robbieonsea's diary

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Creating a Map for a Garmin Edge 520

Posted by robbieonsea on 22 July 2017 in English (English)

If you are an owner of a Garmin 520 device, you may have discovered the device has the capability to use custom maps in the standard Garmin .img format. Unfortunately the device has quite limited internal storage (up to around 100MB) and no external SD card capability.

Storage space can be increased by removing the default Basemap and maps of your choice (e.g. your local area) can be acquired via the excellent [OSM Garmin Maps] ( website.

Further information about doing this can be found via these blog posts:

However consider the needs of the long distance cyclist - such as a participant in London Edinburgh London, the premier Audax UK event - in this scenario the above available maps needed to cover the area being travelled will be too big to fit on this device.

One can use OSM data directly and process the data yourself using Open Source tools to generate a gmapsupp.img file that covers your area of interest. My operating system is Debian Linux so the tools needed are available, of a modern enough version and easy to install via the standard operating system ‘apt-get’ manner:

Those using Windows or Mac OS’s can run these tools but installation is normally more intricate and one will need to refer to the individual websites for specific instructions.


My method for generating a suitable gmapsupp.img is thus:

  1. Download a OSM data extract in PBF format - Geofabrik
  2. Run osmosis to remove and contain only the relevant data wanted for the map.
  3. Create the map using mkgmap, using the default style.
  4. Transfer to your Garmin device and enjoy.

All these steps can be easily scripted to be able to run with different parameters, such as adjusting the data being used or for a newer dataset.

Note if you run mkgmap directly on an Great Britain extract, the resultant map is 220MB and thus too big to fit on a 520 device. Hence the osmosis commands are used.

Detailed Process

Here are my osmosis and mgkmap commands in shell script with approximate timings of the operations on my desktop PC (1.4GHz).

export myPBF="great-britain-latest.osm.pbf"
export poi_tags="amenity=toilets,fast_food,cafe,pub,shelter shop=convenience,supermarket,bicycle"

osmosis \
    --read-pbf "$myPBF" \
    --tf accept-ways \
        highway=* \
        waterway=river,canal \
        railway=rail,preserved \
        natural=water landuse=reservoir \
        $poi_tags \
    --tf reject-ways highway=path,footway,track,bridleway,service \
    --tf reject-relations \
    --used-node \
    --write-xml ways.osm
# ~15 mins

osmosis \
    --read-pbf "$myPBF" \
    --tag-filter accept-nodes place=* natural=peak $poi_tags \
    --tf reject-nodes place=isolated_dwelling,farm \
    --tf reject-ways \
    --tf reject-relations \
    --write-xml nodes.osm
# ~2 mins

osmosis --read-xml ways.osm \
        --rx nodes.osm \
        --merge \
        --write-pbf \
# ~3 mins

mkgmap-splitter reduced.pbf
# ~1 minute

mkgmap --index --gmapsupp 63240*pbf
# ~4 minutes

The resultant gmapsupp.img file is 77MB big, so fits easily on a Garmin Edge 520 device and can be transferred to the device by a file copy to the usual “Garmin” folder location on the device.

A copy of this specific gmapsupp.img is on Dropbox


Alternative strategies for creating a smaller map file could be to define a smaller data area via a simple bounding box or a more complex polygon or trying to customize the mkgmap style rules but I haven’t tried these.

I will be participating in LEL next week - wish me luck :), but I will be using my trusty Garmin eTrex 20 - which having 2Gb internal storage - with the free standard map provided by - as per my normal outdoor cycling and walking (and on the side OSM surveying) activities.

I generated this mainly for a good friend who has a 520 device, but hopefully the above example will be useful for others to use directly or tailor this process for their needs.

Location: Southsea, Portsmouth, South East, England, PO5 3DU, United Kingdom

Finding Buckingham Place

Posted by robbieonsea on 14 December 2015 in English (English)

Recently I have be watching The Prisoner on DVD; and having been to Portmeirion this year to the No.6 Festival, I thought I’d find out where Buckingham Place (as shown in the opening credits of The Prisoner) actually is.

With an eye to view the street as well, I turned to the all seeing eye of No.2^H^H^H, I mean Google. However Google infuriating thinks I mean ‘Buckingham Palace, London’ and centres the map there, no matter how I enter ‘Buckingham Place, London’ even when itself lists ‘Buckingham Place, London’ as one of the options after typing Buckingham Place (and listing Buckingham Palace separately).

OSM to the rescue!

Entering in “Buckingham Place, London” into the search box on the OSM website leads one to the one and only result of Buckingham Place.

Interestingly Buckingham Place is rather near Buckingham Palace, less then 1/4 of a mile away.

Sadly Mapillary’s search is much worse and returns no relevant answers, but currently there are no images of this road anyway.

Be seeing you.

Location: Victoria, Westminster, London, Greater London, England, SW1P 1NL, United Kingdom

Winter Warmer Pubs

Posted by robbieonsea on 1 February 2013 in English (English)

It would be nice if more pubs where tagged with real_fire=yes to determine whether the pub has an active and frequently used fireplace when it’s cold outside.

At the moment this is barely used tag, but would be quite interesting to see it used on a large scale.

I would encourage all mappers to consider this tag value and update any known places - may be including some research this weekend or any other time it’s cold around where you are.

It must be noted that in ‘surveying’ a pub in summertime it can be hard to determine if any fireplace is in actual use during the colder months. One may have to ask the staff or inquire with a local drinker.

There are other websites that list the real fire (among the many) properties of pubs (of course do not copy any copyrighted data), but from my local knowledge they seem fairly inaccurate - seems more like saying they have they a fireplace capability - even though they never or so infrequently use them that it shouldn’t part of a reason to go there.

It may be some time before any pubs with fires are rendered on the standard maps (flaming pint anyone?), but with the new Overpass Turbo it’s quite easy to do a search on even reasonably large areas, such as Hampshire (a UK county size).

Simply like:

<query type="node">
  <has-kv k="amenity" v="pub"/>
  <has-kv k="real_fire" v="yes"/>
  <bbox-query {{bbox}}/>

Of course this can be improved just to include pubs marked as building areas.

Location: Buckland, Fratton, Portsmouth, South East, England, PO2 7PS, United Kingdom

Waypoint Symbol Aide Memoir

Posted by robbieonsea on 26 October 2012 in English (English)

Harry Hill style, gotta have your (waypoint) system:

  • Ultravox ; post_box
  • Steve Coast ; guidepost
  • Eddie Izzard ; barrier bollard
  • Frederick Ramm ; ice cream van

But short of trying to invent a Famous Name to a Mapping Feature as an aide memoir, here is my list of waypoint symbols I create (on a Garmin Etrex Legend HCx) whilst out and about on foot or bicycle in England and their meaning:

Symbol | Meaning

  1. Flag, Blue Stile
  2. Flag, Green Gate
  3. Flag, Red Public Telephone [1]*
  4. Block, Blue Bridge
  5. Block, Green Kissing Gate
  6. Block, Red Postbox. Maybe stop* and photograph for extended detail.
  7. Pin, Blue If at begining or end of a way - highway bridleway (i.e. ROW), otherwise in middle of a way - highway track (i.e physical)
  8. Pin, Green If at begining or end of a way - highway footway (i.e. PROW), otherwise in middle of a way - highway path (i.e physical)
  9. Pin, Red   Middle of a way - highway service
  10. City, (Small) On road transistion between 30 mph zone to National speed limit. Off road transistion between path and track.
  11. City, (Medium) Unused
  12. City, (Large) (Symbol is large green blob) Misc feature is here - as an aid to memory. Maybe stop* and photograph.
  • If out cycling especially on road often I don’t want to stop just to map minor details (they could already be mapped anyway). If I stopped and photographed things, then one can geolocate them using the photo timestamp and tracklog - so you don’t need to waypoint it.

[1] I used to map telephones, but don’t do so much any more: a. Telephones out in the UK countryside, may not be in active service anymore. So can’t tell just by passing on bicycle. b. It’s more and more likely you’ll be accessing the map via a mobile telephone in the first place.

The advantage of this method is in not having to stop when cycling to get a first pass level of detail. Using only a limited subset of waypoint symbol makes it possible to create them on the move. Especially for the telephone as there is a waypoint symbol for it, you have to scroll around using a joystick on the GPS device which can be tricky (and take too long and thus dangerous) when on a bicycle.

Obviously other symbols can be used for the normal meanings: places of worship, parking, etc…

One can come up with various schemes to use these points for quickly mapping the details relevent to you.

Location: Hilsea, Portsmouth, South East, England, PO2 9RN, United Kingdom

Joined Help

Posted by robbieonsea on 10 April 2012 in English (English)

I finally got around to joining since today (well technically yesterday as I write at night) the weather in the South of the UK has been conducive to indoor activities.

I’m up to 91 points ( - yay go me! But that’s much to self congratulatory for my normal British manners.

One day I may even get around to setting up a picture of myself as an avatar - but for now I’ll leave that to Facebook & Google to join the dots of my various online activities…

Location: Spithead, Portsmouth, England, PO12 2AW, United Kingdom