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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2
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1answer
38 views

Generalizing (simplifying) polygon shapefile or feature class in ArcMap while preserving topology?

I came across How to generalize a polygon file and maintain topology in QGIS? which asks for a QGIS solution to my exact question. I'm trying to do this in ArcMap. I start with a polygon shapefile ...
1
vote
1answer
104 views

PostGIS: How to dissolve vector data

I have a few scenarios where I need to dissolve vector data, and I'm wondering how to do this using PostGIS. What would the queries look like to perform these operations? Below I'll describe the ...
1
vote
1answer
121 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
73 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 ...
0
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1answer
95 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 ...
5
votes
0answers
220 views

How do I simplify the straight sections of (multi)Linestring in PostGres/PostGis leaving the curved sections untouched

I have (multi)linestrings containing upwards of 5000 points and I want to perform two simplifications possibly using Ramer Douglas Peucker or alternative methods in PostGis The (multi)linestrings ...
2
votes
0answers
36 views

C/C++ function to return minimum set of points required to represent a geometric shape

I am looking for a method from Grass, GEOS, or similar that will delete those points in a geometry which do not affect its shape. Example 1 +----+----+ p0 p1 p2 p1 can be deleted without ...
2
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0answers
40 views

Combine files in TopoJSON when one is simplified differently to the other

I have two .shp files, I am separately converting these to GeoJSON with ogr2ogr.exe and then combining the files with TopoJSON. Each file independently becomes a ~200kb topojson file, however the ...
2
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0answers
576 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
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0answers
20 views

Filtering Small Areas of Shapefiles Using R

I'm trying to use the method proposed by the @ialm in the Question "How to speed up the plotting of polygons in R?" There, he loads the maps using getData from the raster package, I tested and it ...
1
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0answers
18 views

How can I use ST_Contains/ST_Overlaps with non-simple lines?

Following the SQL of the accepted answer to How to get smallest line segments from intersection + difference of multiple overlapping lines? copied below. I'm having some difficulties assign the ids of ...
1
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0answers
31 views

ogr2ogr (or other) simplification of polygons with shared boundaries

I am trying to simplify a collection of 100,000 or so polygons containing nearly 4 million vertices. The data is stored in a 2GB shapefile so there is no explicit representation of the topology ...
1
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0answers
52 views

Resolve Building Conflicts - the open source way?

In ArcGIS there is a tool called Resolve Building Conflicts and I'd like to achieve the same using only open source tools (QGIS, GDAL etc), preferably on Mac OS instead. In the long run I'm trying to ...
1
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0answers
82 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 ...
1
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0answers
46 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 ...
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 ...
1
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0answers
365 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 ...
1
vote
0answers
441 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?
1
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0answers
125 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 ...
0
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0answers
15 views

How to calculate tolerance for TopologyPreservingSimplifier in JTS?

I am trying to simplify some areal geometries (POLYGON\MULTIPOLYGON) using JTS's TopologyPreservingSimplifier.simplify(Geometry geom, double distanceTolerance) From the JavaDoc: void ...
0
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0answers
24 views

Can GeoServer be asked to clip a WFS response?

I'm fairly new to GIS, so I'm not very familiar with all the terminology and standards. What I need is a webservice that returns geographical polygons (countries and administrative regions) as ...
0
votes
0answers
29 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 ...
0
votes
0answers
90 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 ...
0
votes
0answers
148 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 ...