Topology describes non-metric relationships among geometric figures, such as adjacency, containment, and orientation.
7
votes
2answers
923 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.
...
9
votes
4answers
2k views
Remove Duplicate Polygons Using Open Source Tools
I have a shapefile containing features with duplicate geometries, but different attributes (e.g. a polygon with attribute XX, and an identical polygon with attribute XY). I want to identify the ...
13
votes
1answer
579 views
Identifying topological relationships using PostGIS
I'm trying to perform a basic typology analysis using PostGIS. My objective is to find any polygons that touch other polygons. To do this, I thought the ST_GetFaceEdges would work
(reference). I want ...
6
votes
5answers
1k views
How to convert line simple features to topological network?
using Gdal/ OGR is there a way to convert a shp, kml, or PostGIS line layer into a network of nodes and segments so it can be used in packages such as networkx?
17
votes
2answers
1k views
What are the benefits of Multipart Features?
Multipart points, lines, and polygons are implemented in nearly every GIS, but what benefits, if any, do they provide?
In a relational database attributes shared by different features can be stored ...
10
votes
3answers
571 views
Efficiently finding the 1st order neighbors of 200k polygons
For every one of the 208,781 Census block groups, I'd like to retrieve the FIPS IDs of all of its 1st order neighbors. I have all the TIGER boundaries downloaded and merged into a single 1GB ...
4
votes
2answers
383 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
723 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
2answers
799 views
How to repair topology of a shapefile?
I performed an object-based image analysis using ENVI EX, and each of the classified features were exported as a shapefile. I transferred those shapefiles into ArcMap 10, and tried to intersect them ...
6
votes
3answers
1k views
Create features from ArcGIS Topology errors
I have imported field users shapefiles into an ESRI geodatabase so that I can create some topology rulesets that identifies the errors as needed. Unfortunately the field users do not have a license ...
1
vote
1answer
526 views
ArcGIS topology rules file (.rul)
Has anyone converted ESRI's topology rules file (.rul) into another format? I built a complex topology rules set and would like to QC it in something easier to read and work with than ArcCatalog. A ...
3
votes
2answers
323 views
Topology error in ArcGIS for SDE 10. “Cannot create topology”
When trying to create a topology for a polygon feature class in ArcSDE. I right click the feature dataset that the feature class resides and try to create a new topology. I get an error saying, "The ...
3
votes
2answers
269 views
Getting line FID from polygon ITopologyGraph
I want to export polygon Arc list to txt file for that
I created topologygraph for personal geodatabase feature class (polygon)
using ITopologyGraph::build.
I got polygon FIDs but I am not getting ...
