.... However, in this case, I think you can estimate a (maxima) scale
based at the minimo detail that you can finding in the vector layer and
in the permitted error.
The permitted error it's based in the average minimo detail that human
eye can perceive. It's estimated in 0.2 mm, so you can use this relation:
1 lenght in papper
---------- = -----------------------
scale length in reality
Lenght in papper is 0.2 mm. If your permitted error is 10 metres (10000
mm), then:
scale = 10000 / 0.2 = 50000
This is in theory. Reality is that error can be (is in fact) greater
depending on method for get the vector layer. For example, a lines layer
from a navigator GPS has an error of .... 20 m, then this layer has a
maxima util scale of 1 : 100 000. You can use for other minor scales (1:
200 000 ; 1 250 000; etc) with good precission, but not for 1:50 000, or
higher.
Good luck
Carlos Cerdán
El 10/08/13 05:10, Nick Hopton escribió:
Luisa Peña wrote
Dear all,
I have a vector (in ESRI Shapefile) and I wanted to know what is its scale
of oproduction (1:1000 or 1:100000 or something) since I have no
associated
metada.
Thanks
Luisa
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Hi Luisa, shapefiles don't have a 'scale' as such, you can render them in
QGIS at any scale that produces the result you are looking for, but it's for
you to set the scale for the project. For example, a lot of the shapefiles I
use render well at a scale of 1:25000 but in most cases I can also use them
at scales of say 1:10000 or 1:50000.
N.
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