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Questions tagged [generalization]

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1answer
97 views

Problem with low quality tiff

I have the problem with low quality raster. Now it looks like this: a busy cat http://iv.pl/images/53039057684486451032.png I would like to change this to looks like this: a busy cat http://iv.pl/...
3
votes
1answer
114 views

Generalizing exact location of certain data points using Carto CSS?

I am dealing with some sensitive data for which providing a high resolution of accuracy of the location would be detrimental. However, the general location is not sensitive and useful to share. I ...
3
votes
1answer
672 views

How to produce outline of a coastline?

I have polygon dataset containing quite a complicated coastline. How can I produce an outline of that coastline? Please see the image: my dataset is in green and the coastline I need to get is in ...
2
votes
1answer
107 views

Creating fishnet from thematic polygon data?

I need to create a regular grid containing attributes from other thematic data from ecological data. I am in effect creating a homogenous polygon raster and adding information from another dataset ...
1
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0answers
141 views

Combine two parallel lines to one with postgis [duplicate]

In OpenStreetMap, a highway=motorway consists out of two parallel lines, each representing one direction: On a professional map the two lanes get combined to one single line and drawn with a middle ...
1
vote
0answers
212 views

QGIS: automatic generalization

I'm trying to generalize my line features with QGIS. I've tried the "Generalizer"-Plugin, but can't get the results i want. I'd like to generalize my line as shown in the image. I've tried the "...
2
votes
2answers
707 views

Collapse dual lines to centerline doesn't exist in ArcGIS Pro?

I have ArcGIS Pro build 3308 (Ver. 1.1) and wish to collapse two parallel lines into one, however it appears that this function no longer exists - I have also tried using python for this and received ...
4
votes
2answers
11k views

Removing 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 ...
3
votes
1answer
1k views

Collapsing multiple lines into 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 2 ...
0
votes
1answer
181 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 ...
0
votes
1answer
528 views

How to set a maximum amount of features to be drawn in every zoom level

I want to apply a form of generalization/specialization to my OpenLayers map. Is there a way to set the amount of WFS features to be rendered based on the zoom level? In GeoServer you can set the ...
8
votes
1answer
209 views

What do you call this non-hole edge condition?

After generalizing or simplifying polygons, you often get legitimate holes in polygons, which are separate parts and can be filled. But what is the correct term for this triangular shape? It is an ...
1
vote
1answer
160 views

Geoserver (automatic labeling generalization) [closed]

I am a Master student looking to do my thesis in cartographic labelling using GeoServer. The thesis topic will be something like "Cartographic Labelling in Real Time Mapping using Web Services. I am ...
1
vote
2answers
50 views

How to find “empty” buffer?

So I have lines(road network) and buffers around them. I need to find "empty bufers" whose lines is missing (pic below). Lines have attributes of buffer width, but it is incorrect in some cases (does ...
2
votes
1answer
1k 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 ...
5
votes
1answer
2k views

How to reproduce Smoothing from Generalizer Plugin in v.generalizer in Processing Toolbar using QGIS?

I´d like to reproduce the smoothing operations done with the Generalizer Plugin inside the v.generalizer Toolbox so I can use them on a polygon layer instead of only on a line layer. I tried ...
7
votes
0answers
170 views

Alternative to Delete Polygons And Extend Lines of Production Mapping? [closed]

Maybe someone knows an alternative for the Delete Polygons And Extend Lines (Production Mapping) tool or a simple way to achieve the same result but without requiring a Production Mapping license?
1
vote
2answers
492 views

v.generalize on massive vector data

I have a contour line file that covers the most part of north italy (shape is 0,6 gb) and I want to use v.generalize (snakes algorithm) on it. Because of the large file size, if I use Grass 6.4.3 I ...
1
vote
1answer
335 views

How to simplify a multiline geometry in QGIS?

I'm trying to simplify my shapefile, which uses a lot of vertices to represent curvatures, by using the Generalizer plugin. But no matter what threshold I use for Douglas algorithm, it still includes ...
7
votes
1answer
3k views

QGIS equivalent to ArcGIS Aggregate Polygons?

I am looking for a tool in QGIS 2.40 that performs the function ArcGIS refers to as Aggregate Polygons. Basically it takes a group of polygons within a specified distance and creates a concave hull ...
1
vote
1answer
111 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 ...
5
votes
2answers
498 views

how to get a low level road network from openstreetmap data?

I've extracted the road network of a city from openstreetmaps (filetype: osm). One part of the road networks look like this: However, there are too many details in this data. I'd like to represent ...
6
votes
1answer
1k 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 ...
4
votes
1answer
2k 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 ...
9
votes
4answers
6k views

How to generalize a point feature class

I have a point featureclass with a point for every 25cm - in Total 400,000 Points. I would like to reduce this resolution to one point every Meter. How could I instruct ArcGIS Advanced(ArcInfo) to do ...
2
votes
0answers
217 views

Is there a way to build topology and work with topology relations in PyQGIS?

Is there a way to build topology and work with topology relations in PyQGIS? I'm asking because I need to run some custom generalization algorithms on my data, and I need to preserve topology. ...
4
votes
2answers
3k views

Merge point features within a given radius [duplicate]

I have a file in QGIS with 5000 points. Some of the points are really close to each other (5m). How can I cluster the point features to one point feature if they are within 5m? The new points should ...
3
votes
1answer
884 views

Flatten GIS data to a schematic

I want to take a network of roads and lanes and reduce them to a schematic that shows their relationships but not their geographic shape. A similar concept has been used for the London Underground ...
1
vote
0answers
58 views

Condensing sparse geocodes to weighted Geo-Circles?

I have a dataset comprising 3 million records having latitude and longitude information associated with them. I want to condense it to form few thousands Geo-Circles, with radius and weight depending ...
7
votes
6answers
2k views

Tool/Algorithm for generalizing OSM-Files for printing maps

Is there a tool or algorithm to (topological) generalizes OSM-shapes? I would like to build a printable map in different scales. In the image below you can see the same divided road (yellow) at ...
2
votes
2answers
423 views

How to smooth a raster in a rectangular fashion using gaussian blur?

How do I adjust the code for the Gaussian Blur posted in the thread: What raster smoothing/generalization tools are available? to retain the resolution/gradients in the y direction and blur only ...
1
vote
0answers
181 views

When digitizing Lines, vertices are automatically generalized when finished feature

I am creating lines(feature class) and when the feature is finished Arcmap 10 will automatically generalize/smoothens the line. Is there any reason why this is happening? is this a bug of ArcMap 10? ...
2
votes
1answer
323 views

filter / generalize elevation points on the basis of some conditions

I wanted to generalize many elevation points in a rectangular area (about 700 square km). I need to take about 3 points for square km. These points must satisfy some conditions: One of these ...
7
votes
2answers
6k views

Tips for minimizing shapefile size without compromising geographical detail?

I work for a state government's fisheries service, and lately we've been digitizing a lot of our regulatory boundaries within the state's waters that we'd like to service out on web maps. ...
6
votes
1answer
473 views

Raster aggregation in ArcGIS Desktop?

I'd like to aggregate a raster from 1m to 6m in ArcGIS with a custom rule. For example, each cell value of aggregated raster = mean value of 5 highest cell values from 36 aggregated values. How do ...
22
votes
3answers
10k views

Performing Raster Noise Reduction and Edge Smoothing?

I have a raster image like this I want to delete the isolated noise point and smooth the edge (say the white single points, and I want the edges of the entity look smooth). How can I do this in ...
7
votes
2answers
1k views

Using ArcGIS to filter cells where 7 or 8 of neighbors are different

I have land cover data that I would like to clean using some generalization tools. Majority filter does almost exactly what I want, but is missing one key option. Majority filter allows you to change ...
6
votes
0answers
332 views

GeoServer pregeneralized layers not working as expected [closed]

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 ...
18
votes
3answers
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
194 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 http://enclick.com/...
37
votes
5answers
53k views

Smoothing/generalizing polygon in QGIS?

Is it possible to smooth or generalize a polygon in QGIS, perhaps by using a plugin like the generalizer-plugin for lines? I could convert my polygons to lines, smooth them and convert them back to ...
12
votes
2answers
5k 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
2k 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
2k 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
2k 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
votes
2answers
413 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 ...
35
votes
5answers
7k 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
553 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?
9
votes
1answer
873 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 ...
15
votes
3answers
3k views

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 ...