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  • TopoGeometry commands with postgres are really slowFebruary 12

    After messing around quite a while, I was finally able to get a topogeometry converted from my geometry table following the example of toTopoGeom. I have the topology extension, with a topology schema (SRID = 5367) and a table in the public schema wi

  • topology installed with postgres: functions do not existFebruary 12

    I installed the topology extension to my PostgreSQL 9.4 db with postgis v2.1.8 extension: CREATE EXTENSION postgis_topology But whatever function I try to call, the functions are not recognised. For example: select toTopoGeom(mygeometry.geometry) fro

  • Small World network on a square grid

    Small World network on a square gridFebruary 10

    My aim is to generate a 2D Small World network on a square grid. i.e. 20x20. With a probability of 5%, one node rewires from an adjacent node to a random node of the grid, allowing some long distance edges. Yet, the grid topology should be fixed. Mor

  • Edit polygon borders in QGIS preserving topological correctness (planar partition)

    Edit polygon borders in QGIS preserving topological correctness (planar partition)February 3

    Given a layer of polygons that is topologically perfect, i.e., has no overlaps or gaps between the polygons, is it possible to manually edit the edges of the polygons in QGIS in a way that preserves the topological correctness? As illustrated In the

  • Checking if two WGS84 lines intersect in JavaScriptJanuary 31

    I am trying to work out given two GeoJSON lines (WGS84), if they intersect (i.e. cross one another). Let me give some pseudocode to illustrate: // Providing Line 1 = lon1, lat1 and Line 2 = lon2, lat2 function linesIntersect(lon1, lat1, lon2, lat2) {

  • Moving feature classes between FGDB's creates unknown topology errors January 26

    I am attempting to merge together multiple large feature classes from different FDGB's into a single feature class and am getting unknown topology errors when checking for gap and overlap rules. I have run topology checks on these feature classes bef

  • How to creat a hexagonal topology in ns2?January 20

    I would like to know how to randomly deploy some wireless sensors nodes in ns2. I want to create a area about 100m*100m with randomly deploy some wireless sensors nodes and these node can form many hexagons into a hexagonal topology network. Thanks a

  • Dynamic minimal polygons from intersections of other polygons

    Dynamic minimal polygons from intersections of other polygonsJanuary 16

    Let us have some polygons and polylines that intersect and thus create other polygons from their intersections. I am interested in the minimal ones like in the picture below: Let's consider that the polygon that interests us is Polygon 1, because it

  • Storm supports task or data parallelism?January 15

    I am trying to learn the parallelism and scalability features offered by Storm and read the following article http://storm.apache.org/documentation/Understanding-the-parallelism-of-a-Storm-topology.html. I am confused that whether Storm supports data

  • Using ArcMap Topology to make admin boundaries match up?

    Using ArcMap Topology to make admin boundaries match up?January 8

    I have two separate datasets ('Wards' and 'Census Output Areas'), whose boundaries don't quite match up (see below - wards in red, COAs in grey). Is there a way of automatically adjusting the Ward boundaries so that they align with the Census Output

  • Simplify/generalize Polygons and keep topology of different layers PostGIS/QGISJanuary 7

    i have some polygons of a country, states, districts, communities and i want to simplify the geometry. i already simplified the geometry of each layer but afterwards of course it doesnt fit with the geometry of the higher or lower administrative leve

  • How to remove spikes in Polygons with PostGIS

    How to remove spikes in Polygons with PostGISDecember 15

    I'm trying to validate the topology of a shapefile. I managed to repair cases of overlap and gaps, but i can't resolve cases of spikes. The image shows one example of this situation. I used the comand: SELECT geom, ST_Buffer( ST_Buffer( ST_Buffer(geo

  • Create polygon from lines in PostGIS

    Create polygon from lines in PostGISDecember 9

    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 tried some ways, but I can't get the result. What I'v

  • Tool or program to clean polygon dataset

    Tool or program to clean polygon datasetNovember 18

    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 forest and ID 2 is grass. In general the pol

  • Best search topology for 1 WFE Server,1 App server and 1 SQL Server?November 5

    Best search topology for 1 WFE Server,1 App server and 1 SQL Server? Where to configure the index partitioning,query components and other search components --------------Solutions------------- Its depend how big the servers in term of Memory and CPU.

  • pgrouting - topology creation with explicit node file

    pgrouting - topology creation with explicit node fileNovember 2

    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 geometries (LineStrings) and station geometries (Points) to

  • How to avoid topology errors when digitizing a road network?October 30

    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 topology checker in QGIS, with the option must not h

  • Problem for Map Topology creation in ArcMapOctober 30

    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 happening? my code : IFeatureLayer pFeatureLayer

  • How to increase SharePoint performance?October 29

    Our SharePoint has 2 WFE server and we are facing performance issue. What are the things that have to be considered to increase performance? --------------Solutions------------- Their are couple of reasons which cause the performance issue. High CPU

  • Styles for Vector layers on QGIS

    Styles for Vector layers on QGISOctober 29

    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 seems to work on Qgis. When I downloaded thes

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