David Currie

I spend a couple of hours a week hanging around the leisure centre at Fleming Park while Emma swims. For the past month or so, I’ve been using that time to update the orienteering map of the area, ready for the SOC Summer Series event there in August. The fairways of the old golf course are becoming increasingly overgrown, aided by the planting of lots of new trees. I therefore wanted to update the map to the latest sprint specification, ISSprOM 2019-2, so that I could make use of the ‘rough open with scattered bushes’ symbol. Although it hasn’t shifted much since 2016, I thought it was also time to update magnetic north.

The following directions for OpenOrienteering Mapper (OOM) are based on those I received from the club’s mapping officer, Mark Light.

Updating the symbol set

1. Download and unzip the latest symbol set from the British Orienteering website.
2. To make your life easier in step 4, delete any unused symbols from the map.
   1. Right-click on the symbol palette and click Select Symbols > Select Unused.
   2. Right-click on any unused symbol in the palette and select Delete.
3. Select Symbols > Replace symbol set… and select the
   appropriate scale set of icons from the download in step 1. If, as in the case of this map, the scale doesn’t match, you’ll get a warning.
4. Provide a mapping for each symbol in the old set to the new.
   1. You can use the Symbol mapping dropdown at the bottom of the dialogue to determine whether it matches by textual name or ID number by default.
   2. Work your way down the list, checking where there is no mapping specified. If the old symbol is something custom that you want to carry across, for example, text for a legend, leave the selection as -None-. Similarly, if you’re not sure what it should translate to, just take a note of the number and leave it as -None-.
   3. Click OK.
5. Map any symbols you were unsure about
   1. Right-click on each symbol in the symbol window and click Select all objects with this symbol.
   2. If you can now work out what they should be mapped to:
      1. Select the new symbol in the symbol window.
      2. Click the Switch symbol icon in the toolbar.
      3. Right-click on the old symbol and select Delete.
6. Particularly for any custom symbols you’ve carried across, check that they are still visible on the map. It may be that, as with this map, they have been given a colour that is now lower down the colour table than some symbol that appears above them. Either double-click on the symbol and edit it to use the correct colour from the specification, or select View > Color window and re-order the colours so that the symbols reappear.
7. If, in step 3, you received a warning about the symbol and map scales not matching, now is the time to fix that.
   1. Select Symbols > Scale all symbols….
   2. Enter the scale percentage. For example, when using 1:4,000 symbols on a 1:5,000 map, enter 80%.
   3. Click OK.

Updating magnetic north

1. Determine the magnetic declination applicable to your map.
   1. Open this website in a browser.
   2. Drag the marker to the location of your map and note the current magnetic declination. OOM will only accept two decimal places, so don’t worry too much about the exact position of the marker.
2. Ensure that the map is correctly georeferenced with the correct projection, in our case, the Ordnance Survey British Grid (EPSG 27700). These settings can be found under Map > Georeferencing….
3. If it doesn’t already exist, create a new ‘part’ in OOM for the map furniture (borders, legend, north lines, and anything that shouldn’t change with magnetic north).
   1. Select Map > Add new part….
   2. Name the part Furniture.
   3. Click OK.
   4. A new dropdown appears in the toolbar showing the currently selected part. Select the default part.
   5. Select the items that make up the furniture, either on the map or via their symbols. Select Map > Move selected objects to > Furniture. Repeat until all of the furniture is in the new part.
   6. Under Map > Georeferencing… enter the declination you retrieved in step 1 and click OK. This will rotate all parts of the map to account for the current position of magnetic north.
   7. Now you need to rotate the furniture back.
      1. Select the Furniture part.
      2. If you don’t already have a grid displayed, select View > Show grid.
      3. Select Tools > Rotate objects and rotate the furniture part to align with the grid.

This entry was posted on Sunday, June 15th, 2025 at 8:19 pm and is filed under Orienteering, Technology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.