[Qgis-user] Simplify?

[Chris Green]

Hi Ramon

 

I have been trying to modify the original shape file rather than save to a new file. When I tried selecting the ‘save to a new file’ option , the message after simplification said 

 

‘There were 3638321 vertices in original dataset which were reduced to 3638321 vertices after simplification’

 

In other words, no simplification at all. I suspect that this is actually what is happening when I try to over-write the existing file – it indicates that simplification took place but actually what is saved is identical to the original.

 

Thanks anyway…..

 

 

Chris  

 

From: qgis-user-bounces at lists.osgeo.org [mailto:qgis-user-bounces at lists.osgeo.org] On Behalf Of Ramon Andiñach
Sent: 11 November 2011 13:19
To: <qgis-user at lists.osgeo.org>
Subject: Re: [Qgis-user] Simplify?

 

 

On 11/11/2011, at 20:40, "Chris Green" <chris.green at ibstv.co.uk> wrote:

Hello

 

I am using QGIS 1.7 in a Windows 7 environment. Everything seems great except for the simplify function (Vector->Geometry Tools->Simplify Geometries)

 

I am trying to simplify an ESRI shape file which is around 95M. I have tried various tolerance settings, but although it looks like some simplification is taking place, actually the file is unchanged. So for example with tolerance setting of 1.0 I get an encouraging message that says:

 

‘There were 3638321 vertices in original dataset which were reduced to 559351 vertices after simplification’

 

However after saving the changes to the layer, the dataset still looks identical to the un-simplified version and the file size remains unchanged at 95M. I have tried to simplify smaller shape files also, but with the same result. 

 

Can someone tell me what I am I doing wrong?

 

 

Hi Chris,

This is a guess...

 

I suppose your output file is different to your input file?

 

(otherwise windows will probably get confused)



-ramon.

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