[Qgis-user] [Qgis-developer] About a 'directed' LINESTRING (e.g. for oneway streets)?

[Anita Graser]

Hi Stefan,

Nathan developed the line direction switcher  
http://gis.stackexchange.com/questions/9261/how-can-i-switch-line-direction-in-qgis

I do a lot of work with street networks where line direction is very  
important. So far, I haven't run into any problems due to the direction  
being messed up by any tools.

Best wishes,
Anita



Am 01.09.2013, 15:43 Uhr, schrieb Stefan Keller <sfkeller at gmail.com>:

> Hi Alexandre
>
> Thanks for the quick answer and the hint to the plugin LineSwitch (from
> Underdark?).
> Besides that the plugin page is'nt online currently for me - I'd like to
> emphasize that my main question is about the reliability through all
> processing steps to maintain the direction.
> I actually want to hear if anybody had issues when importing/exporting
> directed lines with OGR or analysing them with fTools or Sextante.
>
> Yours, Stefan
>
>
> 2013/9/1 Alexandre Neto <senhor.neto at gmail.com>
>
>> Linestrings have a direction already, you can use marker lines with  
>> arrows
>> to represent the original direction. For analysis you can revert the
>> polyline direction using it's attributes, or using the switch the  
>> direction
>> of polyline plugin [1] to actually invert vertex order.
>>
>> Alexandre Neto
>>
>>
>> [1] http://plugins.qgis.org/plugins/lineswitch/
>>
>>
>> On Sun, Sep 1, 2013 at 1:53 PM, Stefan Keller <sfkeller at gmail.com>  
>> wrote:
>>
>>> I'm designing a spatial database and like to introduce a LINESTRING  
>>> where
>>> the direction is important, e.g. to describe a oneway street or a water
>>> pipe. I indicate this by another attribute, e.g. "direction: BOOLEAN",  
>>> or
>>> "direction: ENUM(both, as_is, reverse)
>>>
>>> A "directed line" means that the order of the coordinates of a  
>>> linestring
>>> value is important - like in a directed graph - and needs to remain the
>>> same whatever happens to it e.g. when importing, storing, retrieving,
>>> analysing or rendering...
>>>
>>> Does anybody have had any issues to manage "directed lines" in QGIS  
>>> (OGR,
>>> extensions, etc.)?
>>>
>>> Yours, Stefan
>>>
>>>
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>>>
>>