[Qgis-user] to line or not to line

[Gerhardus Geldenhuis]

Hi
Many thanks for all the answers! I am doing a line and a polygon for my map.

Best Regards

On Sat, Oct 29, 2011 at 7:51 PM, Anita Graser <anitagraser at gmx.at> wrote:

> Hi Gerhardus,
>
> The common approach I saw most of the time is to have a polygon layer that
> traces the form of the river banks and a line layer that contains the river
> center line and can be used to calculate distances easily.
>
> Best wishes,
>
> Anita
>
> On Sat, Oct 29, 2011 at 7:50 PM, Gerhardus Geldenhuis <
> gerhardus.geldenhuis at gmail.com> wrote:
>
>> Hi
>> This question is not as much QGIS specific but more about generic GIS
>> concepts.
>>
>> In all of the tutorials I have watched so far rivers is represented as
>> lines. This makes sense and if you were to do later analysis I would imagine
>> a line would make it easier to get information like the length of all rivers
>> in an area. However rivers do not play nice and have varying widths. I could
>> adjust the line width but that would only be accurate for a certain part of
>> the river. My question is thus how do you represent a river of any feature
>> for that matter, of varying width and substantial length. If the river is a
>> polygon then I would loose the ability to extract length data or is that
>> assumption wrong? Do I represent a river/feature as both a line and a
>> polygon then?
>>
>> Regards
>>
>> --
>> Gerhardus Geldenhuis
>>
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>>
>>
>


-- 
Gerhardus Geldenhuis
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