Topology describes non-metric relationships among geometric figures, such as adjacency, containment, and orientation.
2
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0answers
32 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 ...
0
votes
0answers
16 views
Possibly corrupt polyline file is causing making polygons problematic.
I used the Feature Class to Polygon tool in ArcMap 10.0 to create a polygon from a polyline shapefile and some polygon boundaries (polylines) are disappearing in the process. The polyline shapefile ...
1
vote
0answers
29 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, ...
3
votes
3answers
54 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
117 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 ...
2
votes
3answers
106 views
How to clean layers from non topological databases?
I'm doing my internship in a consulting office which is switching from MapInfo to QGIS/GRASS 1.8.0.
I posted here a few days ago about the way to clean a polyline from a Lidar data with v.clean.
...
8
votes
8answers
1k views
How to build topology without an ArcEditor or ArcInfo license?
I have a huge dataset that I am capturing that was full of errors previously and I want to make sure that the new version is error free - which can be very time consuming with only an ArcView standard ...
3
votes
1answer
76 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 ...
0
votes
0answers
27 views
generate hydro network topology on a stream network
I want to generate hydro network topology on a stream network without calculating catchments and drainage points.
My initial data are a Line layer (river network) and a DEM10 and the target is to ...
1
vote
0answers
232 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 ...
4
votes
3answers
93 views
Is there a simple tool to split polylines into two-part lines at the vertices in ArcGIS 10.1
Background: I'm using ESRI ArcGIS 10.1 SP1 at my office, Baltimore County Government, and we have a problem. There is a serious topology bug that I've mentioned in another question that is affecting ...
4
votes
1answer
91 views
Learning resources for beginning differential topology for a programmer?
With this question I'm looking for suggestions about how and where to start learning differential topology starting from a good base of linear algebra and geometry, also consider that this know-how is ...
1
vote
0answers
42 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
3
votes
2answers
44 views
How to store and edit data with a defined topology using open software and formats?
I'm looking for a way to store and edit spatial data that preserves topological information.
In my concrete application, I need to represent triangular meshes, which consist of unique nodes and ...
2
votes
1answer
77 views
need help for script checking topology using ogr in python
My main goal is to create a new feature indicating if the line features intersect each other as well as if they are not connected to a feature.
My problem is how to identify the intersecting and not ...
6
votes
2answers
350 views
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 ...
2
votes
0answers
116 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 ...
1
vote
1answer
99 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 ...
0
votes
3answers
70 views
How can I easily detect gaps in a polyline using arcmap 10.0 (arcview license)?
I'm making routes by selecting links from a streets layer which I export as a new temporarely layer in arcmap 10. This layer which I call route_temp unfortunately can be very long and contain gaps, ...
3
votes
1answer
116 views
Simplification algorithms for 3D topology
My problem is about simplifying a given topology that can be opened ( an usual 3D reconstruction of a given square on a map ), totally closed (like a perfect sphere) or a topology with holes ( a ...
7
votes
2answers
923 views
How to check Topology in QGIS?
I have two Shapefiles with Polygons ( City and Forerst)
Is there a Plugin who is able check the topology (QGIS)? Like "Knots do not overlap" or something like that? I dont want that they overlap.
...
12
votes
2answers
723 views
How to generalize a polygon file and maintain topology in QGIS?
my problem: I have a polygon-file in shape-format, which I need to generalize. How can "split" the polygons into lines, generalize and than "rebuild" the polygons, so that I can ensure, that there are ...
0
votes
0answers
49 views
Fix Topology Error Tool & Error Inspector not valid in ArcInfo 9.3 [closed]
I cannot use the above tools in my ArcInfo 9.3. Can you please tell me the possible reasons to this problem and possibly the solutions.
3
votes
1answer
127 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 ...
2
votes
4answers
135 views
How can I create polygons of the area surrounded by roads / lines?
I'm currently trying to create polygons that represent the areas surrounded by roads. The roads are stored in PostGIS as points / lines so I have flexibility over what I can do with them.
I'm ...
1
vote
2answers
92 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 ...
8
votes
1answer
156 views
How to add topology to PostGIS 2.0?
I have installed PostGIS 2.0 and need new topology but it doesn't seem installed by default. I found a lot of command line to install postgis 2.0 with topology but is there a way just to add topology?
...
1
vote
0answers
81 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 ...
4
votes
2answers
224 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 ...
5
votes
2answers
152 views
How to solve “Cannot create topology” in ArcCatalog?
I have a FileGeodatabase in ArcGIS 10.0 with a feature dataset and five feature classes (3 polygon shapes, 1 line shape, 1 point shape).
I'm trying to create a topology to verify some vectors. ...
3
votes
2answers
323 views
Topology error in ArcGIS for SDE 10. “Cannot create topology”
When trying to create a topology for a polygon feature class in ArcSDE. I right click the feature dataset that the feature class resides and try to create a new topology. I get an error saying, "The ...
3
votes
0answers
141 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 ...
5
votes
1answer
655 views
How to create adjacency matrix of topology graph of arc map for shortest path?
I have created a topology graph of a polygon feature and I want to find the individual FIDS of the lines of the polygon. I want to construct an adjacency matrix to create the shortest path. How can I ...
10
votes
2answers
392 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 ...
3
votes
2answers
178 views
How to find self-intersecting polylines using ArcObjects?
If I have a polyline, how do I figure out whether it is self-intersecting? I tried to use ITopologicalOperator.IsSimple Property, but it always returns true.
Are there any ways of doing these kind ...
3
votes
0answers
45 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.
2
votes
1answer
51 views
How can i identify this error? Must not connect point more than one line feature
I have attached an example image to show the problem: This is electrical network data sigle service point to connect more than one Service pole. Is it available any topology rules?
I would like some ...
3
votes
1answer
113 views
Splitting polygons leaves null values
I'm trying to split polygons with overlaping line features, using Split Polygons tool from Topology toolbar. The problem I encounter is that only one from new polygons have old attributes and others ...
1
vote
1answer
33 views
Line FeatureClass shouldn't overlap with Polygone FeatureClass
Is there a way to setup such a rule in ArcMap 10 Topology that Line FeatureClass Features shouldn't overlap with Polygone FeatureClass Features?
2
votes
0answers
121 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 ...
8
votes
2answers
379 views
How to speed up space partitioning in postgis?
I've a bunch of overlapping polygons and I'm trying to partition the space to avoid having overlapping ones. I think my problem is fairly simple.
Using some ESRI product and ...
2
votes
1answer
79 views
Compiling a list of units that border each other
I have a shapefile of U.S. counties. I am interested in compiling a list of those that border each other.
In particular, I am interested in those that border each other but are in different states. ...
7
votes
1answer
399 views
Advanced Polygon and Parcel Splitting
While I am still struggling to divide polygons into same sizes in ArcGIS (we are using ArcView 3.0 scripts now which work fine), I now have an even much more complicated problem:
I would like to ...
4
votes
1answer
285 views
How you can repair invalid topology errors within postgis?
I've imported the shapefile of corine land cover project to my postgis database and the
select gid, ST_IsValidReason(geom) from gis.clc2000 where not ST_IsValid(geom);
returns in every occasion
...
2
votes
2answers
801 views
How to repair topology of a shapefile?
I performed an object-based image analysis using ENVI EX, and each of the classified features were exported as a shapefile. I transferred those shapefiles into ArcMap 10, and tried to intersect them ...
2
votes
1answer
39 views
how to judge the side from a point to a linestring
I'm working with NTS (NetTopologySuite), I get point geometry and a directed linestring, how to judge the side of the point locate with the linestring? one the left side, right side, or just on the ...
3
votes
2answers
269 views
Getting line FID from polygon ITopologyGraph
I want to export polygon Arc list to txt file for that
I created topologygraph for personal geodatabase feature class (polygon)
using ITopologyGraph::build.
I got polygon FIDs but I am not getting ...
4
votes
2answers
383 views
Snapping two polygons together
I have a problem with two vector layers, both polygons. I have been digitising an historical map which contains large areas called townlands, filled by smaller areas called fields. I digitised both as ...
1
vote
0answers
67 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 ...
6
votes
1answer
195 views
Algorithm to fill the gaps adjacent to parcels
I would like to find a way to fill the gaps between the road and its surrounding parcels, like described in picture below:
I have different parcels like A and B , i want to fill the gaps by adding ...
