[QGIS-Developer] Split parts tool creates invalid polygons

[Raymond Nijssen]

Hi Anita,

Tried what you said but cannot reproduce it. This might depend a lot on 
what shape you draw and how/where you cut it. What does your validation 
error say?

I got this:


Processing algorithm...
Algorithm 'Check validity' starting...
Input parameters:
{ 'INVALID_OUTPUT' : 'memory:', 'VALID_OUTPUT' : 'memory:', 
'INPUT_LAYER' : 
'MultiPolygon?crs=EPSG:4326&uid={03c00bda-6d88-43b9-99cd-504f439fcfb5}', 
'ERROR_OUTPUT' : 'memory:', 'METHOD' : 2 }

Execution completed in 0.12 seconds
Results:
{'ERROR_COUNT': 0, 'ERROR_OUTPUT': 
'output_d1f8c9fc_61da_455a_afe3_a5e4692bef9d', 'INVALID_COUNT': 0, 
'INVALID_OUTPUT': 'output_67acdd34_cf81_4515_8088_ba5b03820c57', 
'VALID_COUNT': 1, 'VALID_OUTPUT': 
'output_a11e2f0a_cfa8_46a2_9336_b206765f1890'}

Loading resulting layers
Algorithm 'Check validity' finished



Regards,
Raymond



On 13-02-18 21:50, Nyall Dawson wrote:
> On 14 February 2018 at 06:44, Anita Graser <anitagraser at gmx.at> wrote:
>> Hi,
>>
>> The split parts tool creates invalid polygons according to GEOS check
>> validity. This issue seems to have been discussed two years ago
>> https://issues.qgis.org/issues/12799 but it still persists today in master.
>>
>> To reproduce:
>> 1. Create a memory layer with multipolygon type
>> 2. Add a polygon
>> 3. Split the polygon using split parts
>> 4. Use the vertex tool to move the parts apart, in order to avoid issues
>> with polygon parts sharing an edge or vertex
>> 5. Run check validity
>>
> 
> Can you please share before/after WKT for the geometries?
> 
> Nyall
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