A type of cartographic generalization in which the important characteristics of features are determined and unwanted detail is eliminated to retain clarity on a map whose scale has been reduced.

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12
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5answers
1k 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 ...
1
vote
0answers
406 views

How do I smooth edges of polygons in QGIS?

Is there a built in function or plugin I can use to achieve smooth lines for my polygons instead of the blocky ones I have now?
0
votes
0answers
83 views

Reducing point numbers in a certain area

We have a list of poi data in our database(Access mdb db), and we have a web service which serve data by a specified BoundingBox. However we found that the returned points are too close to another at ...
1
vote
1answer
369 views

Algorithm to move polygon nodes when simplifying

I want to simplify polygons that come from a raster analysis. In order to avoid overlap and gaps, I first convert my polygons to lines. The problem is that all algorithm are then keeping the two end ...
1
vote
0answers
118 views

Simplify by number of points in QGIS

I have a fairly simply question about something I just don't know how to do. I am aware you are able to simplify polygons in QGIS based on distance tolerance but my questions is, is there a way to ...
4
votes
1answer
522 views

How to maintain right-angles when buffering?

When buffering some polygons I am trying to avoid the curved buffered area like this: I'm trying to do thins within an FME workbench but if someone knows how its done in other software that would ...
0
votes
1answer
94 views

Simplify table of linestrings

I have a PostGIS table of linestrings representing a road network. I want to simplify the geometries such that only lines that connect road junctions are stored. At the moment the table has a large ...
20
votes
5answers
2k 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 ...
0
votes
0answers
135 views

Can I simplify polygons in QGIS by Size?

Just wondering if it's possible in QGIS to simplify polygons based on size? I've done it many times using the tolerance level to reduce the overall size however in this case each polygon cannot be ...
7
votes
2answers
668 views

Lossless Polygon Simplification?

Is there a standard/recommended algorithm for simplifying a polygon without shrinking any of its original boundaries? Right now I'm using TopologyPreservingSimplifer within JTS and running into ...
2
votes
0answers
537 views

Smooth, not simplify, lines features in PostGIS

I'm trying to automatically generate paths to place labels on that follow the shape of rivers, 4wd tracks and other very windy lines. At first I thought the st_simplify() function was the answer, but ...
2
votes
1answer
205 views

simplilfy geojson file [duplicate]

I have a geojson file, but it's way too heavy for the app I need to develop I'd like to know what alternative do I have to make it lighter. I was thinking about simplifying it's shapes, and also ...
17
votes
4answers
4k 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 ...
11
votes
4answers
3k 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 ...
1
vote
1answer
185 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 ...
1
vote
2answers
145 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?
4
votes
1answer
612 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
31 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
1k 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 ...
25
votes
10answers
4k 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 ...
1
vote
1answer
445 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.
6
votes
1answer
151 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 ...
9
votes
1answer
854 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 ...
7
votes
1answer
353 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- ...
14
votes
3answers
2k 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 ...
7
votes
1answer
456 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
810 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 ...