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.

learn more… | top users | synonyms

1
vote
3answers
144 views

Automatically add vertex to polygon where vertex of another polygon touches it?

The polygons that I use in ArcMap 10.2 are drawn so that they snap to each other, but never overlap. I've described a general case in the following image: A polygon is defined by the minimum ...
2
votes
1answer
54 views

How to suppress polygon boundaries shared by objects of same type in QGIS?

Given polygons - like landcover in OpenStreetMap or street areas in cadastre - how can one suppress those polygon boundaries which are shared by objects (features) of same type in QGIS (see figure ...
0
votes
1answer
30 views

Simplifying polygons in ArcGIS considering contains-one-point topology rule?

I want to simplify polygons using the "Simplify Polygon (Cartography)" tool in ArcGIS 10.2. Additionaly there is one point in each polygon and this condition should still be fulfilled after ...
1
vote
1answer
54 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 ...
2
votes
1answer
65 views

How do I save topology errors in QGIS?

I'm currently doing a project on finding blocked roads in a road network layer. I've figured that I can use the topology checker with the rule 'must not have dangles' and find them this way. But I ...
1
vote
0answers
45 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 ...
2
votes
0answers
48 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. ...
3
votes
1answer
63 views

How to connect lines with gaps to continuous line?

and I have a lot of this problem like in image. The two line are separated but i want a continuous line. What rule should I choose in Topology Checker? I want to know all the separated line, so i can ...
0
votes
1answer
79 views

Polygon intersection with LineString in PostGis

I have a table which contains GPS coordinates at certain times. I created a LINESTRING from them ordered from the oldest to newest. I also have a POLYGON and I would like to determine the subset of ...
1
vote
2answers
37 views

Splitting polgons in QGIS produces topology errors

I am trying to split existing polygons but when I do, gaps and overlaps are created between the polygon I am cutting and adjacent polygons. I have snapping switched on and have enabled topological ...
2
votes
1answer
44 views

Editing polygons simultaneously in ArcMap?

I have two polygons: How can I reshape both Polygon 1 and Polygon 2 at the same time? Will the area of each polygon change automatically in the table after reshaping? I'm using ArcMap 10.1.
2
votes
1answer
30 views

Topology Editing using ArcView (now called Basic) license level of ArcGIS Desktop?

I am building a geodatabase from data collected on a GPS handheld in the field. The GPS device collects decently accurate information but I need to make sure all the polygons, lines, and points are ...
2
votes
2answers
61 views

What is the difference between Intersect & Overlap in ArcGIS Server?

When you run a Query Task on the ArcGIS Server's REST Endpoint, you need to give a spatialRel There are two spatial relationships which are quite similar: esriSpatialRelIntersects & ...
2
votes
1answer
49 views

List File Geodatabase Topology

I'm trying to write a script that looks into a dataset and list all the elements in the dataset. The dataset comprises of Feature classes and FGDB Toppology. When I uses ListFeatureClasses, it outputs ...
2
votes
1answer
207 views

What am I doing wrong with QGIS v.clean?

I thought I understood how the GRASS v.clean tool worked in QGIS (in 2.6.1 Brighton) but I keep getting unexpected results and errors with a polygon ShapeFile. I've run the QGIS TopologyChecker with ...
3
votes
0answers
66 views

How to simplify polygon shapefile and maintain topology? [duplicate]

I'm looking for a straightforward answer that actually works...not a 'duplicate question' flag. None of the other solutions posted in similar threads actually work...they all have dead-end answers ...
2
votes
1answer
45 views

ArcMap remove feature-class from feature-dataset

I am using ArcMap 10.0 (Editor). I have got a feature-dataset within a GDB with several feature-classes and an topology. I am unable to find a way to delete/remove a feature class from that ...
0
votes
0answers
40 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
votes
0answers
42 views

How to eliminate sliver polygons with QGIS [duplicate]

I need to remove sliver polygons within a shape, but using QGIS 2.6 generates some failures to the process. I mean the program freezes or shuts down and I don't know why. Maybe there's a bug or it ...
1
vote
0answers
62 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 ...
0
votes
0answers
23 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 ...
0
votes
1answer
53 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 ...
0
votes
0answers
164 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. ...
3
votes
0answers
36 views

Prevent PostGIS Topology from splitting edges on line insert

I'm dealing with a large amount of road data represented with PostGIS Topology types. Anytime I add an edge over another edge, the edge is automatically split and a new node is created at the ...
1
vote
0answers
32 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 ...
3
votes
1answer
97 views

Gaps and overlaps appear after cutting a previously topologically clean shapefile?

I'm using QGIS 2.2 and I have a polygon shapefile which was created by someone else. I have managed to get the shapefile to a topologically clean state by running v.clean but when I tried to cut the ...
6
votes
1answer
127 views

What controls the direction of TopoGeometry Linestrings?

In PostGIS, what if anything controls the direction that topogeometry LINESTRINGs will have when converted to geometry? It doesn't appear to be the order in which the edges are listed in the call to ...
3
votes
1answer
109 views

QGIS Topology Checker select errors

I have used the Topology Checker plugin in QGIS to create rules to identify errors in my layer. For example, I have used it to search for all overlapping polygons. This plugin is great for finding ...
1
vote
1answer
225 views

QGIS - Identify overlapping polygons in single layer

I have a shapefile of buffered points in QGIS. I need to display all buffer polygons in this layer which overlap. I have experimented with the intersect tool, but this only seems to work if I am ...
0
votes
1answer
81 views

Delete all data from a PostGIS topology

I need to delete everything (faces, nodes, edges, anything I'm not thinking of) from a PostGIS topology, but I want to keep my database schema (schemas, tables, columns, sequences, etc.) intact. Is ...
2
votes
1answer
36 views

Is there a a way to add a topology dataset to an mxd with arcpy?

I have a script that identifies certain layers from a folder containing several geodatabases. Part of the scripts purposes, or intended purpose is to have it add a topology dataset to the dataframe. ...
1
vote
1answer
37 views

How to find points present in one layer but not in a second layer, using ArcGIS?

I have two layers, A and B, with B consisting of a proper subset of the points in A. How can I produce a third layer, C, consisting of just those points found in A but not in B. In R, I would just ...
0
votes
1answer
70 views

OSM Data 'gid' column

Eventually I came to know that in order to use pgr_createTopology function to create topology network on my imported OSM data (using pg_routing and postgis on postgresql), apart from the_geom geometry ...
1
vote
1answer
194 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 ...
2
votes
3answers
280 views

X,Y Tolerance vs. Cluster Tolerance

I can set a "X,Y tolerance" or use default when I create a new feature class. I can set a "X,Y tolerance" or use default when I create a new feature dataset. I can set a "Cluster tolerance" or use ...
2
votes
2answers
51 views

vb.net arcobjects determine whether arcmap is in editing session

I have a vb.net arcmap addin which provide a function to validate geodb topology. But there is a problem, when I am not in editing session and use the function, arcmap will crash. In this case I ...
2
votes
0answers
206 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 ...
1
vote
0answers
48 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 ...
0
votes
1answer
40 views

vb.net arcobjects check if topology has error

I follow the esri example for validating topology, is it possible to tell whether topology error exists? The code I use: ' Step 1 - access a topology Dim topoUiD As UID = New UIDClass ...
0
votes
1answer
53 views

arcsde topology register issue

I am in trouble with the topology in a sde database. I create a topology in a dataset from arccatalog, after managing to register it as aversion, I try to validate it from arccatalog, it tells me ...
1
vote
0answers
28 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', ...
1
vote
1answer
42 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 ...
1
vote
1answer
41 views

Working with topology errors sample code error

I am following the sample code from ESRI for checking topology errors using vb.net. But in my workspace an error happened. My code is listed below: ' Step 1 - access a topology Dim topoUiD As ...
0
votes
1answer
354 views

ArcMap topology toolbar validate topology button is disabled?

I find a strange thing when I try to use validate topology button. Most of the buttons on topology toolbar are disabled. Last month when I was using a trial license of ArcGIS, I can use these ...
2
votes
1answer
175 views

How to generate pgrouting source and target with OSM?

Is there anyone here can explain me more details for pgrouting's source and target? I'm wondering how to generate with the given lonlat in OSM PostGIS entities. In pgrouting's website, they are ...
1
vote
0answers
26 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 ...
1
vote
1answer
69 views

Access a topology sample code runtime error when define ITopologyExtension

I encountered a runtime error when I used the sample code from ESRI on Accessing a topology. The sample code is as follows: Dim topoUiD As UID = New UIDClass topoUiD.Value = ...
0
votes
0answers
34 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, ...
0
votes
1answer
38 views

vb.net arcobjects validate topology ITopologyExtension and esriTEEventHint not declared

I am trying to use arcobjects with vb.net to validate a topology (already defined). I am caught even when I use the sample provided by ESRI. The code I use for accessing a topology is: Dim topoUiD ...
1
vote
2answers
114 views

Software to detect intersections (within a tolerance) between 3d polylines

Is there any way to detect intersections (within a tolerance) for a 3d set of polylines? ArcGIS Topology Check seems to project everything into 2d (x-y plane) before checking, so shows a lot of false ...