The simplify tag has no wiki summary.
18
votes
10answers
2k views
What are the existing solutions to automate generalisation/simplification of geographical data?
I am looking for existing solutions (softwares, libraries, methods, etc.) to automate the generalisation/simplification of geographical data as presented there, and also there.
How do you proceed ...
17
votes
5answers
962 views
Simplifying geometries (generalization)
What are the recommended ways of simplifying geometries? Keeping in mind projections, and simplifying state geometries for example.
I've heard about converting to an 'equi-distant' projection that ...
13
votes
3answers
822 views
Best practices for visualising clustered features in web maps?
I'm looking for the best symbol to display clustered features in the ArcGIS Server JS API.
I don't like the "fly-out" animated cluster symbol, as used in the Silverlight API clustering or the JS ...
11
votes
4answers
2k views
Simplifying adjacent polygons
I encountered a problem simplifying set of polygons that are adjacent. If I simplify each polygon separately with the Douglas–Peucker algorithm (which is used by many open source tools), the resulting ...
10
votes
4answers
712 views
Large shapefile to raster
I have a large shapefile (1 gb) and need to rasterise it. I have tried the following already.
1.) Import it into GRASS using v.in.ogr this failed with the error message: ERROR: G_realloc: unable to ...
10
votes
3answers
935 views
Meaning of Simplify's tolerance parameter
The standard parameters of Douglas-Peucker's simplify algorithm are geometry and tolerance (e.g ST_Simplify in PostGIS). What's the meaning of the tolerance parameter? I know that the bigger the ...
10
votes
4answers
2k views
Simplifying polygons to linestring
I would like to simplify some polygons that represent rivers into linestrings. I assume that holes in polygons can be omitted. Anybody has some good idea how to simply do it?
It would be nice, if it ...
10
votes
3answers
538 views
How to simplify a routable network?
I have a network graph that I need to simplify in the sense of reducing the number of edges. The idea would be to merge nodes that are located close together and remove the connecting short edges.
...
7
votes
1answer
358 views
How to Simplify a Line Network Preserving Topology?
I have a Shapefile (consisting of European major roads) with about 250.000 Segments which I have to simplify for pgrouting. But I can't seem to find a way to do that properly.
This is what it looks ...
6
votes
1answer
347 views
How to use simplify()
i have my Vector Data saved in a PostgreSQL PostGIS enabled Database.
The Data im displaying is very detailed, i want to simplify it through the simplify() method of Postgis.
I duplicated one of my ...
6
votes
1answer
80 views
Finding Ring Smaller than a certain tolerance
In Simplifying a shapefile for world timezones
http://efele.net/maps/tz/world/
all generalize/simplify algorithms fail on 5 countries/states, shown in this shape file
...
5
votes
1answer
629 views
Why do simplify polygon results differ between ArcGIS and PostGIS?
I am mainly interested in why and how the Simplify Polygons tool in ArcGIS handles the simplification process, including preventing and resolving topological errors better than the equivalent ...
5
votes
1answer
446 views
Help simplifying multipolygons in geodjango
I have a few multipolygons that have several hundred points in them. I'm looking to create less complex "thumbnails" polygons.
Naturally I'm attempting to use the simplify method, which is supposed ...
5
votes
1answer
111 views
Simplifying polygons made from binary rasters
I'm using MaxEnt to produce a species presence / absence raster layer. It works fine but I have to choose a cut off point for what constitutes presence or absence. As a result I end up with a lot of ...
5
votes
1answer
198 views
POSTGIS workflow for cleaning up a noisy dataset
I have a conservation dataset that im trying to simplify for the purpose of using it as a GML layer in openlayers, ie reducing the total shape and node count to quite small.
The data has issues: eg-
...
4
votes
2answers
1k views
Simplify Raster Contours ArcGIS 10
Does anybody know a way to simplify a number of contour polylines derived from a raster dataset? I need to generate a map that shows contour polylines at relatively small scale. With the contour ...
3
votes
1answer
572 views
Changing the scale (generalisation) in ArcGIS 10
I have 2 polygon layers, accordingly 1:10 000 and 1:500 000.
I want to generalize the first layer from 1:10 000 to 1:500 000.
I tried using Simplify polygon tool, and since these scales relate to ...
3
votes
1answer
115 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 ...
3
votes
0answers
25 views
Reduce level of detail for vector contour lines [duplicate]
Possible Duplicate:
Simplify Raster Contours ArcGIS 10
I have quite a huge shapefile storing vector contour lines: 1GB. I want to create a detailed heightmap for further 3D usage but the ...
2
votes
1answer
459 views
Geometryutil, simplify polygon, querytask and query fault error
One of the tools in my app is to draw freehand polygons (counties) to show points (companies) in each county. Everything works great but if the user creates an intersecting polygon then I have a ...
2
votes
1answer
289 views
Redistribute linestring vertices to specified distance
I use a groundwater model program called GMS, and it has a very useful function "Redistribute vertices" (more info). I use this function all the time to both simplify and provide regular spacings ...
1
vote
2answers
38 views
simplify point geometry
I have a great amount of points and I need to show them on map. I am using OpenLayers. Is it possible to simplify point geometry in order to speed up the process of rendering?
1
vote
1answer
103 views
in QGIS, while using simplify feature, slider does not appear
Using Qgis both 1.8.0 and 1.7.4, the slider does not show up after selecting features and click "simplify feature" botton.
Any special setting needed to show the slider?
Thanks.
1
vote
1answer
47 views
Why won't lines from GPX simplify/generalize/smooth?
I am working with GPX data. I imported them to ArcGIS by 'GPX to feature' and then I created lines from these points. I am trying to smooth (or simplify) the lines now, but the tools 'smooth line' and ...
0
votes
0answers
61 views
QGIS - “simplify objects”-Tool not working any more after update
I updated QGIS (Mac-Version) on the newest version (1.8.0) since the older version crashed when adding a map-layer from openlayers plugin. This works now but the "simplify objects" tool doesn't work ...
