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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How to analyze differences between two shape files and put results into a new shape?

I have two polygon shape files of the same region from two different years (1985 and 1997) and I need to analyse the differences between the two shapes resulting in a third polygon shape file ...
14
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5answers
2k views

Find pseudo nodes in free GIS software

Software gvSIG OA Digital Edition 2010 have tools topology for finding pseudo nodes in linear geometry. I set cluster tolerance 0.00002 and maximum number of errors -10000 for 20000 link count linear ...
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68 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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1answer
50 views

How to edit line and polygon layers at the same time?

I have two layers, lines and polygons. Lines are basically the boundaries of the polygons. Is there any way that when I change or reshape the lines the polygons get updated automatically? I normally ...
3
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1answer
114 views

T-shaped polygons

Is there any coefficient that can indicate T-shaped polygons ? Examples of T-shaped polygons :
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0answers
172 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 ...
3
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1answer
91 views

Verifying the number of times a line crosses other lines

I have a series of lines that represent streams. I have a stream line and two flowpath lines in one feature class and two banklines in another feature class. Total of five lines. I then have a feature ...
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0answers
111 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, ...
2
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1answer
211 views

GRASS - v.clean Conflation - How to snap a layer to a base layer

Someone told me in this post that GRASS GIS can handle multilayer topology, what I have not found any information about. I am not a specialist of GRASS GIS so I would need help with that if its really ...
4
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1answer
369 views

Topology problems with QGIS/GRASS

*edited file links below I'm working on several NGO projects at the moment, all of which are reliant on being able to use a district level map with some 490+ features, and I am running into some ...
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0answers
96 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 ...
3
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5answers
1k views

How to Identify and Delete duplicate vertices?

I am trying to figure out how to delete duplicate vertices. I have successfully determined that there are duplicate vertices using PLTS Data Reviewer, but I am confounded as to how I identify and ...
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0answers
48 views

How can I build a network from a latitude, longitude points? [closed]

How can I build a network from a latitude, longitude points? I have some points(latitude and longitude) and i wish to build my network based on this points.
2
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3answers
199 views

How to correct topology on a shared boundary by removing nodes from a feature?

Maybe you can help me solve a problem regarding topology cleanup that I recently came a cross. I have two layers with bunch of polygons (or feature classes as I'm in the ESRI world) that should share ...
0
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0answers
43 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 ...
5
votes
3answers
2k views

How tool to split polylines into two-part lines at vertices in ArcGIS for Desktop 10.1?

I'm using ArcGIS 10.1 SP1 at and we have a problem. There is a serious topology bug that I've mentioned in another question that is affecting our workflow. At present, Esri has stated the fix will be ...
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0answers
243 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 ...
4
votes
4answers
341 views

Is there a way to snap to apparent intersections in ArcGIS 10.1+?

Suppose there are two lines in an ArcMap 10.1 or 10.2 editing session that cross but do not intersect, per se. This is the case when new lines a drawn. Is there a way to snap to the point where the ...
5
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2answers
1k views

What's the difference between hypsography and topography?

I've recently come across some data that has been labeled "hypsography". I looked it up and it sounds like topography. But this data source has data labeled "topography" separate from its ...
2
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1answer
132 views

measuring adjacency between polygons

I am working with some land ownership data. I would like to identify parcels the have small adjacency between other parcels. In a nutshell I want to identify where there is a small overlap between ...
1
vote
1answer
172 views

Problem when creating database based on template_postgis

I have created a PostGIS template but when I try to create a database based on this template this is what happens: Connecting to the template: \c template_postgis; You are now connected to database ...
2
votes
0answers
87 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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2answers
577 views

Doubts about how pgRouting topology is built and how flexible it is

I'm learning pgRouting, to validate if it can be used in a project. I have several doubts. Mostly related with how could I "fill the gap" between the "bricks" it provides and the real world ...
1
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1answer
443 views

Insert Vertex into Polyline based on Point layer using arcpy

This is essentially the same question asked here that was not answered... Using ArcGIS 10.1 Advanced I have a point layer with points that represent the intersection of a driveway with a street ...
4
votes
2answers
471 views

Is there website with list of common QA/QC errors?

As I am working on reviewing my soils spatial data, and I am doing my QA/QC I placed a point layer to check for errors. I add the field column to mark the error and state the error. I recently ...
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1answer
119 views

ESRI ArcMap Topology rules on multi story buildings

I would like to run some topology rules to find snapping errors in our polygons but I am running in to the problem where we are working on multi story buildings with every polygon regardless of floor ...
9
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2answers
568 views

Are there Desktop GIS alternatives to ArcGIS 10.X for topology and vector conflation?

Is there any options other than ArcGIS for Desktop for topological rules and automatic topology integrity enforcing in a Desktop GIS? I am looking for something that will automatically snap features ...
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0answers
51 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 ...
6
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3answers
2k views

How to fill a hole in a multi-polygon layer on QGIS 2?

I need to fill a hole in a multi-polygon layer on QGIS 2.0. I've set the snapping option for the layer as follows : mode: to vertex and segment tolerance 4 pixels avoid intersection "enabled" ...
1
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1answer
169 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, ...
2
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0answers
103 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 ...
12
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1answer
1k views

What is topojson and how is it different than geojson?

This is a conceptual question. What are the differences between these? and what are the pros and cons of these formats?
2
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231 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 ...
3
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3answers
220 views

How to identify misaligned corners in PLSS sections

Sometimes PLSS section corners do not align How could I automate the detection of these corners and generate a new shapefile showing where this occurs? I have a shapefile of 147k section polygons ...
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0answers
290 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
36 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 ...
4
votes
5answers
2k views

How to select all dangling polyline features with Arcview license?

I have a city roads shp file and would like to identify (select) all the locations where a roads ends (in other words dangles). I am working in ArcView 10. I do not want to use a topological tool ...
2
votes
1answer
260 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, ...
2
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0answers
437 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, ...
3
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1answer
169 views

How can i topologically sort 2D triangles and put in an array?

I have a set of 2D triangles in a Geometry array which together forms a connected strip when placed them according to edge adjacency. However, in the array they are not in topological order based on ...
2
votes
1answer
188 views

Tools/Script to reshape automaticaly topologic edges within a given distance in ArcGis 10?

I have a footprint feature class and a land use cluster feature class. I am looking for a method/tool/script that would allow me: to reshape two edges into one (topologically) to decide at which ...
11
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4answers
2k 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 ...
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0answers
94 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 ...
3
votes
1answer
266 views

SDE Topology dirty areas don't go away

Just looking for an explanation on SDE Topology dirty areas that don't go away. My workflow involves editing a version of SDE data, then once finished I use the Validate Topology in Current Extent ...
13
votes
2answers
1k views

How to generalize SpatialPolygons and conserving topology in R?

I would like to generalize a SpatialPolygonsDataFrame in R to make plotting more efficient. The polygons I have result in huge pdf plots that are slow to load and hard to integrate into a document. ...
2
votes
1answer
730 views

Grass v.clean.snap with Polygons

I am doing some topology testing using Grass in QGIS. I am hoping to snap nodes to eliminate gaps between polygons. When I use the v.clean.snap function in Grass it does not work on polygons. When I ...
4
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0answers
265 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 ...
4
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0answers
141 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, ...
7
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3answers
750 views

Snapping start- and end nodes of lines to other lines in PostGIS

There are plenty examples that show how to snap lines to points, but I haven't been able to find any (fast!) way of snapping the start- and end nodes of line strings to nodes of other lines. ...
4
votes
1answer
593 views

How to repair and clean contours from high data resolution (lidar)?

I'm unsuccessfully trying to make a bathymetric map with contours extracted from Lidar data at 1 m resolution. The extracted contours have a lot of artifacts like dangles and islands. First I used ...