Skip to content


Added test and sample wkt to replicate issue 4189
Browse files Browse the repository at this point in the history
  • Loading branch information
timlinux committed Oct 10, 2012
1 parent 3d79a0b commit 0617992
Show file tree
Hide file tree
Showing 4 changed files with 55 additions and 1 deletion.
7 changes: 7 additions & 0 deletions tests/src/python/.idea/other.xml

Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.

8 changes: 8 additions & 0 deletions tests/src/python/.idea/testrunner.xml

Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.

40 changes: 39 additions & 1 deletion tests/src/python/
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'

import os
from qgis.core import (QgsGeometry,
Expand All @@ -20,7 +21,9 @@

from utilities import (getQgisTestApp,
# Convenience instances in case you may need them
# not used in this test

Expand Down Expand Up @@ -202,6 +205,41 @@ def testCrosses(self):
("True", crossesGeom))
assert crossesGeom == True, myMessage

def testSimplifyIssue4189(self):
"""Test we can simplify a complex geometry.
Note: there is a ticket related to this issue here:
Backstory: Ole Nielson pointed out an issue to me
(Tim Sutton) where simplify ftools was dropping
features. This test replicates that issues.
Interestingly we could replicate the issue in PostGIS too:
- doing straight simplify returned no feature
- transforming to UTM49, then simplify with e.g. 200 threshold is ok
- as above with 500 threshold drops the feature
pgsql2shp -f /tmp/dissolve500.shp gis 'select *,
transform(simplify(transform(geom,32649),500), 4326) as
simplegeom from dissolve;'
myWKTFile = file(os.path.join(unitTestDataPath('wkt'),
'simplify_error.wkt'), 'rt')
myWKT = myWKTFile.readline()
print myWKT
myGeometry = QgsGeometry().fromWkt(myWKT)
assert myGeometry is not None
myStartLength = len(myWKT)
myTolerance = 0.00001
mySimpleGeometry = myGeometry.simplify(myTolerance)
myEndLength = len(mySimpleGeometry.exportToWkt())
myMessage = 'Before simplify: %i\nAfter simplify: %i\n : Tolerance %e' % (
myStartLength, myEndLength, myTolerance)
myMinimumLength = len('POLYGON(())')
assert myEndLength > myMinimumLength, myMessage

if __name__ == '__main__':
Expand Down

0 comments on commit 0617992

Please sign in to comment.