p 13)

So, lidar contours must be simplified.

However, when simplifying the contours on the map, it is still good idea to retain the detailed lidar contours for future reference. As a solution I recommend to create an additional contour type (let’s call it “lidar contour”), so we will have 4 different types of contours: normal contour, index contour, form line, and lidar contour. For normal map use one should hide the lidar contours (by right-clicking on the corresponding symbol).

The simplification workflow will look something along these lines:

1. Select the appropriate contour.
2. Duplicate it using Duplicate tool (Tools → Duplicate, or press d). This creates an identical copy of the symbol in the same location.
   Note that you may be tempted to use copy and paste instead of duplicate. This will not work as paste does not preserve the location of the contour, and manually moving a contour to exactly the right place is virtually impossible.
3. Select the lidar contour symbol (from the Symbols window)
4. Select Switch Symbol (Tools → Switch symbol, Ctl-g). Now one of the formerly identical lines is of different symbol, and if you make lidar contours visible, you can see it. If the lidar contours are not visible, you can see how the contour suddenly becomes unselected–the selected contour becomes invisible, and from underneath the visible duplicate of the original pops up.
5. Select the original, non-lidar contour. An easy way to achieve it is to protect the lidar contours (by right-clicking on it’s symbol in the Symbols window).
6. And edit it in any way you wish!

Note that good tools for simplifying contours are Convert to curves (Tools → Convert to curves, n) if the contour is originally a polygon, and Simplify path (Tools → Simplify path, Ctl-m). The resulting curves are much smoother, feel less uneasy, and are much more helpful for keeping runner’s focus on the most important features.

Here is an example how I have shifted the contour (think dark line with handles) down to the next lidar contour in order to make it follow a re-entrant better. The re-entrant was much more visible on terrain than the rectangular cut the lidar contour (thin brown line) was following. So I shifted it down by approximately 1 meter (lidar contour interval is 1m in this figure).

4 Working with vegetation

4.1 General drawing

Vegetation (and other area symbols) can be drawn using the path tool (Tools → Draw paths, or p). The basic drawing is simple:

1. select the area symbol
2. click on the map where you want the object to be
3. click at each corner of the object
4. finish with a double-click. Note that the double click finishes and closes the symbol, but does not create an additional corner.
   Alternatively, you can finish and close the object with right-click, this creates a corner.

However, this way of drawing creates polygons, not smooth objects. You can draw smooth curves by repeating the above but holding down the mouse button while drawing. The result may still look somewhat chunky, so you may want to edit the control points afterwards. Alternatively, you can draw a polygon and convert it to curves, using the convert-to-curves tool (Tools → Convert to curves, or n).

4.2 Joining and cutting areas

When editing the map piece-by-piece, you end up quite often extending areas of the same type. You can achieve this by editing the area boundary line, but usually it is more convenient just to create a new patch of the same color. As a result, the map contains two (or more) patches of the same type vegetation next to each other and partially overlapping. Normally this is indistinguishable from a single unified area made of both these patches, so you may just keep it as it is. But there are at least three reasons you may want to merge the areas of similar color:

1. Normally Mapper uses a color priority to determine which color “wins” and will be visible. However, if using the map as background template (for instance, when preparing maps for fieldwork), the objects will be overlayed as semi-transparent layers and the overlapping areas will be darker. This does not look good and may be confusing.

The area overlap is not normally visible on the map (left). However, on a semi-transparent background template we can see that the map consists of two partially overlapping olive green patches, overlaid on a yellow square (middle). The right image show the same template, but not the two olive green areas are merged and cut out from the yellow square.

2. When doing various operations, such as moving, changing symbols, or cutting out holes, you have to select all pieces separately. This may be laborious, in particular in case where there are many different items nearby.
3. And finally, single areas are simpler and cleaner to handle and understand.

4.2.1 Joining areas

Joining areas is fairly straightforward.

1. Select all the patches you want to merge. You may prefer to only include areas of the desired type, but nothing bad happens if you also include contours and a single object of another color.
2. Use Unify Areas tool (Tools → Unify Areas, u). This will merge compatible areas (those of the same color) while leaving contours untouched.
   The tools will merge all selected area objects that can be merged. Line- and point objects are not changed. If you have selected different type of objects, it attempts to merge all objects by type, so you end up objects of similar type joined together. Object type is never changed.
   When none of the objects can be merged, it fails with an error message.

4.2.2 Cutting areas out

Like in case of joining, you may want to cut one are object out of the other for clarity. However, there is one additional reason for cutting. Namely, Mapper uses a color priority order to determine which object is visible. For instance, water has higher priority than green forest.

Drawing a light-green headland in water. It won’t work (left) as green goes underneath the blue. You either have to manually adjust the boundary of the body of water, or rather like done here, cut away the headland from water (right). The apparent imprecise right side of the cut is caused by a white object (forest) that is of higher priority than light green but lower priority than blue.

Cutting an area out of the other(s) is easy:

1. Select the area you want to cut away (make visible). Only areas can be cut away from other objects, areas and lines.
2. Choose Cut away tool (Tools → Cut away, no keyboard shortcut). The object you want to cut away will be replaced by a thin red border line.
3. Select all the areas you want to cut this object out of. This may include multiple objects, and both areas and lines. Everything goes.
4. Press main keyboard Enter.
   Note: numeric keypad Enter is not working for me.

You are done. Note though that point objects, such as boulders, will either be visible or invisible, you cannot have only a half of a boulder cut away.

4.2.3 Cutting holes into areas

Sometimes it is helpful to remove vegetation close to certain objects for clarity. For instance, prominent trees and other vegetation objects (symbols 417, 418, 419) are hard to see on green background. A solution is to remove the green, and potentially also contours and other map elements that interfere with legibility.

Without additional work, the prominent tree (417) and a rootstock (419) are hard to spot (left). Cutting a hole in vegetation improves the legibility (middle), cutting the contours and the black trail makes these objects even easier to understand.

Note there is another, hard to see rootstock in the yellow rough open land. The length of the black trail here (507) is only about a half of the specified minimum length

Cutting a hole in the vegetation (and other area symbols) is simple:

1. Select the area symbol you want to cut the hole in. Mapper only let’s you to cut a hole in a single selected symbol, you cannot select and cut multiple symbols at the same time (0.8.4). Cutting a hole also only works with an area symbol, the lines must be cut or adjusted separately.
2. Select the Cut free form hole tool (not the Cut object tool next to it!). When you click on the adjacent small arrow, you can choose between free form, circular, and rectangular holes.
   Free-form holes are created in the same way as area symbols. For round holes you have to click first on one, and thereafter on the other side of the hole, and for the rectangular hole you first have to click on one corner, select the angle, and thereafter the other corner.
3. If you have more than one area involved–either you have not merged similar colors or you want to cut into a color boundary area–you have to repeat the procedure with other objects.

As the figure above suggests, you may also want to cut the contours and other line objects. I haven’t found any direct references about how should one handle these cases. As ISOM 2017 repeatedly stresses the readability I would prefer the example here with both vegetation and line features removed around vegetation objects. However, this admittedly depends on how many other small features are there near the objects.

For some reason, cutting holes do not let you to cut the object into two parts–the result must remain connected. If you split the object, one side will just vanish. Use cutting areas out tool instead.

5 Preparing fieldwork maps

(Mapper 0.8.4) Maps that are good for running are not necessarily good for fieldwork. I prefer

• large scale, such as 1:3000
• pale color for area symbols (greens and yellows), so it is easy to write notes on those areas
• dense contours, at 1m or even 50cm intervals, as these help to pinpoint locations on slopes.
• keep symbols not scaled (violating ISOM 2017), so the symbols, and lines (in particular contours) are not too thick on the worksheets.
• in areas of sparse trees, I like to have individual tall trees visible (using a lidar template). This makes it possible to locate yourself incredibly precisely.

Some of it, like rescaling, is easy to achieve, but if you just make the map transparent to achieve pale area colors, you also get thin lines (in particular contours) hard-to-see. So instead I add the same map as a semi-transparent background template to a version where the areas are made invisible.

Mapper does not provide an automatic method to achieve all this, so I proceed in a following manner:

1. Create a copy of the original map and rename it to something like map-fw.omap.
2. Rescale the map to 1:3000 while retaining the symbol sizes
   
   Note that you want to ensure that templates, lidar images of trees, are scaled too.
3. Now it is time to hide all objects you want to be invisible, such as former fieldwork tracks, or other notes you do not want to appear on the worksheets.
4. Next, ensure that all objects you want to appear are visible. In particular, 1m contours may normally be invisible.
5. Now make another copy of this map as a background template. Call it something like map-fw-bg.omap.
6. Now we have done all the preparatory work. Re-open the map-fw.omap and add the map-fw-bg.omap as the background template to it.
7. Make the background template semi-transparent. 50% is too much in my opinion but it obviously depends on your map and printer.
8. Now make all the relevant area symbols invisible (right-click on symbols and choose Hide objects with this symbol). You should still see the areas through the semi-transparent background template. You may want to check if you have removed all of these by making the template invisible.
9. Finally, ensure that the other templates are in the right order. For instance, to be able to see the lidar trees on yellow background, you have to put the lidar image template above the background template.
10. Finally export it as pdf (or more likely as multiple pdf-s). Note that you have to select Show templates to make the pale background (and other templates) visible. An earlier version of Mapper did not handle templates well when outputting vector graphics pdf-s but 0.8.4 seems to have no issues here.

Print and you are done! Enjoy your day outside!

6 Preparing Final Maps

6.1 Add Images to Maps

Images (at least jpg-images) can be added as templates. When added, you need to manually adjust the size in the template positioning window. Click on the corresponding template in the template setup window and choose Edit-Positioning:

To open template positioning window, you just choose the required template (here all4o.jpg), and click Edit-Positioning.

Afterward you have to adjust X-Scale and Y-Scale, small numbers will give you larger image on the map. In case the image itself is small (in terms of pixels), you need rather small scales, e.g. 0.005.

You also have to ensure that the image is visible, and probably you want to place the image template above the map.

6.2 Clip Only Part of the Map Visible

Typically the fieldwork/raw maps are much larger than the particular competition area and we want to clip the final map into a size that only covers the latter. This can be done easily using Clip tool (and it is also explained in the manual, under FAQ).

1. Make a copy of your map. You may want to use this copy for adding/editing the computetition-specific information, e.g. adding a marked route to start or adding sponsors’ images, something that is probably not needed for the next event.
2. Select an arbitrary line tool (e.g. watercourse) and draw a line around the desired region on the map.
3. When done, close the line with Enter (not with double click or right click). This ensures that the result will be a closed line.
4. Select the line using Edit objects tool .
5. Click Clip .
6. Press Enter.

This removes the rest of the map and leaves only the region inside of the line visible. If you want to decrease the size of the map, you can click Edit - Clear undo/redo history. But needless to say, you cannot undo the operation afterward!

Note that up to Mapper 0.9.5, the tool was called Cut away and its icon was slightly different.

7 Technical Tasks

This section contains information about more technical tasks that are not directly related to creating maps.

7.1 How to Change the Symbol Set

(OOM 0.9.3)

Chances are that you want to update an old map that is using an old symbol set. OOM contains various updated symbol sets, including ISOM 2017-2, so one can give it a try. However, updating an existing map symbols may be quite a bit of a task, as the old and new symbols may not correspond well. Even more, as symbols are embedded in maps, the map may have non-standard custom symbols used for different objects. Symbols are made of colors, and maps also embed colors, and not just plain colors but colors in a priority order, namely which color will overlap another color. All this may make the symbol update a hot mess.

But if you still want to do it, you should follow broadly the following steps:

1. Ensure you have backed up your map file.

2. Figure out where are the desired symbol sets saved. Mine are saved in /usr/share/openorienteering-mapper/symbol sets/, and inside this folder in the folder corresponding to the map scale (e.g. 10000). How on earth did I figure this out? – you may ask. I attempted to load a CRT (symbol description) file (Symbols → Load CRT file …), and that dialog gave me the hint:

   

   Unfortunately that window only lets you to choose CRT files, but the symbols we are talking about are not in CRT but in map files. So you can click on the scale folders but those look empty as they only contain .omap files.

3. Select Symbols → Replace symbol set… This opens a window asking the map file where to load symbols from. This may seem somewhat counterintuitive, as we want to load symbols, not a map. But as explained above, symbols are embedded in maps, so to load symbols, you essentially have to load an empty map with these symbols. Now navigate to the desired symbol set map, in my case it will be /usr/share/openorienteering-mapper/symbol sets/10000/ and pick the desired map, e.g. “ISOM 2017-2_10000.omap”. This brings up the “Replace symbol set” dialog:

   

   As one can see, OOM does a pretty good job with trying to find a replacement symbol for former symbols. However, the job is far from perfect. In this example, ISOM 2000 symbol “527 settlement” is being manually replaced by ISOM 2017 symbol “520 area that shall not be entered”. If not doing this manual replacement, these objects will retain the old symbol in the updated new map, possibly with wrong priority. I recommend to browse through the replacements and fix manually as many missing ones as possible.

   But symbols from different symbol sets do not correspond exactly to each other. For instance, large green circle is defined as “special vegetation feature” in ISOM 2000 and “prominent large tree” in ISOM 2017. Hence automatic conversion is not even possible. On top of that, OOM has it’s own private symbols. For instance, for “601 magnetic north line”, ISOM 2017 says that “In areas with very few water features, blue lines may be used”. OOM solves this black/blue ambiguity by introducing slightly different symbols (601.1, 601.2, 601.3, 601.4 for black and blue single lines and line patterns).

4. Manually replace/remove unused symbols. After updating the symbols, the retained original symbols stay in the beginning of the updated symbol list. One can right-click on those and choose “select all objects with this symbol”. This selects all corresponding objects. Now you can click on the new replacement symbol, and choose Tools → Switch symbol (Ctr-g). This will replace the old symbols with the new ones. Afterwards one can right-click on the symbol again and delete it from the table. For instance, in the example map there was a symbol “418.0 Vegetation: very diffic. to run”. Note that this symbol is not in the ISOM 2000 standard, so I don’t know where did it come from. Right-click on this symbol, select all objects with it, click on “410 Vegetation: fight” and press Ctr-g. Now we can delete the old symbol 418.0.

   Continue in this fashion until all old symbols are removed.

A word of warning: I don’t know if this may mess up something, e.g. map several old symbols onto a new symbol. I also don’t know if deleting a symbol will purge the related unused colors.