[talk-au] Rivers that have dams on them

Brett Russell brussell237 at live.com.au
Tue Jun 18 09:47:12 UTC 2013

Hi Steve

The major deficiency with OSM on Garmins is the lost of critical bushwalking relevant details as you zoom out.  In a city environment losing highway=path and foot=designated ways makes sense to remove clutter as major roads are more important on the limited screen space.  But such charting logic fails badly in the bush where tracks need to hold in at high level zooms as does mountains and huts.  Often there is not a major roads for twenty or more kilometres.

I would like to work with OSM-Australia website to add the creation of bushwalking optimized img files for Garmins that has tracks elevated up the zoom pecking order along with mountains and huts.  Similar to the bike, minor road map, and streets with no names sets.  I believe that the scripts that make Garmin img files can be tweaked to do the rendering enhancements, but by all accounts not easy to understand but I am willing to give it a bash as an old Unix programmer.   

One of the advantages of routable track maps is the ability to measure the "actual" distance between destinations.  I used a Garmin Rino 650 to calculate the distance and then "measured" the distance covered using my Garmin Fenix.  Due to the limited number of points on the track the calculated distances were generally ten to twenty percent shorter than "measured" distance but still vastly better than the straight line distance.  This means I link huts and other infrastructure into the tracks via paths.

One thing I encountered myself, along with more than a few other walkers, is the very poor quality of commercial Garmin maps for bushwalking with Garmin Topo maps not even having the Overland Track marked!  Memory Map is a raster mapping system using Tasmap but the maps are often poorly scanned and many thirty years out of date.  Also the peaks are in the wrong place on Garmin maps and even with wrong names!  OSM mapping has given me the ability to build quality maps, and more importantly correct or add details.

As for allocating properties to objects such as huts OSM is rather, well, OSM.  In Polatch 2 they have a nice icon for alpine-hut which is driven by tourism=alpine_hut tag.  I came from the Polatch 2 introduction so stuck with that.  It appears to hold in well for Garmin zoom levels but not brilliant.  Mudmap 2 I found thanks to Li feedback gives the ability to select three POI to hold at all zoom levels.  Peaks, huts and campsite appear to work well.  When back from my walk I read up on the definition of alpine hut and the OLT huts are a reasonable fit as they are occupied by rangers or volunteers in the walking season but most huts in Tassie are not.  So I could accept that alpine hut was intended for more luxurious accommodation.  At the end of the day what is rendered is important as numerous tags crop in OSM that are not rendered.  In a way "wars" over tagging is rather meaningless unless the tags are rendered.  My pet hate is fell and scree.  Fell, as this means easy walking and camping while scree meaning challenging walking and no camping.  Neither are rendered in Garmin maps but are tags recognized by JOSM so rather hollow terms.  Polatch 2 does not even recognize natural-peak.  The rendering is critical as most bushwalking Garmins have small low resolution screens.  As for the website rendering I am reasonably happy with peaks and alpine-hut zoom rendering levels as I accept that OSM is more street based.  The ideal solution is profiles that govern zoom detail as not one set of rules meets all requirements.  

Locality is an interesting tag.  Pelion for example covers an area from the Rangers Hut to Old Pelion Hut.  It is better to have all identified than a single place=Pelion in order to navigate to in white-out conditions.

It was interesting watching two non OSM mappers using the OSM maps that I downloaded to their devices.  The hated that important bushwalkings features disappeared at higher zoom levels and on an Extrex 10 they had to zoom in to 200 metres to find the tracks so got lost in the "trees" when in a "forest".  Also the POI searches were strange.  My Rino on search would suddenly after two letters decide that I was going to say Penguin than Pelion.  They both commented that with minor tweaking OSM for Garmins would be a very useful tool.  One is now madly mapping the Penguin to Cradle Trail and become a fan of OSM mapping.

So my interest is maps on Garmin devices.  The beauty of img files is it does not take too much "geek" power to get most Garmins working with OSM.  Even my Fenix watch has OSM maps.


Brett Russell

> Date: Tue, 18 Jun 2013 17:55:02 +1000
> Subject: Re: [talk-au] Rivers that have dams on them
> From: stevagewp at gmail.com
> To: brussell237 at live.com.au
> CC: talk-au at openstreetmap.org
> On Wed, Jun 12, 2013 at 2:31 PM, Brett Russell <brussell237 at live.com.au> wrote:
> > I used OSM on a nine day Overland Track Wall and found it very good with the
> > Garmins that I was using.  Used the routable maps and found they were about
> > a one kilometre in ten understated on distance due to fewer nodes recorded
> > in OSM compared to the distance tracked by the GPSs.  Still very impressive
> > compared to the expensive and poor quality Garmin maps.  Need to work with
> > someone to get OSM bushwalking maps going as walking tracks, mountains and
> > huts need to be zoomed in a long way to see thus you get “lost” in the trees
> > finding them.   Also the search feature on the Garmin can be rather
> > “broken”, by that items do not appear in the all POI lists but can be found
> > in sub lists.  Bit more work needed by my to refine the tracks and the
> > features but gradually working my way south to north refining the track.
> Glad to hear it - I added the Overland Track a couple of years ago,
> with the major side trips. From memory, I just beat someone else who
> had also recorded the trace but hadn't uploaded it yet.
> Regarding use of 'correct' tags like alpine shelters etc, I tend to
> get very pragmatic and use tags like "place=locality" instead so they
> show up. And pretty much a place like Pelion Hut *is* a locality -
> it's a major landmark and navigational reference point.
> What exactly do you mean by "Need to work with someone to get OSM
> bushwalking maps going"? Going where? On a GPS? On a custom website?
> In the default mapnik rendering on openstreetmap.org? Static printed
> maps?
> Steve
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