Generalisation is the simplification operation applied on spatial data when their representation scale decreases.

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6
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0answers
219 views

GeoServer pregeneralized layers not working as expected

I've set up GeoServer 2.1.4 and installed the feature-pregeneralized-2.1.4.jar plug in and processed my shape files into each of their separate folders with the generalized shapefiles and I've check ...
15
votes
2answers
2k views

How to generalize SpatialPolygons and conserving topology in R?

I would like to generalize a SpatialPolygonsDataFrame in R to make plotting more efficient. The polygons I have result in huge pdf plots that are slow to load and hard to integrate into a document. ...
6
votes
1answer
153 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 ...
15
votes
3answers
16k views

How to smooth/generalize a polygon in qgis

Is it possible to smooth or generalize a polygon in qgis? Ìs there a plugin available like the generalizer-plugin for lines? I could convert my polygons to lines, smooth them and convert them back to ...
8
votes
2answers
2k views

Raster generalization - buffers in rasters, expand pixels?

Is it possible to create buffers for pixels of raster files? Actually I need to expand the pixels classified as 1 (in white in the figure) with a spatial range of 1 or 2 pixels, in order to perform ...
7
votes
4answers
1k views

How to aggregate detached polygons?

Is there any open-source library to aggregate detached polygons? I know that there is a tool in ArcInfo, but it is commercial.
4
votes
1answer
1k 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 ...
2
votes
1answer
992 views

Why does aggregate polygons consistently error out?

I'm using aggregate polygons on a dataset with three large study areas. It did not work. So I split it into separate areas and did it again. Two of the three areas (which were smaller than the third) ...
3
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2answers
314 views

Need an explanation on a network simplification algorithm

I try to implement the algorithm described in this paper (page 8), but there's a place that I can't understand, and the authors do not provide a more detailed explanation or pseudocode. They show how ...
26
votes
5answers
3k views

Generalizing polygon file while maintaining topology in QGIS?

I have a polygon Shapefile, which I need to generalize. How can I generalize the poligons and ensure that there are no topological errors like "slivers". I already tried: Vector -> Geometry Tools ...
3
votes
1answer
359 views

Is it possible to simplify orthogonal polygons with OpenCarto Java Library?

I want to know if simplification of orthogonal polygons can be done with OpenCarto Java Library. If yes, does it have any API documentation? Cheers, Sanjeewa
9
votes
1answer
664 views

Why does GRASS eliminate polygons when using v.generalize?

I am facing a dilemma while trying to use v.generalize to simplify polygons which are similar in size and structure to US Counties or States. Often, I lose polygons from the data set after running ...
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 ...
11
votes
4answers
487 views

How to generalize coastlines?

I have a large set of data points that essentially represent the coastline of the world. I don't know the exact resolution but I'd say it's in the neighbourhood of 5-10m. Imagine a set of points ...
9
votes
3answers
181 views

Understanding location storage and query algorithms?

One of the most important aspects of a GIS-equipped database is that it provides the user with the capability to quickly query for all points within some arbitrary geographic area that match some ...
33
votes
3answers
16k views

What raster smoothing/generalization tools are available?

I have a DEM that I would like to smooth or generalize to remove topographic extremes (chop off peaks and fill-in valleys). Ideally, I would also like to have control over the radius or level of ...
6
votes
1answer
100 views

Dividing the world space to geographic sub-space

I am trying to divide the world space to geographic sub-space from "general" to "specific" locations and without using latitude and longitude information. That is, I am trying to think about the world ...
13
votes
2answers
1k views

Using “Merge Divided Roads” tool with lesser parallel lines

When using the "Merge Divided Roads" tool, it merges roads that "trend generally parallel to one another". This means that from figure one.. It will merge the beginning, where the roads are close to ...
5
votes
2answers
2k views

Tracklogs to single line OR several lines to one line?

Setting: I have several trucks driving out of my factory delivering goods and coming back for more deliveries. These trucks are equipped with GPS so that they may return tracklogs to me. These ...
4
votes
4answers
321 views

Enlarge/roughen the Vector Size of Tiles

Im currently running a GeoServer and my task is to make the vectors rougher thant they are right now. I really dont know where and how the Geoserver processes the data from the DB and how it will be ...
8
votes
3answers
1k views

Retrieve polygon smallest MBR

I have a postgis table containing polygons. I want to transform my polygons to 4 points polygons : retrieve the smallest MBR. Here comes an illustration of what I want : My original polygon is ...
19
votes
4answers
4k views

Generalisation Strategies for Building Outlines

I have a dataset of building footprints vectorised from a raster dataset. The dataset is currently just a vector representation of the raster data. I would like a polygon dataset that only has ...
9
votes
2answers
1k views

Combining high resolution and generalized hillshade rasters to produce enhanced shaded relief?

I often add LiDAR data to a map along with a shaded relief. Most of the time I have to generalize the LiDAR DEM depending on the scale of the map. Still, there is often too much detail and mountain ...
16
votes
5answers
2k views

Rendering overlapping lines

I am making a map containing information about public transportation: busses, trams, etc. The map will have a layer containing for example the tram lines. Each line has its own colour, and is ...
25
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10answers
4k views

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. Do you know and use ...
20
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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 ...