[postgis-users] Using a buffer with a LineString covering the whole world

[Chris Hermansen]

You ARE a feisty thang these days, aren't you :-)

Paul Ramsey wrote:
> If he's just buffering one line, he should calculate it by hand, like
> a Real Man :)
>
> On Wed, Feb 11, 2009 at 10:22 AM, Chris Hermansen
> <chris.hermansen at timberline.ca> wrote:
>   
>> It might not be that bad, Paul, depending on the latitude of the start
>> and end points, which - USA <-> France - sounds like they might be
>> pretty close.  If it was say Seattle Paris, that would be ok.
>>
>> Paul Ramsey wrote:
>>     
>>> that's really not a good option. mercator does not preserve
>>> length/distance, so the buffer would end up larger at one end than the
>>> other, and furthermore would not be the expected width, since it would
>>> be built far from the latitude of true scale.
>>>
>>> P.
>>>
>>> On Wed, Feb 11, 2009 at 8:52 AM, Pavel Iacovlev
>>> <iacovlev.pavel at gmail.com> wrote:
>>>
>>>       
>>>> As an option you can use google mercator projection for the whole world. But
>>>> read carefully docs about it to understand the precision loss.
>>>>
>>>> http://genuchten.blogspot.com/2008/04/srid-stuff-in-postgis.html would be a
>>>> good start.
>>>>
>>>> On Wed, Feb 11, 2009 at 6:26 PM, Matthes Rieke <matthes.rieke.01 at gmail.com>
>>>> wrote:
>>>>
>>>>         
>>>>> Hi all,
>>>>>
>>>>> I am currently running into this problem: I have a LineString in lat/long
>>>>> coordinates (SRID 4326 - going from USA to france). I now want to create a
>>>>> buffer in meters from this. So the normal way to transfrom the coordinates
>>>>> to a planar CRS, buffering, then transforming back to 4326 does not work
>>>>> (the Line is covering many UTM zones). What would be a reasonable solution
>>>>> for this problem?
>>>>>
>>>>> Thanks and regards,
>>>>> Matthes
>>>>>
>>>>> _______________________________________________
>>>>> postgis-users mailing list
>>>>> postgis-users at postgis.refractions.net
>>>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>>>>
>>>>>
>>>>>           
>>>> --
>>>> http://iap.md, The future is open
>>>>
>>>> _______________________________________________
>>>> postgis-users mailing list
>>>> postgis-users at postgis.refractions.net
>>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>>>
>>>>
>>>>
>>>>         
>>> _______________________________________________
>>> postgis-users mailing list
>>> postgis-users at postgis.refractions.net
>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>>
>>>       
>> --
>> Regards,
>>
>> Chris Hermansen         mailto:chris.hermansen at timberline.ca
>> tel+1.604.714.2878 · fax+1.604.733.0631 · mob+1.778.232.0644
>> Timberline Natural Resource Group · http://www.timberline.ca
>> 401 · 958 West 8th Avenue  · Vancouver BC · Canada · V5Z 1E5
>>
>> _______________________________________________
>> postgis-users mailing list
>> postgis-users at postgis.refractions.net
>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>
>>     
> _______________________________________________
> postgis-users mailing list
> postgis-users at postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-users
>   


-- 
Regards,

Chris Hermansen         mailto:chris.hermansen at timberline.ca
tel+1.604.714.2878 · fax+1.604.733.0631 · mob+1.778.232.0644
Timberline Natural Resource Group · http://www.timberline.ca
401 · 958 West 8th Avenue  · Vancouver BC · Canada · V5Z 1E5