All Questions
22 questions
0
votes
0
answers
29
views
Extract a hierarchical topology from stream network
A typical stream network has a hierarchical topology that resembles a cladogram (phylogenetic tree). There are many software tools that have been developed to analyze variables along a cladogram, ...
- 9
0
votes
1
answer
71
views
Node information in a PostGIS dataset
I am working in QGIS / PostGIS to plan the cable layout for a seismic array. The power distribution is from the green point with the white cross in the middle. The nine green points marked with a ...
- 3,836
0
votes
1
answer
57
views
ArcGIS Pro - routing, remove short network elements and reconnect edges
I am setting up an ArcGIS Pro network for use in Network Analyst. So far things work pretty well, depart from some 1600 errors due to this kind of problem: "
SourceName: linknetz, ObjectID: ...
- 948
1
vote
0
answers
233
views
Split intersections of lines considering bridges and tunnels
I want to make a road network routable. I already have a road shapefile, but there are many intersections of lines that I want to split. Now I have two problems:
(1) My first approach to split them ...
- 179
1
vote
1
answer
362
views
Snapping two topology layers together based on point
In QGIS 3.14.15 with GRASS 7.8.3 I have two layers both with correct topology that function how they should. When using the Network Analysis > Service Area tool, they work as they are supposed to. ...
4
votes
2
answers
422
views
Generate points along branching lines
I am looking to generate points along a series of connected lines at regular intervals, but I wish to keep this interval even when a line is branching into 2 or 3 other lines. All the regular tools I ...
3
votes
0
answers
364
views
Dealing with bridges over roads in PostGIS topology?
first time posting please ask for more details if not enough provided.
I am using OSM road data and have created postgres topology for them. I am now cleaning up the data before exporting it for ...
- 31
2
votes
0
answers
1k
views
Topology Network in PostGIS database
I'm returning to the same question all over again. I'm dealing with electrical network and I'd like to build topology for all network lines in database so I can construct nodes and edges dynamicly for ...
- 571
6
votes
2
answers
1k
views
Dragging all vertices at a given point programmatically in PyQGIS
I'm writing a Plugin where you build networks with point and line geometries. One Tool should give the User the possibility to make changes to the network by dragging and dropping the points to ...
- 109
0
votes
1
answer
561
views
Identifying road segments completely cut off by polygon using QGIS?
I have a road network (black line) and I want to identify all segments that are completely cut off by my flood polygon (blue polygon).
I have clipped the road network to get all roads within the road ...
- 823
2
votes
1
answer
650
views
Correcting topology error in PostGIS?
I am interested in tools to correct topology errors in PostGIS, focussing on road networks. Is there a tool that corrects topology errors automatically, so that I can use the network for routing?
I ...
- 3,440
6
votes
1
answer
128
views
Restricting the creation of lines for network creation in QGIS: start/end vertices must snap to existing vertices
My interest lies in network creation, however, knowing how to do that in general would be a plus. How is it possible to prevent a user from creating a line (line vector) without connecting it ...
- 1,852
2
votes
1
answer
321
views
How to solve "features were not reachable" warning message using v.net.distance in GRASS
I'm using GRASS 7.0.4 under Linuxmint 17.1 KDE.
I need to build a raster with the shortest distance from every pixel to a city following a road. I have two shape files, the city (point) and the road (...
- 193
1
vote
0
answers
799
views
Removing pseudo-nodes using QGIS Sextante plugin?
I have a road network (vector) that i'm interested in carrying out some space syntax analysis on.
Predictably my GIS data is in a pretty terrible state. For example, there are a bunch of roads on the ...
- 559
1
vote
1
answer
115
views
Setting junction properties in ArcGIS Desktop?
I have a situation where I have a line feature class and need to build a network out of it. The lines represent roads.
I wonder how I can model the intersections on the network. Almost all of them ...
- 629
1
vote
1
answer
208
views
Grass GIS "v.in.ogr": How to prevent crossing lines from beeing split where they don't share a common node?
I want to import a road network into grass gis to run network analyses. I use "v.in.ogr" to import my road shapefile. The problem is that Grass GIS seems to split every crossing line no matter if they ...
- 1,958
4
votes
1
answer
1k
views
PostGIS table to network analysis
I use PostGIS 2.0 and Python API (GeoAlchemy) to work with it.
I want to convert topological informations (points, lines, faces) from PostGIS tables to topological network (points, lines) to study it ...
- 61
5
votes
2
answers
3k
views
How do you remove isolated roads from a bigger network?
I'm trying to perform an OD Cost Matrix calculation on a set of points using a road network from OpenStreetMap data. The network contains lots of roads that don't connect to the rest of the network. ...
- 271
2
votes
1
answer
444
views
ArcView: Trim polyline, that is shorter than specific dangle length (alternative to tool: Trim Line)?
I am looking for a way to trim dangles from a polyline shape, that are shorter than a specific length like the Trim Line Tool for ArcEditor and ArcInfo, but with ArcView-License.
I already discover, ...
- 148
5
votes
1
answer
1k
views
Road topology problem solution for junction
I am working with a Road Network. I have digitized the lines with AutoCAD Map 3D. Then Imported it to ArcMap. After entering all kind of database I have created Routing Dataset. Unfortunately it's ...
- 3,217
2
votes
1
answer
3k
views
How to populate From Node and To Node fields for a polyline feature class? (ArcGIS 10)
I need to populate FNODE and TNODE fields for my roads dataset. I have an intersections point feature class that has unique ids, and I need each road segment to have an FNODE and TNODE value that ...
- 7,403
17
votes
4
answers
5k
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 ...
- 5,618