[OSM-newbies] projection question in Hawaii

[Randy George]

Hi,

	Perhaps the island is offset. This test case lets me show OSM over
VE: http://www.web-demographics.com:8087/ The offset appears consistent
around the Island. Yahoo and VE align. Also the intersection locations align
on Google Earth

	The cyan tracks in this test are from GPS:
http://www.web-demographics.com/Exacter/test.html and you can use the infor
check map click to get the GPS record behind any of the points.

	The offset seems consistent around the coast.
		dx= -0.002608
		dy = 0.003020

randy

-----Original Message-----
From: newbies-bounces at openstreetmap.org
[mailto:newbies-bounces at openstreetmap.org] On Behalf Of swanilli
Sent: Wednesday, April 01, 2009 6:49 PM
To: newbies at openstreetmap.org
Subject: Re: [OSM-newbies] projection question in Hawaii

Maybe this is evidence of a wider problem with Pacific Islands that
are close to the International Dateline.

I have noticed that the location for the country tags for both Fiji
and Tonga are a long way from their true location.

For Fiji the country is located on OSM at
http://www.openstreetmap.org/?lat=-28.08334&lon=-179.99&zoom=15. This
is probably a typing error (someone hit tie 2 key instead of 1) and
probably was meant to be
http://www.openstreetmap.org/?lat=-18.08334&lon=-179.99&zoom=15 which
would put it in the middle of the Fiji group of islands).

I would have fixed these errors except that I don't know how to move a
country.

Any suggestions on how to fix this?



2009/4/2 Iván Sánchez Ortega <ivan at sanchezortega.es>:
> El Miércoles, 1 de Abril de 2009, Randy George escribió:
>>  I also checked against Google Earth by locating  LL -155.136552,
19.68534
>> on OSM and on GE. GE shows this point at the road intersection of Akolea
Rd
>> and Kaumana Dr, while in OSM it's shifted off the road?
>>
>> I assume I am doing something irregular. Are the OSM tiles
>> sphericalmercator EPSG:900913? Or some other EPSG?
>
> Yeah, OSM uses 900913 for rendering. Internally (for editing) it uses
> unprojected WGS84 (AKA EPSG:4326).
>
>
> Maybe the OSM data for that zone is just wrong (badly surveyed, maybe?)
and
> needs to be fixed. Have you checked (with a GPS) that zone?
>
>
> Cheers,
> --
> ----------------------------------
> Iván Sánchez Ortega <ivan at sanchezortega.es>
>
> Un ordenador no es un televisor ni un microondas, es una herramienta
compleja.
>
> _______________________________________________
> newbies mailing list
> newbies at openstreetmap.org
> http://lists.openstreetmap.org/listinfo/newbies
>
>

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