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Questions tagged [topology]

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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60 views

Checking if vertices of polygon are in clockwise or anti-clockwise direction in QGIS?

Is there a simple way to calculate a field in QGIS indicating if the vertices of each polygon feature in a layer are in clockwise or anti-clockwise direction? For simplicity, lets assume the layer ...
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1answer
29 views

Adding ArcGIS topology rule that allows Attribute based exceptions?

I want to run a topology - one is geometry based where I am looking for overlaps as error, but in my database I want to keep some error as exceptions (such as road over waterbodies). One option is ...
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37 views

Seeking Web GIS to edit polygons topologically on browser? [closed]

I would like to know what open source Web-GIS environment (GIS server, additional applications,...) would give me the functionality to edit polygons topologically on the browser (client side)?
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1answer
31 views

Discerning dwelling types in QGIS? [closed]

In QGIS, I want to discern between a number of building types, based on topology. I have data on buildings, parcels and addresses. I'm having a hard time to discern between row/terrace, end-of-...
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18 views

Detecting bow in lines of file?

We have a file made in CartaLinx that has thousands of polygons manually vectorized. Apparently, some of the lines go over themselves so the file corrupts frequently. Cartalinx can't find the bows ...
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0answers
60 views

How do I select the longest connected lines from PostGIS ST_ApproximateMedialAxis?

I used PostGIS ST_ApproximateMedialAxis to transform polygons representing mountain ranges into a series of lines. Now, I'd like to select only the "longest" line segment for each group, so that I ...
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64 views

How to automate topology check/fix in QGIS?

Short version: I have a layer with 19483 features with plenty of topological errors and I would like to fix/review them as many as possible in an automated way but don't know how to do it. ...
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21 views

error 999999 add rule to topology management

I was trying to create a topology with some rule, but I have problems with the rule "Must Be Covered By Feature Class Of". I get the error "999999: Error executing function." This is the code: WU =...
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18 views

Cannot Create Topology in SDE

I am trying create a topology for a zoning dataset in my SDE feature dataset. I've run into a few issues. First off was an issue with versioning that this questions resolved: How to solve "Cannot ...
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2answers
30 views

When topological editing how can I automatically snap lines to lines close to them?

Using ArcMap 10.3, advanced license, I have a data set of road lines and another data set of road surface conditions, and I need to apply the road conditions to the road line as an attribute where it ...
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0answers
30 views

QGIS topology check shows different topology check results for same area

I used QGIS topology checker for parcel data of an area in QGIS 2.18. The rule used was- 'Parcel must not have gaps'. The result showed many error (gaps) and while zooming in and zooming out, the ...
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18 views

Arcpy export topology errors bug

I have created an ArcGIS Python script tool that creates and validates a topology dataset, exports the topology errors and performs some analysis between the topology errors and their source feature ...
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1answer
54 views

Fixing bad topology on polylines with QGIS

I've been sent a shapefile containing 12 layers of some city's road system. Each layer depicts a portion of the road system, and all of them partially overlap on the map. I'd like to work on the sum ...
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3answers
78 views

Align one polygon boundary to another boundary

As visualized in the picture as an example, two polygons should be aligned to each other. The boundaries of the green polygon should not be changed. The blue polygon may therefore only be adapted to ...
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0answers
23 views

Handling dangling nodes in ArcGIS Desktop?

I have a datafile of line features. The creation of a topology revealed that there are too many dangling nodes to be corrected manually. I was thinking of snapping to the closest line feature in an ...
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0answers
68 views

ST_Difference in PostGIS : problem with geometry result (Polygon)

I'm experimenting a result issue using the ST_Difference spatial function in PostGIS. Input : Feature 1 and 2 overlaps each other. Both contains 5 vertices, like a rectangle (4 plus an additional ...
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1answer
82 views

Repairing all topology errors at once in ArcMap?

In 2012 an ArcMap user wrote Automatically fixing multiple errors using Fix topology error tool?: I am a ArcGIS.10. user. I'm want to solve multiple errors using the fix topology error. So I ...
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0answers
55 views

TopologyException issue when doing intersection in Geopandas?

When I do overlay processes like intersection, I mostly get: :TopologyException: found non-noded intersection between LINESTRING (229971 4.39944e+06, 229971 4.39944e+06) and LINESTRING (229971 ...
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2answers
195 views

Is the erratum about polygon point order in GeoJSON correct?

The GeoJSON specification (RFC 7946) states that for polygons: A linear ring MUST follow the right-hand rule with respect to the area it bounds, i.e., exterior rings are counterclockwise, and holes ...
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0answers
25 views

Topology validation problem

I have a problem with a feature class which has a topology problem between two polygones. The problem is when I select an error area and I merge It, the error remains. The two rules that I used are : ...
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0answers
173 views

QGIS 3.0.3 topology checker to find gaps between polygons

When using QGIS 2.x I have used Topology checker to find gaps between polygons, crossing lines and duplicated points/vertex. I also liked that it shoved a list of errors where I could zoom into each ...
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0answers
56 views

I can't import or export a topology

I tried to export a topology using the function arcpy.ImportTopology_defense(GDB_input,os.path.join(arcpy.env.scratchGDB,dataset+".xml")) but it throws an error : AttributeError: 'module' object ...
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21 views

topological edits in ArcGIS for Server

I am developping a ServerObjectExtension using ArcObjects to extend an existing map-service. Now I want to perform some edits. There are many featureclasses that have to be handled together. However ...
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87 views

Self-Contact Topology Errors?

I've been trying to clean up some vector data sets so that I can reproject them to WGS84 but I keep finding topological errors that fail the process. The one error I can't resolve involves a node on a ...
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1answer
67 views

Editing two layers topologically in QGIS?

I have different polygons in layer a_input. The Polygons are adjacent and connected inside the layers and it should be. The Polygons in layer a_input have to fit adjacent to a polygon of layer 2 ...
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0answers
34 views

Topology checks and error marker

I have a problem in QGIS. I want to find overlapping polygons but not only which polygon overlap with another but the exact node(vertex) that intersect or overlap. The error marker doesn't show you ...
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0answers
25 views

Versioning error when creating a Topology on a File GDB

Im having an issue with the 99999 Error. Im creating a Topology dataset for each of the featureclasses within a GDB. For some reason my script works for some feature classes and errors on others. I ...
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1answer
72 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 ...
2
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1answer
76 views

Fixes to achieve topology in QGis not working

I imported a .shp file to QGIS with polygons from a non-topological database. Polygons were adjacent and shared borders, but most nodes didn't coincide. I then proceeded to fix all nodes and ...
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2answers
70 views

Is there a way to save and share topology rules in QGIS?

I would like to create a set of topology rules and use them over and over again. I would also like to be able to share them with my team. Is there a way to do this in QGIS? I'm using QGIS 3.0 but I ...
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0answers
61 views

Creating custom topology check script for QGIS?

In a comment on an answer to Accessing python module for QGIS 3.0 topology checker from Python script? I asked if I could import the topology checker plugin in QGIS in a python script similar to the ...
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0answers
56 views

Invalid Topology: Cannot Open Cache File when trying to do a dissolve

I'm trying to perform a dissolve to take some data that is at the Census Block level to the County level. I'm dissolving by the County ID and doing a Statistic Field for various attributes (1 SUM, 2 ...
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1answer
109 views

Accessing python module for QGIS 3.0 topology checker from Python script?

There is a similar question Access QGIS Topology Checker from Python, however this user was wanting to run the topology tool while I want to import certain rules. For example in arcgis arcpy....
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1answer
32 views

Handling Topology in ArcGIS Online?

Can ArcGIS Online act as a solution for handling topology? For example, if I have a hosted feature service with topology in it, can I maintain the topology in the hosted feature service using tools ...
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1answer
29 views

Loading points and polylines into PostGIS database and creating connectivity between them using topology?

I am new in PostGIS, and I am trying to create connectivity(using topology) between 3 sets of points and polyline to model an electrical distribution network. Does anyone know how to do this?
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1answer
21 views

QGIS and topological complexities/erros in polygons

I am using QGIS 2.14.19-Essen on Windows 10. I have a polygon shapefile of ecorregions in the Southern Cone of South America (Fig. 1), which is composed of 317 different features. I need to make it ...
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3answers
97 views

Removing overshots (dangles) using FME or FME/MRF Transformers

I have a network of many connected lines where there is overshoot topological errors. Is there any way to remove them using FME Desktop?
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1answer
182 views

QGIS Check Geometries [closed]

I'm trying to get a network in shape (pain, such unending pain) and have turned to Check Geometry to find errors but I repeatedly get told that "The test layer set contains a layer selected for a ...
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1answer
36 views

Adjusting / snapping a polygon to another in ArcGIS Desktop

I have a feature class and/or Shapefile that consists of 2 complex polygons. I would like to remove the small gaps between these polygons 1 & 2, but I want polygon 1 to remain exactly the same ...
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2answers
82 views

Filling spaces between polygons using ArcGIS Pro?

I have a polygon with 4 attributes (1,2,3 or 4). In the process of creating this polygon (merge/erase/union), there were gaps left between 1 and 2, with some of the gaps having slivers of 3 or 4. ...
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1answer
41 views

Touching Polygon Intersection

I have two touching Polygons (two neighbouring counties) and there intersection is a MultiLineString, where: len(list(counties["King's Co."].intersection(counties["Queen's Co."]).geoms)) list(...
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1answer
151 views

Topology checker does not show error for one polygon fully within another polygon as overlap

Its about QGIS. In the attached screenshot, the topology checker does show error for the overlap for the two large polygons (1 and 2); but it does not show an error for the smallest (3) and the left ...
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0answers
159 views

ESRI Polygon cutouts (neg. space) become multiple layers in PostGIS

I have a single MULTIPOLYGON from ESRI ArcGIS with 10,000+ sub-polygons in a Shapefile, some having > 1.4 million vertices. I'm importing the data into PostGIS (ogr2ogr or shp2pgsql, same results) so ...
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1answer
34 views

how to ensure topology using v.overlay?

Trying to find the maximum of a several Shapefiles I execute a cascade of unions. Out of all the tools, so far GRASS v.overlay seems to be the one working the best. However I am running into trouble ...
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1answer
75 views

Finding intersection topology errors in QGIS

I would like to find the intersection topology errors in a line layer using QGIS 2.18. In the topology checker I found no intersection errors. I know GRASS v.clean and v.build commands can solve these ...
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1answer
59 views

Connecting Add Feature Class to Topology to Add Rule to Topology in ModelBuilder?

I have a question regarding to how to connect the outputs of "Add Feature Class to Topology" to "Add Rule to Topology" in ModelBuilder. As the picture shows, I want add a rule called Must Cover Each ...
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0answers
67 views

solve Topology error in Grass using QGIS?

I want to build a raster from a vector layer by using "v.to.raster.attributes" in QGIS but its not working and give me an error to build a topology using v.build. I build it but after that i have no ...
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0answers
24 views

Build the edge-vertex topology from a polyline feature class in ArcGIS [closed]

I have a polyline feature class called line_1. What I want to achieve is the edge_vertex topology. Specifically, I want to generate a new polyine feature class called line_1_new, by adding two new ...
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0answers
157 views

Automating topology error fixing with ArcPy?

I have a web application where folks upload a zipped up file geodatabase, I unzip it and manipulate the feature classes and then transfer them using insert cursors to an SDE database. I am wondering ...
2
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1answer
149 views

pgrouting no result // topology problem

First of all, I am new to map making, and I am mostly relying on tutorials to learn. As part of a project, I am making an airway map using QGIS and I do it by uploading the points with lat/long thru a ...