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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Determining if landlocked polygons in ArcGIS Desktop?

Imagine that I have the need to determine landlocked countries. Is there a way to do it automatically? Any known implementations? The target platform on this will be ArcGIS.
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715 views

How do I describe a special relationship between connected edges?

Consider this simple situation where three edges connect at a node: I’d like to write a succinct and clear description of the relationship between A and B in such a way that differentiates it from ...
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1answer
305 views

Is there a standard st_relation_readable() function for translate DE-9IM strings?

Spatial databases, such as PostGIS, implement the DE-9IM model with function st_relate(), which returns a string with domain of {0,1,2,F}, meaning 0=point, 1=line, 2=area, and F="empty set"... See ...
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1answer
419 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 ...
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90 views

Create polygon from lines in PostGIS

I'm trying to divide a polygon in smaller polygons from a line, but I think I can't use the st_split function. What I need is to create small polygons inside a big one, using linestring grid. I've ...
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417 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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2answers
209 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 ...
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48 views

How to check if a point is snapped to a line in QGIS

I have two vector classes, sg_point and sg_line. Any sg_point HAS to be snapped to a sg_line. I should not find errors if I use snapping correctly, but in case there are errors how do I check in QGIS? ...
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2answers
125 views

Tool or program to clean polygon dataset

I have a polygon dataset (shapefile, mapinfo tab file) which I would like to "clean" to be topologically correct. The polygons are assigned an ID which represents a specific class. For example ID 3 is ...
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1answer
32 views

pgrouting - topology creation with explicit node file

Learning pgrouting, I would like to build a simple public transport routing engine. Starting with a simple metro network (DC in my case, see excerpt below), I would like to combine the line ...
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47 views

Problem for Map Topology creation in ArcMap

I will create a map topology in ArcMap. My code defines the layer in my map topology but after call EditTopology Tools, a message show "No topology .... bla bla bla.." Any ideas why this would be ...
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84 views

How to avoid topology errors when digitizing a road network?

I am working on a road layer project. For the snapping option I'm using the mode to vertex and segment and tolerance 5 pixels. When zooming in (to the max) I do not notice a gap. But when I use the ...
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1answer
66 views

Styles for Vector layers on QGIS

I'm trying to do some habitat suitability modelling on QGIS. I've downloaded several vector maps from Ordinance Survey (OS). So far I've found a Cartographic stylesheet for "OS VectorMap Local". This ...
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1answer
102 views

Automatic creation of polygons from Feature Class points in ArcGIS for Desktop?

I have two point feature classes, let's call them A and B. They are well-spaced and the points are non-overlapping: My objective is to create a topology using these two sets of points by connecting ...
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1answer
292 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 ...
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5answers
2k 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 ...
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1answer
85 views

Arc-node topology data structures in Python GIS packages

I am looking at using the traditional arc-node topological data structure to make some spatial data analysis more efficient. I would like to avoid reinventing the wheel. Is there an implementation in ...
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2answers
303 views

Convert SmallWorld GIS topology to pgRouting topology

Is there any way to convert SmallWorld GIS topology to the format that pgRouting use? My costumer have use SmallWorld GIS and make his topology on it. but when he export his information as shape file, ...
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1answer
159 views

QGIS Topology Checker Wrong

I use topology checker and add a rule that polylines must not have dangles. It find errors for all 36 polylines but I think some topologies are correct at the right side. Can you help me how can I fix ...
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2answers
335 views

What is nontopological geometry?

I need a simple understanding of nontopological geometry. I am completely new in this area so please correct me if I am wrong. As far as I understand in topological geometry the object(say a line) ...
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0answers
53 views

ArcGIS: Is there any way to use topology on data in different feature datasets?

I am using ArcGIS 10.2 desktop on an SDE/versioned environment. We use the ESRI local government information model, except that we do not use parcel fabric. I am responsible for maintaining several ...
2
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1answer
403 views

How to test for 'if arcpy.exists' with RemoveFeatureClassFromTopology stand-alone script?

I have some datset topologies that i want to loop through, but I need to test for the assignment of feature classes so the scripts dont fail. (Using Win 7, ArcGIS 10.2, Python 2.7.5 and a file GDB) ...
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3answers
855 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 & ...
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2answers
318 views

How can I remove the gap between two polygon boundaries in QGIS?

I have a couple of messy polygon boundaries (example data) that should share a boundary but don't: I've had a look at some suggested tools for a similar issue using ArcGIS in a separate question ...
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1answer
109 views

start editing encountered one or more layers with error and can not continue this data is not editable

I create two feature classes by importing an already existing layers then I create a topology and I set the rule such that a point feature class must be covered by endpoints of the other line feature ...
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1answer
22 views

Territories that are not connected

I am looking for territories that are divided between two or more countries in a non-contiguous way. E.g, country A receives the western part of the territory, then country B receives a part to its ...
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0answers
106 views

Problems using GRASS tools for topology validation in QGIS

I'm working with a shapefile of Enumeration Districts (Setores Censitários) of the 2010 Brazilian Census. Enumeration Districts (ED) are smallest areas for which Brazilian Census data is available. ...
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204 views

How to add rule and add feature class to topology using arcpy and stop getting error 000732?

This script successfully added feature classes to topology when that is all I had scripted it to do. Now I've added the add rule parts (#added) and it's still just adding feature classes without ...
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1answer
80 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
54 views

Select and count street pattern features (morphology) using ArcGIS for Desktop?

I'd like to be able to select and count the number of cul-de-sacs, lollipops, dead ends, or other types of street structure in a hillside community.
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1answer
227 views

What's difference between Topology and Check Validity in QGIS?

I would like to know what the difference is between the Topology Checker and Check Validity tools? Is there anyone who knows of a good document or tutorial that explains functions of these tools? ...
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2answers
146 views

Topological errors after dissolve - how to avoid/get rid of?

After dissolving a layer in QGIS 2.8, I get a lot of topological errors in the new (dissolved) layer. Any suggestions as to how to get rid of these errors without manually editing each one? ...
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64 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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1answer
166 views

How to correct topology area boundary errors (slivers/gaps) on arcs in arcgis / arcsde

I use arcgis 10.1 (arcinfo licence) with arcsde to connect to a SQL Server database. The initial dataset has around 100k polygons (used for land registration, having a resolution that is around 1cm ...
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242 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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1answer
78 views

Implementing topology rule Line Feature Class should not overlap with Polygon Feature Class in ArcGIS Desktop?

Is there a way to setup such a rule in ArcMap 10 Topology that Line Feature Class features shouldn't overlap with Polygon Feature Class features?
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1answer
155 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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2answers
142 views

QGIS Editing: move - both - nodes after Cut has been performed

I just ran into unexpected behavior while editing a polygon shapefile in QGIS 2.8.2. Scenario: A polygon: Then I cut that polygon into two seperate poygons: Then I use the Node Tool to move a ...
2
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1answer
143 views

Identifying “Must not connect point more than one line feature” errors in electrical network?

I have attached an example image to show the problem: This is electrical network data single service point to connect more than one Service pole. Is it available any topology rules? I would like ...
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1answer
82 views

PostGIS Topology Requires Admin

I am running PostGIS on an Ubuntu server. I am able to add the Topology extension via CREATE EXTENSION, but when I try to use it as anything other than an admin I am denied permission. I ran GRANT ...
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1answer
34 views

Double Entries/ Errors with Digitizing Polygons

I have a layer that has errors, i mean polygons have double entries (digitized twice), i can edit manually but there's a lot of attributes and it will take ages to clean the data. Is there any short ...
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1answer
203 views

Parsing path and calculate value in model builder

I am experiencing an issue with the model only tool calculate value. I am attempting to use the parse path and calculate value model only tools to force a feature dataset into the create topology ...
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2answers
1k views

Arc node topology in ArcMap

I would like to implement an arc node topology in arcmap. Do you know how can i build node topology from line layer in ArcMap 9.3.1?
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0answers
300 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 ...
0
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1answer
113 views

Delete Features from a feature class that participates in a topology

I have an enterprise geodatabase and I would like to delete features using the tool from a feature class that resides in one of the feature datasets and participates in a topology. I tried using the ...
4
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2answers
1k views

How can I identify gaps in polylines and polylines with more than one end point using ArcGIS 10?

I have a multipart polyline shapefile containing a large number of lines, some of which are broken by gaps and some of which have more than one start and end (by mistake - see attached). I need to ...
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1answer
1k views

File Geodatabase XY Resolution and XY Tolerance

Here - http://gisintelligence.wordpress.com/2011/04/19/limiting-xyz-geometry-drift/ I found the description of XY Resolution and XY Tolerance in "Arcgis World". I have a question - my cadastral data ...
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2answers
1k views

Dissolve polygons - group to others with touching corners

I am working with some data that shows land management. There are many places where corners "touch". I would like to dissolve my dataset so that features are grouped (dissolved) with those that they ...
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1answer
66 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 ...
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2answers
858 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. ...