[talk-ph] Luzon Coastline

maning sambale emmanuel.sambale at gmail.com
Fri Feb 20 09:29:23 GMT 2009

FYI,  I will be contacting all mappers around the area following the
advice here:

On Fri, Feb 20, 2009 at 5:10 PM, maning sambale
<emmanuel.sambale at gmail.com> wrote:
> Just had a look at the area and coastlines seems sane.  AFAIK,
> coastline are not rendered regularly.   Rendering of coastlines comes
> from shapefiles based on OSM and not directly from the OSM dbase.
> On another note, I browsed around the general area Subic, Castillejos,
> San Narciso, San Felipe, Olongapo.  It seems a lot of data are added
> the past weeks.  Along with a whole lot of errors:
> unclosed areas
> overlapping highways
> unconnected and duplicate nodes
> missing nodes on intersections
> (Didn't touch anything today, though)
> I'm curious (and suspicious) about the data source.  I see no yahoo
> imagery, not even a public GPX trace.  This issue has been discussed
> before:
> http://lists.openstreetmap.org/pipermail/talk-ph/2009-January/000312.html
> And I did flagged the attention of one mapper.
> As I see no "proof of authenticity" I am again questioning these
> edits.  I know it's a wiki.  May I ask other members of the group to
> contact the respective mappers?  I am not discounting the fact that
> local knowledge maybe the source (ianlopez did great in San Pablo only
> with landsat and local knowledge), but can we discuss this first with
> the mappers? And hopefully avoid edit war.
> On Fri, Feb 20, 2009 at 4:40 PM, Ed Garcia <eppgarcia at gmail.com> wrote:
>> I also tried to "trace" that coastline section too a few days ago via JOSM
>> and was looking for possibility of "unmerged coastline nodes" somewhere.
>> Found none.
>> That section that went AWOL could be it.  Can't wait for Wednesday.
>> Thanks Jim!
>> :>)
>> On Fri, Feb 20, 2009 at 4:20 PM, Jim Morgan <jim at datalude.com> wrote:
>>> I've been trying to figure out the Luzon coastline around Zambales, as its
>>> driving me nuts. Personally I think it looks terribly offputting to see such
>>> a glaring error, especially as we're seeing some new members recently.
>>> So I looked at the coastline checker here,
>>>  http://tile.openstreetmap.nl/coastlines.html?zoom=9&lat=15.1027&lon=120.35419&layers=B00T
>>> and, using the notes here
>>>        http://wiki.openstreetmap.org/index.php/Coastline_error_checker
>>> investigated a few of the Big Red Dots.
>>> From looking at them in JOSM, the Big Red Dots seem to be at areas where
>>> the coastline is split into different sections. The sections have the same
>>> tags i.e.
>>>  layer=-1
>>>  name=Luzon
>>>  natural=coastline
>>> and the direction is correct -- wet on the right.
>>> But they have different description and Notes fields.
>>> Is this the problem then? That the notes fields are different and that
>>> this has somehow made the renderer unable to recognise that they are the
>>> same coastline? I can't imagine that it is ... Or do the coastline segments
>>> need to be joined together?
>>> I understand that the islands outlined in red are only being flagged as
>>> wrong because they are currently "on land" so those will disappear when we
>>> get the coast corrected.
>>> Possibly related to this, I noticed that a section of the coastline had
>>> gone AWOL around Subic airport, and actually cut across the runway, so I put
>>> in a temporary section of coastline so that the coast goes outside the
>>> airport. Its very approximate at the moment, but at least it is
>>> topologically sound.
>>> Maybe I'll wait and see if this glitch was causing all the problems. I'm
>>> crossing my fingers that I haven't made things worse, but I thought I'd
>>> mention what I've been doing here, so that if the sea suddenly drains away
>>> from the entire Asian subcontinent, you'll know where to point the fingers
>>> of blame (and where to go to start fixing things ... .).
>>> If anyone else has any bright ideas on how to fix this coastline, please
>>> help me out here. I'm a little out of my depth (no pun intended), but its
>>> been broken for several weeks.
>>> Jim
>>> --
>>>   datalude: information security
>>>   e: jim at datalude.com
>>>   Philippines: +63 2 403 1311 / mob: +63 920 912 5830
>>>   Hong Kong: +852 9100 7586
>>>   w: http://www.datalude.com/
>>> _______________________________________________
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>>> talk-ph at openstreetmap.org
>>> http://lists.openstreetmap.org/listinfo/talk-ph
>> --
>> website administrator:
>> - www.waypoints.ph
>> - reeflife.eppgarcia.com
>> PADI Divemaster #491048
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> --
> cheers,
> maning
> ------------------------------------------------------
> "Freedom is still the most radical idea of all" -N.Branden
> wiki: http://esambale.wikispaces.com/
> blog: http://epsg4253.wordpress.com/
> ------------------------------------------------------

"Freedom is still the most radical idea of all" -N.Branden
wiki: http://esambale.wikispaces.com/
blog: http://epsg4253.wordpress.com/

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