Tagged Questions
2
votes
3answers
105 views
How to clean layers from non topological databases?
I'm doing my internship in a consulting office which is switching from MapInfo to QGIS/GRASS 1.8.0.
I posted here a few days ago about the way to clean a polyline from a Lidar data with v.clean.
...
4
votes
1answer
117 views
How to repair and clean contours from high data resolution (lidar)?
I'm unsuccessfully trying to make a bathymetric map with contours extracted from Lidar data at 1 m resolution.
The extracted contours have a lot of artifacts like dangles and islands.
First I used ...
1
vote
0answers
42 views
How do you split a feature using an existing line in QGIS?
All,
Is there a way to split a feature (polygon) using an existing line (selected polyline) in QGIS?
Thanks!
-m
1
vote
1answer
98 views
Grass v.clean.snap with Polygons
I am doing some topology testing using Grass in QGIS. I am hoping to snap nodes to eliminate gaps between polygons. When I use the v.clean.snap function in Grass it does not work on polygons. When I ...
2
votes
0answers
116 views
Topology problems with QGIS/GRASS
*edited file links below
I'm working on several NGO projects at the moment, all of which are reliant on being able to use a district level map with some 490+ features, and I am running into some ...
2
votes
4answers
134 views
How can I create polygons of the area surrounded by roads / lines?
I'm currently trying to create polygons that represent the areas surrounded by roads. The roads are stored in PostGIS as points / lines so I have flexibility over what I can do with them.
I'm ...
1
vote
0answers
81 views
How to handle/ avoid intersect errors when clipping the difference between two layers?
Using QGIS + Grass, I've added a shapefile of coastline and islands to my map.
I then buffer this shapefile to create a coastal zone of a known width. At this stage the buffer consists of the ...
7
votes
2answers
917 views
How to check Topology in QGIS?
I have two Shapefiles with Polygons ( City and Forerst)
Is there a Plugin who is able check the topology (QGIS)? Like "Knots do not overlap" or something like that? I dont want that they overlap.
...
4
votes
2answers
382 views
Snapping two polygons together
I have a problem with two vector layers, both polygons. I have been digitising an historical map which contains large areas called townlands, filled by smaller areas called fields. I digitised both as ...
12
votes
2answers
720 views
How to generalize a polygon file and maintain topology in QGIS?
my problem: I have a polygon-file in shape-format, which I need to generalize. How can "split" the polygons into lines, generalize and than "rebuild" the polygons, so that I can ensure, that there are ...
2
votes
1answer
468 views
How do I subdivide and edit polygons preserving topology?
I'm using QGIS. I have a layer made up of many adjacent polygons - let's call them "countries". I currently use the Atlas plugin to export each "country" polygon to a .png file.
I want to further ...
9
votes
3answers
1k views
How to connect lines in a network?
I have a shapefile of lines and another of polygons. When two or more lines intersect a polygon they should be connected (snapped), but sometimes during manual digitization this doesn't occur. I need ...
16
votes
1answer
865 views
What's the status of Postgis 2.0 topology support in QGIS?
Having followed the Postgis developments over the past 6 months I have noticed a bunch of features which seem to be incredibly cool especially in the area of topologies and associating calculations on ...
