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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2answers
38 views

Simplifying Ways in OpenStreetMap Data

Is there a (current) best practice to simplify ways? I have found: https://github.com/podolsir/osmosis-simplifyways But besides not being alive, here ...
7
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1answer
80 views

How to anonymise a gps file?

Imagine you have a GPS trace that you want to make anonymous, in the legal sense. How would you do this? Is snapping to the nearest x distance and stripping out the time enough? Are there ...
1
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2answers
35 views

Cannot Select 'Input line or polygon vector layer' when trying to simplify Shapefile

I'm trying to simplify a Shapefile by opening it in QGIS, Go to the Vector menu, selecting Geometry tools, and selecting Simplify Geometries... When I do this I get a modal window that I can fill out ...
5
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1answer
57 views

Is there a difference in results between Simplifying a geometry by different projections?

We have geometries in a PostGIS database projected in srid 4326. We need to have these geometries simplified with ST_SimplifyPreserveTopology. My question is whether this geometry needs to be ...
0
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2answers
97 views

How to remove unnecessary vertices

I have over sampled polygons that I need to simplify, without changing the shape. basically, I want to reduce the number of vertices, by eliminating the ones that are useless and have the polygons ...
1
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0answers
43 views

Query to merge simplified polygons according to the map scale-factor

I'm trying to construct a view in PostgreSQL that simplify polygons according to the map scale-factor. Basically I was reading this thread ...
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0answers
39 views

QGIS - Simplification process creates a new polygon - how to avoid it?

I am trying to simplify a layer made of polygons. I have used different methods but the new simplified layer has a polygon which intersect with itself, thus creating a "new" polygon. Please see ...
0
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1answer
44 views

ArcGIS Raster To Multipoint Mac/OSX alternative

Is there an alternative to the ArcGIS Raster To Multipoint tool for Macs? The VIP thinning method is particularly of use. A comparative point cloud thinning/simplification tool to this would just as ...
4
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2answers
67 views

writeOGR with a spatialpolygon simplified by gSimplify

I'm using gSimplify (rgeos package) to simplify the geometries of a shapefile. The funcion works good, but now I can't write the output in a new shapefile. I tried some ways: writeOGR(simplyshape, ...
2
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1answer
154 views

How to fill a hole - with islands within?

In QGIS I have simplified a layer. At the end of the simplification process (using GRASS v.generalize), my final layer "lost" a polygon: see white space in image: How can I recreate a polygon which ...
1
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1answer
41 views

simplify tiled geometries while preserving anything on the edge

I have a dataset of polygons split into evenly sized tiles. How can I go about simplifying them, but not along the tile edges, so that there aren't any gaps between continuous features when the tiles ...
0
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1answer
76 views

What is the best way to get simplified UK boundary data?

I have some recent data that is at the Lower Super Output Area (LSOA) level for Greater Manchester. I wrongly assumed that the data was for the latest LSOA boundaries, i.e. for the 2011 boundaries. ...
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0answers
19 views

Draw (adjacent) GIS-shapes, reduced and “rounded”

as the title says: I want to draw (C#, WinForms application) adjacent polygons stored in an GIS-database (SQL Server 2012, geography-datatype). The data source is OpenStreetMap administrative ...
1
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2answers
66 views

What is “Simplify tolerance” in QGIS's Simplify geometries tool?

I am trying to use QGIS 2.8 to simplify vector geometries. But I do not understand the significance of the Simplify tolerance value in the Simplify geometries tool. The documentation does not ...
6
votes
2answers
103 views

Complex Shapefile Compression Advice

I'm looking for some advice on how I can simplify this very detailed shapefile to ultimately be used for the web (as topojson) as a interactive heatmap. It was originally created from a raster file ...
1
vote
1answer
163 views

How Does Ogr2Ogr Simplify Work?

Can someone explain how the ogr2ogr simplify works? I am trying to use raster data which has a spectral resolution of 30m. The vector file that I am trying to import into Google Fusion is large in ...
2
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1answer
81 views

Collapse multiple lines into a single line

I need to create a route (line) feature class from another feature class that contains multiple lines making up the same route. pic 1 shows the original feature class with the multiple lines. pic ...
1
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1answer
71 views

Reduce number of points, keeping most recent data within a given distance

I have a HUGE dataset of points that were collected along a route. The data may change daily, and the most recent data is the most important. What I would like to do is take only 1 point from a given ...
0
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1answer
65 views

Simplifying polygons in ArcGIS considering contains-one-point topology rule?

I want to simplify polygons using the "Simplify Polygon (Cartography)" tool in ArcGIS 10.2. Additionaly there is one point in each polygon and this condition should still be fulfilled after ...
2
votes
1answer
114 views

Simplify a polygon dataset with a minimum distance between the new vertices

I would like to simplify a polygon shapefile where the resulting output has a minimum distance of 5 kilometres between the new vertices. We have ArcMap 10 on an ArcView license, FME and QGIS. I have ...
1
vote
1answer
120 views

QGIS 2.6 simplify a road network to obtain the intersections

In QGIS 2.6.1 in Ubuntu, I want to measure the density of block in this city (FYI my final aim is to measure the TOD level). I have the road network from French national IGN dataset BDTopo. I have ...
3
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0answers
71 views

How to simplify polygon shapefile and maintain topology? [duplicate]

I'm looking for a straightforward answer that actually works...not a 'duplicate question' flag. None of the other solutions posted in similar threads actually work...they all have dead-end answers ...
0
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0answers
27 views

ITopologicalOp simplify

I want to simplify a polyline geometry so that at the intersection line was torn, that is added EndPoint (see figure below). Polyline Feature class is stored in a file geodatabase in the dataset, it ...
2
votes
1answer
183 views

Why are my polygons automatically simplified/generalised when merging them in ArcMap 10.2?

I am creating a small land use map, as an exercise for visual image interpretation. I created a shapefile and started digitising polyogons with the polygon tool. The problem is that some of my ...
2
votes
1answer
123 views

Shapely's simplify won't simplify any more

I have a multipolygon in shapely, and I want to simplify it until it has less than a certain number of points. When I use the preseve_topology=False argument to geom.simplify, I can get the number of ...
1
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1answer
69 views

Generalize lines with specific points

It's been a while since I was here. I have this problem now. I have electricity line feature class and point feature class intersecting line features. What I need to do is simplify this line feature ...
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votes
1answer
103 views

How can I find a Douglas-Peucker algorithm for simplification? [duplicate]

I want to understand simplification methods in GIS. I searched the Internet and found that the best simplification method is the Douglas-Peucker algorithm. I could not find any information about the ...
1
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0answers
32 views

Keep synchronization when simplify features from different data source

We have two shapfile data source: 1 water-riverbank.shp With geometry type of Polygon which stands for the area of water 2water-riverline.shp. With geometry type of LineString which stands for ...
4
votes
1answer
268 views

ogr SimplifyPreserveTopology does not keep the Topology

I use ogr2ogr to simplify a layer of polyline, from the document: -simplify tolerance: (starting with GDAL 1.9.0) distance tolerance for simplification. This method will preserve topology, in ...
0
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1answer
97 views

Simplify polyline with the intersection point kept

I have a some line and polygon features which consist of too many points, so I tried to simplify them. I found the "Ramer–Douglas–Peucker algorithm". I think it will work well for a single feature ...
1
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0answers
214 views

How to import large features to Google Fusion Table from KML?

I am trying to import rather large features to Google Fusion Table from KML files (I have also shapefiles). However, Google has a certain limitation: "a cell of data in Fusion Tables supports a ...
6
votes
1answer
295 views

Competing approaches to line & polygon simplification

There seems to be a few theoretical options around at the moment for geometric simplification. Douglas–Peucker seems the most established, followed by Visvalingam's approach (used by d3.js). Now ...
2
votes
2answers
151 views

How to simplify streets such that seperate driving tracks are reduced?

Streets in Openstreetmap have more detail than I need. For instance I do not need seperate street tracks for each driving direction, instead I just want to show the general path of the street. ...
1
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0answers
308 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
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0answers
75 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
2answers
107 views

How to disable “Simplify geometry” via Python?

After I've loaded a layer from a table in my db I'd like to disable the 'Simplify geometry' (found in Layers/Properties/Rendering) programatically using Python. I've tried several versions of ...
1
vote
1answer
301 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
95 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
371 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
90 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 ...
0
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0answers
118 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
542 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 ...
1
vote
1answer
144 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 ...
2
votes
0answers
444 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 ...
1
vote
1answer
171 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
141 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
497 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 ...
5
votes
1answer
456 views

Simplifying polygons made from binary rasters using ArcGIS Spatial Analyst?

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 ...
3
votes
0answers
30 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 ...
1
vote
1answer
424 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.