1
vote
0answers
18 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', ...
2
votes
1answer
68 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
1answer
52 views

PostGIS: Update child geometries based on parent

I'm using Leaflet and postgis in a case where using Leaflet draw plugin I draw a polygon first like this Now, I draw a line which cuts the polygon and using line and polygon geometry, based on ...
6
votes
1answer
67 views

Suitable algorithms for simplifying isochrone polygons

I'm looking for an algorithm for simplifying isochrones which were generated using OSM data. These are generally characterised as having lots of small "holes" mostly due to missing OSM data but also ...
2
votes
1answer
49 views

Spike finder in PostGIS

I tried to modify spikeRemover from Schmidt & Krüger. My goal it's to obtain, for each polygon, the position of the spikes. I don't need to remove it. For some reason, that I can't figure out, my ...
4
votes
1answer
118 views

PostGIS table to network analysis

I use PostGIS 2.0 and Python API (GeoAlchemy) to work with it. I want to convert topological informations (points, lines, faces) from PostGIS tables to topological network (points, lines) to study it ...
1
vote
0answers
60 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, ...
0
votes
0answers
89 views

What does pgr_createTopology() expect for a table parameter?

In this sample http://docs.pgrouting.org/2.0/en/doc/src/developer/sampledata.html#sampledata there is this function: SELECT pgr_createTopology('edge_table',0.001); I understand that this creates a ...
1
vote
1answer
129 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 ...
9
votes
2answers
462 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 ...
4
votes
3answers
431 views

Create a network topology for pgrouting with grade separation

I have built a network using Ordnance Survey's ITN data and I can solve routes across the network. What I need is to build in grade separation topology for overpasses and underpasses on the network so ...
4
votes
0answers
202 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
votes
0answers
115 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
4answers
324 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 ...
8
votes
1answer
290 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? ...
5
votes
1answer
741 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 ...
14
votes
5answers
1k 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 ...
8
votes
2answers
537 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 ...
17
votes
1answer
1k views

What's the status of Postgis 2.0 topology support in QGIS?

Having followed the Postgis developments over the past 6 months I have noticed a bunch of features which seem to be incredibly cool especially in the area of topologies and associating calculations on ...
7
votes
1answer
2k views

Ring Self-Intersections in PostGIS

This is a follow on from previous question. You will see I am a new PostGIS user. I have looked at the validity of the topology in my data and find around 1700 topology issues in the landcover ...
13
votes
1answer
993 views

Identifying topological relationships using PostGIS

I'm trying to perform a basic typology analysis using PostGIS. My objective is to find any polygons that touch other polygons. To do this, I thought the ST_GetFaceEdges would work (reference). I want ...
6
votes
2answers
725 views

What does 'building topology' mean for pgRouting?

From a couple of answers at gis.stackexchange.com and at the pgRouting mailing list I have found out that pgRouting 'builds topology'. What does that mean? If for example we import an .osm file into ...
8
votes
2answers
897 views

How to preserve topology while editing polygons in OpenLayers?

I’m facing this issue: I have a chloropleth map based on a set of polygons with some data. Using WFS-T (postgis, geoserver, openlayers) I am able to edit the geometry of the polygons. This works fine. ...