[talk-au] Using multipolygon to create large lake

Tue Apr 23 08:57:52 UTC 2013

Hi Michael

Much appreciated.  I found though the lake was not rendered but then refreshing and zooming in and out it did come up so the rendering is a little suspect, might be due to Telstra's 3G network issues or the use of Firefox.  

It appears once again I have fallen foul of Polatch 2 limitations as the relationship editor brings up a very basic menu as what you describe on the relationship attributes does not appear.  Frustratingly it shows the lake option but when you select the drop down box it is not an option so once again Polatch 2 crashes and burns as it does with adding peaks forcing the use of the advanced option, which by the looks of it does not exist for relationships.

Ok looks like I need to transition to JOSM.  Err, how do you even move around it?  I once attempted to use it but found it about as friendly as a dog with rabies.  O'well yet another piece of software to learn that has its own unique ways of doing simple things like moving around the screen!  Might be a good time to find the bottle of scotch and head to bed.

But anyway thanks for the help, muchly appreciated along with the hints.  And yes I do need to use JOSM as my editor but not tonight as my head hurts.

Cheers Brett

Date: Tue, 23 Apr 2013 09:57:25 +0200
Subject: Re: [talk-au] Using multipolygon to create large lake
From: ohrosm at gmail.com
To: brussell237 at live.com.au; talk-au at openstreetmap.org

Hi Brett,

2013/4/23 Brett Russell <brussell237 at live.com.au>

I have wasted an entire afternoon working on Lake St Clair in Tasmania by using multipolygon relationship to map Lake St Clair.  It is a big lake so to get any reasonable detail blows the 2000 point limit of OSM by using a simple polygon.  I have reached the point it will become a square of four points and renamed "Lake OSM of despair".  Annoyingly I was going well at it but then the wheels fell off.  I am using Polatch 2 and slowy being going mad as Bing has poor coverage of the area, the rendering takes forever, and driving me up the wall this is my first attempt at using this technique so no idea of it is me, or the every unreliable OSM rendering servers that flunk out on any decent mapping effort.  I get lovely squares of missing Bing photo that force save and view then edit.  The refresh option takes me to any zoom level that it thinks best to make me insane.  Sufficient to say OSM help is about up to the usual poor standard.  Polatch does nothing to help to find if you have broken links around the lake and I have been around the lake so many times hunting for such things that sanity and temper is at overload settings.  I have the usual OSM issue of half the world saying use coastline on large lakes and the other half saving no, use multipolygons.  

"Large" in this context means something like the Great Lakes in the US. You wouldn't want to use coastline for the Lake St Clair. One of the key drawbacks of using coastline is how long it takes the changes to be rendered. So I would always use multipolygons whenever possible.

 As you may have gathered by my words OSM's and Bing's failures have made
 this a nightmare of a place to map and almost broken my interest in mapping in OSM.  And to top it off my mega 
expensive Asus laptop is as flakey as ever with even a blue screen of 
death.  If another programs demands an update I will take extremely 
prejudiced action against the nearest programmer that I can find!!!  

Can someone please look at the Lake St Clair and tell me what on earth is the issue.   Please consider it an act of kindness or the provision of mental health service.

Just did so and it renders fine again.

As I'm using JOSM I can't really comment on the problems you've experienced with Potlach. The changes I had to make were all about tagging. So the natural=water etc. should go on the relation, not the individual ways. (I guess JOSM would otherwise complain about using an area tag on a non-closed way or so). Also the role for the ways had been set to "Lake St Clair" but should rather be "outer". This I also only found since JOSM complained about it.

Bye,
   Michael

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