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

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35 views

How to smooth “internal” polygon borders

This is my first foray into GIS and GIS software. I am using ArcMap currently. I have a shapefile of the world divided into different ecological regions. I would like to reduce the file size by ...
2
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1answer
255 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 ...
2
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1answer
1k 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) ...
1
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1answer
38 views

How are road polylines generalized?

I have a dataset of road lines obtained from digitized aerial imagery and I want to automate the generalization procedures using arcGIS model builder. I am using the ArcGIS 10.3 desktop suite. I have ...
4
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2answers
106 views

Removing unnecessary vertices at places with no change of direction?

I am aware that this question has been asked here: How to remove unnecessary vertices. I want to focus a different point. How to remove unnecessary vertices without changing the shape at all. As you ...
1
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2answers
2k 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 ...
2
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1answer
54 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 (...
8
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3answers
160 views

Why are the holes in my polygons not generalized?

I have one polygon layer with many holes. I would like to generalize it. I used v.generalize of grass. With it, I used chaiken algorithm. But, only the borders of polygons were generalized, the holes ...
27
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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 ...
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 ...
1
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1answer
49 views

How to do a Loop with a condition in Model Builder?

Can I loop a set of actions in model builder while a specific features rows are 1 or more. Some background: I have a point layer where I've created a workflow that: first selects the row with the ...
3
votes
1answer
66 views

Loop and perform loop in order depending on attribute

I have a lot of points in one layer. All of which represent the same type of real world feature. I want to perform a delete identical within XY of each point but in a specific order. (by splitting ...
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 ...
6
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0answers
226 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 ...
1
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1answer
44 views

How is width commonly defined for areal features?

Map generalization guidelines, for instance applicable to CORINE Land Cover or Polish BDOO databases state inclusion criteria for areal features like "area should be > 250 000 m^2 and width should be >...
5
votes
1answer
140 views

How to cartographically generalise buildings/settlements in QGIS?

I have a set of buildings in a polygon layer which I'm going to use in a 50k map. Since the buildings are tiny I cannot show the actual form of the building, instead I'm taking the centroid of the ...
1
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0answers
31 views

How to generalize a raster with noisy edges with ArcGIS Desktop?

I'm trying to generalize a raster to get clean edges (see sample and "optimal" result below). However the borders bleed into each other to a rather high degree. I hacked away at the raster using ...
2
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0answers
52 views

Avoiding edges using GRASS generalization?

I'm trying to process the national wide land cover data into vector polygons. In order to be quick I separate the data into several tiles and process them in parallel. process flow is : 1. v.in.ogr ...
3
votes
2answers
209 views

Simplify/generalize Polygons and keep topology of different layers PostGIS/QGIS

i have some polygons of a country, states, districts, communities and i want to simplify the geometry. i already simplified the geometry of each layer but afterwards of course it doesnt fit with the ...
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
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1answer
66 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 ...
1
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1answer
54 views

Problem with low quality tif

I have the problem with low quality raster. Now it looks like this: I would like to change this to looks like this: Im using ArcGIS, ArcScan. After some work with photoshop and reclassify with ...
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 ...
2
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1answer
89 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 red....
0
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0answers
43 views

Geological map generalization polygon aggregation

I am working on generalization of Geological maps and the first thing I am wondering about is aggregation of separate patches that may have same class and which are closely situated to each other. ...
9
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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 ...
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1answer
41 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 ...
33
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3answers
17k 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 "...
1
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0answers
55 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
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0answers
86 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
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2answers
162 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 ...
7
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2answers
719 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 ...
5
votes
1answer
297 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 ...
17
votes
2answers
6k 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 ...
1
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0answers
52 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 ...
3
votes
1answer
399 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 ...
0
votes
1answer
116 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
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1answer
90 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 Open Layers 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 ...
7
votes
1answer
140 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 ...
2
votes
1answer
213 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 ...
1
vote
1answer
91 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 ...
6
votes
1answer
332 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 ...
2
votes
1answer
513 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
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 ...
1
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2answers
36 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 ...
4
votes
1answer
909 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 ...
0
votes
2answers
172 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 ...
6
votes
0answers
131 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
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1answer
120 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 ...
15
votes
3answers
17k 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 ...