Topology describes non-metric relationships among geometric figures, such as adjacency, containment, and orientation. It is a branch of Mathematics, which deals in geometry without measurement.

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538 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. But unfortunately its ...
2
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1answer
62 views

Snapping leaves small gap between features in ArcGIS for Desktop?

I'm using classic snapping in ArcGIS 10.1. At the scale (1:5,000) that I'm using to snap the edge of one rectangular feature to the edge of another rectangular feature, snapping seems to work fine. ...
2
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1answer
476 views

JTS - Java Topology Suite - Calculate radius from a given point

From point A, I want to check if a point B is within a certain radius from A. How calculate it usindo JTS? I tried this: Coordinate posicaoAtual = new Coordinate(-12.974900375893823, ...
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1answer
41 views

Orphan road segments

I am working with OSM road data for a developing nation. Included in the dataset are various small networks of roads that are orphans or islands i.e. not connected to the main road network. For ...
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1answer
65 views

Is there any topology handler in QGIS?

When importing autocad maps, sometimes topology will be chaos, this need to be amended. And when I add new topology in QGIS, how to save that to the postgreSQL? Is these functions included in QGIS or ...
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1answer
72 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 ...
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1answer
285 views

How to interact with GRASS GIS vector map topology “level/layers” from terminal/command line?

Is there anybody out there that can maybe assist in the most simplest form of code to call on command line to "export topology" (which is level 2 information in GRASS) as separate spatial data, as ...
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1answer
50 views

Using topology to connect nodes <100m apart only

I have a bunch of line segments, most of which have gaps that are 100m or less. What I'm trying to do is connect these gaps so I have a series of connected line segments BUT leave nodes that are over ...
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1answer
44 views

In ArcGIS 10 - how do I clip an arc

I have an arc that has violated the topology rule that the road feature should not extent outside of my boundary. I tried to use the clip tool in editor but cannot complete the clip. I should be able ...
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1answer
35 views

Enabling: Raster and Topology

I'm new to GIS and tile servers. I've installed TinyOWS pretty successfully except for what looks like to be some dependency issues. I have installed PostGIS and also PostgreSQL. PostGIS is supposed ...
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307 views

How to create a topologically correct dataset in PostGIS (with GRASS)?

I have shapefiles which I have loaded in postgis and now i am trying to use geometric function in postgis like ST_intersect and they fail because the data is not topological correct. I have tried to ...
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158 views

Joining layers with respective elements with PostGIS Topology

Recently I have started using PostGIS topology extension, but I have some difficulties in understanding how the structure works: One of the key points is the use of "layer"s: as of what I understand, ...
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90 views

Topology validate error

Im using Arcmap 10.1 version.I don't know where i made mistake my database. I have attached an example image to show the Error Report.
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72 views

Polygon Layer Cleaning with QGIS

I have a little situation with my data. I have vectorized a raster layer, and now I have some issues with the geometries, as you can see in the picture. Most of errors I have are like this one. ...
2
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0answers
296 views

Remove pseudo nodes in QGIS

I have a shapefile of city streets. I tried to run the Road Graph tool on them but the select box does not populate with the layer. I ran the Topology Checker on the layer and found that there are ...
2
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0answers
93 views

Is there a way to build topology and work with topology relations in PyQGIS?

Is there a way to build topology and work with topology relations in PyQGIS? I'm asking because I need to run some custom generalization algorithms on my data, and I need to preserve topology. ...
2
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0answers
119 views

Is the TIN created out of several cross sections different from merging the TINs created out of each set of two cross sections?

I have a river with cross sections that have the water surface elevation values. I am trying to create TIN from the water surface values and then compare it with the topo (to see the flooded areas). I ...
2
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0answers
261 views

GeoDatabase topology and rules with a *.rul file

I have been working for some time on a solution to a problem much like this question. I have several layers that I want to resolve together. I have them all in topology (geodatabase) and have been ...
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0answers
350 views

Snapping line endpoints to a point feature class by adding a vertex

I have a line feature class whose endpoints should snap to the closest point in a points feature class. The problem is, I do not want the lines to move, but rather a vertex must be added to the ...
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25 views

how to create Topology table?

i have gis database called Madar in pgadmin with postgis and pgrouting extension, all the data inside gis database already inserted by shp2postgre tool , what i really need now is how to make topology ...
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0answers
52 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 ...
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0answers
58 views

Topology in Arcgis and QGIS

I have been studying topological methods like 4 intersection , 9 intersection, dimension extended and CBM (calculus based methods) like RCC-8. I want to know which of this method is used for ...
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0answers
68 views

Metric maps vs topological maps for path finding and UI rendering of indoor floor layouts

I'm building a software to map indoor floor plans of large facilities (like malls). I read through some of the questions on this forum, but my constraints are a little different than the ones ...
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89 views

QGIS Topology checker wrong results?

I am trying to understand topology checker results and frankly i dont get it - probably i am doing something wrong. Source - Point layer Target - Polygon layer Must be inside - that is working as ...
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53 views

ArcGIS planarize vs autofixing “must not intersect or touch interior” topology

trying to fix topology errors in OSM here. I am wondering whether ArcGIS planarize is essentially the same as creating a topology that says a class must not intersect or touch interior. Then ...
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70 views

vb.net arcobjects validate topology function only works after I use arcmap topology tool validate topology first

I find a strange thing occasionally, I have a validate topology function developed by vb.net arcobjects. It work not properly. The case is: open arcmap start editing use my validate topology ...
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30 views

How can I associate a consistent polygon area with a set of attributes using a topology?

Consider the following topology. SELECT CreateTopology('topotestschema', 0, 0.01); CREATE TABLE topotest (id SERIAL PRIMARY KEY, data TEXT); SELECT AddTopoGeometryColumn('topotestschema', 'public', ...
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0answers
29 views

vb.net arcobjects “current no topology available”

I am using ArcMap add-in to perform a topology validation. I have defined a topology in the geodatabase and add it in ArcMap TOC. When I try to get the current topology using ArcObjects, I get this ...
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87 views

v.clean in QGIS Python console

I have tried to use v.clean and v.clean.advanced (by GRASS GIS) within a script in QGIS, and was not able. I followed instructions here:, but was not able to do so. I got message: "No module named ...
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0answers
78 views

Batch Clip (Editing Session)

I'm trying to correct some topology errors in my geodatabase, now focusing on two feature classes: grass and buildings. They must not overlap. However, there are plenty of spaces where the grass was ...
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0answers
187 views

How to simplify a self intersected / self overlapped polyline using ArcObjects?

I have a self intersected polyline, how can I break it into 5 records stored in the same table using arcobjects? (splited by vertices and the intersection point) Here is what I have got and it ...
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0answers
148 views

How can I edit spatial data automatically on postgis and check for topology errors on said data whitout using shapefiles?

So, I have spatial data stored in postgis (points, lines and polygons) and would like to edit and update those in an Open Source software (quantum GIS, grass, etc.) to check for topologic errors, ...
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288 views

Vertex and Nodes Tool - Migrating from 9.3.1 to 10.2.1

A previous employee built a custom tool for users in our organization that displays nodes and vertices when editing. Essentially the purpose is: The Display Topology Nodes button will symbolize the ...
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57 views

Delete polygon underlap?

I am editing a layer in QGIS with severe polygon overlaps. Is there a way to delete the underlapping portions (i.e. the invisible parts) using QGIS? If I import the layer into GRASS using the ...
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0answers
43 views

QGIS : copy/paste with “Avoid Intersection” option

I need to copy and paste polygons from one layer to another but with adjustments in the pasted geometries: I need them to be cut in the same way they would have been cut by a single edit with the ...
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0answers
82 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
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0answers
350 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 ...
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0answers
99 views

From classified image to topology in ArcInfo

I have some coastal 4 band imagery that I have classified to designate land, water, and undetermined. I want to convert this to polygons with topology, and significantly simplify the polygons. If I ...
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0answers
271 views

topology rules for structuring topology data to get line feature as topoparent in topology graph

i Created topology graph of a polygon feature and i copied geometry of topology edges into line feature class,and topology nodes into point feature class i created topology layer containing ...
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0answers
34 views

Invalid Topology/Topoengine error: Intersect and Clip

I have a large, provincial extent gdb file with numerous detailed polygons (representing roads, buildings, forest cover, etc), and want to clip this layer to about 700 unique polygons, some of which ...
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32 views

QGIS topology overlap check

I have checked topology rule must not overlap with and i get error The problem is that i have check this many times, and made hole vertex after vertex so it is not possible that these objects ...
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0answers
37 views

How to identify Topology Exception

Anyone have any innovative way(s) of "quickly" marking topology exceptions. I have ~300,000 bridges which have pseudo nodes located on either side of the bridges where the bridge and road endnotes ...
0
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0answers
149 views

Grass Processing tools via QGIS : v.clean snap, chdangle, and rmdangle

Using QGIS 2.6 Grass Processing tools, I'm trying to clean up topology on a water network layer. I noticed topological errors when first trying to break all lines on intersections using v.clean break. ...
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0answers
65 views

Any way to speed up my postgis topology creation?

I need to do topology aware simplification, and I'm investigating PostGIS's new topology extension. However it's taking a very long time to create the topology, and I'd like to know if there's ...
0
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0answers
32 views

GRASS: How to remove several categories from a geometry?

I am totally new to GRASS (and have found it difficult to get into that way of thinking and its terminology). I use grass70 under Ubuntu 14.04. I have the following problem which I have tried to ...
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0answers
518 views

Intersection postgis TopologyException

I'm trying to make a quite simple analysis in Postgis, but I'm finding some problems. I want to in the first place create buffers for then, intersects themselves but one, this will be differenced. ...
0
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0answers
39 views

Can arcobjects validate topology globally

I want to develop a function which allow user to validate a topology in the whole map wide. But from what I searching from internet, to validate a topology, a dirty area (polygon) must be defined, ...
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0answers
105 views

Dissolve a Geometric Network in ArcGIS

I have a geometric network of water mains in ArcGIS. It it composed of a line feature class. I would like to dissolve it based on whether line segments share common endpoints only. So basically ...
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0answers
48 views

The topology cannot be validated because it is checked out

when I try to validate an existing topologiy in my personal GDB I got this error "the topology cannot be validated because it is checked out". How to solve it? thanks! It is a personal GDB. I'm ...
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46 views

Why would this script only load 14 out of ~13,000 feature classes to the topology?

The following script adds ~13,000 feature classes in a gdb into an existing topology. If I want to add rules to said topology, would I write a second script or include it within this script below? ...