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Questions tagged [dissolve]

To merge features based on specified attributes.

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100 views

Buffering with dissolve type: ALL for a big feature class doesnot create a single multipart feature

I am using buffer tool on large complicated network (260,000 features) line shapefile to create an area shapefile. This area shapefile somehow has to be dissolved to a single multipart shapefile. ...
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1answer
214 views

Dissolve polygons in Spatialite - New Table has no Geometry

I have followed some examples for dissolving polygons in Spatialite and successfully created my simpler polygons: SELECT "col1" sum("total") AS "total", st_union("GEOMETRY") AS "GEOMETRY" FROM ...
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0answers
136 views

Is there an equivalent to the Dissolve all function in GDAL dissolve user interface? [closed]

I am looking to compare the speed of the dissolve tool because the QGIS dissolve tool is performing very slow for me. However, I need to dissolve all the features into one so that I can create an ...
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0answers
59 views

Using Intersect and dissolve to divide district into certain regions with data of interest without losing spatial data in ArcGIS Desktop?

I am using an intersect/dissolve feature workaround in ArcGIS Desktop 10.5. I have a layer of districts of a city and another layer of parks in the whole city /layer of noise amount around big ...
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0answers
19 views

Finding parcels which combine to create largest area

I have a shapefile of 500 polygons and I need to find the 22 neighboring polygons that when combined will produce the largest continuous area. Does this involve the Dissolve tool? What do I ...
2
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0answers
272 views

geopandas dissolve versus postGIS postgresql aggregated groupby dissolve

I have a geodataframe for which I want to dissolve the geometry based on an attribute (fao_id). In geopandas this is easy as gdf.dissolve(by="fao_id", aggfunc="first") but unfortunately this fails due ...
0
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1answer
119 views

Cannot Dissolve this Shapefile

QGIS 2.18.11 This is not a question as such, but certainly something which I would learn from if resolved. I have uploaded a shapefile of polgyons from multiple layers all merged into one. I have ...
2
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1answer
188 views

arcpy dissolve throws error 000369 in already successfully tested script

So I'm running a simple line FC through this: # geh = inputFC # fields = ["list","of","fieldnames"] def clause(fields,br_cl_val): clause = """{0} = {1}""".format(arcpy.AddFieldDelimiters(geh,...
2
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1answer
260 views

Dissolve by group and get the lowest or highest in other field

I've got the next table of attributes: I want to perform a dissolve by the first column (date) and get: - Earliest value by group in the second column. - Latest value by group in the third column. ...
0
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1answer
365 views

How do I aggregate multi-part features based on a field value?

I have a city park layer that has several multi-part features. I would like to dissolve these into single part features using the Aggregate Polygon tool. I cannot use the Dissolve tool because most of ...
1
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1answer
388 views

How do I create a dissolved buffer using PostGIS with EPSG 4326?

I'm trying to buffer a polyline (WGS84/EPSG 4326) by 50km, and then dissolve all the overlaps in the buffer. So far I've tried a combination of: casting the EPSG 4326 geometry as geography (to get ...
1
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1answer
94 views

How to delete roads within blocks using ArcGIS? [closed]

I want to delete all the internal roads which exists in Block2. These roads don't have any attribute data. It is a single polygon. I need to extract only external roads. Block 2 should be made as ...
2
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1answer
548 views

How to create dissolved buffer layer with pyqgis?

I have a line vector layer with a field name of "buffer_distance". I want create a dissolved buffer layer based on it's field. I write below code: from qgis.utils import iface from qgis.analysis ...
1
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1answer
78 views

Combining polygon file with multiple overlapping polygons to represent only 1 attribute in given area e.g. highest/lowest/average in ArcGIS Desktop?

I have a large shapefile that I'm working with in ArcGIS 10.5 with an ArcInfo license. At any given location in the file there are multiple polygons. In the example I am working on there is a ...
3
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0answers
341 views

Dissolve fails, geometry errors, and cleaning problems

I fairly new to GIS, and I'm having an issue with dissolving a vector. To start, I'm running QGIS 2.14.15 on Windows 7 Pro. When I try to dissolve the polygons it creates a blank shapefile. All of the ...
1
vote
1answer
94 views

Creating outline around layer which has separated features using ArcGIS Desktop?

I have a layer representing a neighborhood. And the roads are separating groups of features(blocks) from each other. I want an outline around the whole neighborhood and not around each feature or each ...
3
votes
1answer
1k views

Dissolving only selected features in a layer?

I am curious to know if it is possible to dissolve only the selected features in a layer in QGIS. In ArcGIS this is the default behaviour (which was actually someone annoying most of the time), but ...
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0answers
763 views

Dissolving complex polygons using PyQGIS?

I have a workflow to eliminate small polygons within a layer and merge them with adjacent polygons. My input is the result of a polygonization of a raster (has no overlaps) and it has one field "class"...
0
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2answers
99 views

Merge polygons separated by road spaces while keeping the boundaries of separations

I made a Merge of cadastral parcels to have localities. The problem is that I have the polygons of 6 localities but with voids/spaces in the middle that represents roads. I would like to merge/union ...
0
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1answer
354 views

Dissolve Leaflet VectorGrid polygon at tile boundary by ID

I am using Leaflet and the Leaflet.VectorGrid plugin to display vector tiles on a map. My vector tiles contain Polygons that render fine, except that they are also rendering the split at the tile ...
4
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1answer
1k views

Group and union polygons that share a border in R

I am attempting to union all polygons that: 1) share any portion of a border, or 2) have within a certain threshold distance (e.g., 50m) of each other, within a SpatialPolygons object. for_cov_sp_0 ...
4
votes
1answer
721 views

Permanent attribute join (for dissolving)

I am quite new with QGIS and I have run into a problem that I would love your suggestions to. Here we go: I want to end up with a municipality map with the sum of perish population. Here's what I ...
3
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0answers
56 views

After dissolving lines, old node/vertex order does not reset, causing issues with chainage

In QGIS, I am trying to dissolve multiple segments of a river feature and then calculate chainage on the resulting single feature. However, it seems like the internal node/vertex order gets preserved ...
2
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0answers
44 views

Dissolve in QGIS to merge several processes in different regions into one process with all values

I am working on a dataset where I combined geographical information of cities in Europe and changes of landcover in these regions. I am working with the CORINE Dataset and I would like to know about ...
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1answer
115 views

QGIS: Looking for an 'Update' function similar to ArcGIS

I am doing an analysis of a road network. The attribute table holds information on the road name, type (e.g. A road, motorway etc). I would like to group all the minor roads as a single field. I ...
2
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0answers
48 views

Dissolving polygons based on spectral differences from QGIS?

I'm looking for a package or algorithm that allows to dissolve polygons based on their spectral characteristics and a threshold defined by the user in QGIS. Equivalent to what the "Spectral ...
4
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2answers
267 views

Dissolve with expression in QGIS

I have a shapefile with polygons containing UK postcode units, example SL1 1AA. I want to dissolve these into postcode sectors,example SL1 1. I can use this expression in the filter to get all those ...
1
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1answer
864 views

Dissolving all overlapping, intersecting, touching polygons on single layer using QGIS?

I'm quite new to Qgis and have a problem which is easy to solve, I think. I've done research for hours but did not succeed. I have a data set which contains thousands of polygons in one layer. What I ...
3
votes
1answer
399 views

POSTGIS Dissolve operation not working properly (ST_union)

I want to dissolve a polygon data set in POSTGIS. So far I've read about some different approaches, e. g. Is there a dissolve function in PostGIS other than st_union? When I run one of the following ...
0
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1answer
102 views

Dissolve does not fully dissolve lines

I dissolved a polyline feature (streets) on the following fields: WHOLESTNAM, NUMBEROFLANES, THOROUGHFA, SPEEDLIMIT, GEOID and asked the dissolve to take an average of the AADT field. Why does the ...
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0answers
79 views

Accessing Polygons of Dissolved Layers in QGIS [closed]

I've been trying to access the polygons of a dissolved layer in QGIS, and every time I query them, I get an empty polygon back. My procedure is as follows: I start with a layer of polygons, and use ...
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0answers
50 views

Removing Polygons Within Polygons After Merge (QGIS 2.18 OS X)

I've merged together a polygonized raster layer of a certain elevation grade (>25%) and a wetlands buffer. I can't seem to find a good solution to the problem at hand, however. Ultimately I'd like to ...
2
votes
1answer
145 views

Dissolving polygon with enclave does not work

i tried to dissolve two polygons(brown and the yellow marked polygons) of one layer that own some en-/exclaves in QGIS (first union both, then dissolve the union-polygon). But dissolving dose not ...
2
votes
2answers
138 views

Dissolving/connecting discontinuous Sewerage network using ArcGIS Desktop?

I am using ArcMap/ArcGIS Desktop 10.3. I have a sewerage network that is cut at specific locations and I would like to have a continuous network while retaining the different segment because they ...
2
votes
1answer
506 views

Dissolve ogr geometries in Python [closed]

I parse a geoJson file resulting in a list of osgeo.ogr.geometry-classes (all Polygons). I also have a new one which I want to dissolve with the rest. I'm using the ogr package in python, it does ...
2
votes
1answer
213 views

QGIS Dissolving and holes [duplicate]

I am using QGIS 2.18.9 and I have a problem. I dissolved a small map with about 1000 small regions into one big polygon, with Vector->geoprocessing tools->dissolve. But after the dissolving ...
1
vote
1answer
431 views

Dissolving while retaining attributes?

So I have a point shapefile, with each point representing a bus stop. The shapefile contains a separate stop point for both sides of the road, which I want to consolidate into one point. So first, I ...
4
votes
1answer
370 views

Dissolving reprojected features split into two parts by international dateline (180 degrees) in QGIS

I am trying to view the World EEZ polygon from Marine Regions.org, but centered on the Pacific Ocean. To centre the EEZ map on the Pacific ocean I followed these steps. The custom CRS from this ...
2
votes
1answer
339 views

Polygons not merging in QGIS when dissolving?

I am new to QGIS and am trying to dissolve polygons in my shapefile using one of the fields in the attribute in QGIS 2.8.5. The process runs, and it does add a new map but nothing seems to have ...
2
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0answers
643 views

PostGIS: ST_Union fails with valid polygons?

I am working with this dataset. I have imported it into a Postgres 9.6 database with shp2pgsql as follows: shp2pgsql -I -s 5070:5070 us_govt/PADUS1_4Fee.shp usgovt | psql -d mydb I have made all the ...
2
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0answers
59 views

Merging features in layer AND calculating geometry for newly merged features in ArcGIS Desktop? [closed]

First, I'm working in ArcMap 10.3.1 I have many layers which are made up of multiple features (polygons). I want all those polygons to be merged into one. First I tried dissolving the layers, but ...
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0answers
269 views

How do I remove the boundaries between municipalities of my shapefile?

I have a shapefile of a province right now. It includes the barangay/village boundaries and municipal boundaries. However, I only need the municipal boundaries. How will I remove the barangay/village ...
1
vote
2answers
104 views

Deleting traces after dissolving several polygons in ArcGIS Desktop?

I'm using ArcGIS 10.4. I have a shapefile that has many catchments in it. I wanted to dissolve all these catchments to get just the boundary of the study area. I used dissolve to do so The problem ...
5
votes
1answer
194 views

Finding centroid of point pairs based on common ID using ArcGIS Desktop?

I want to take a series of point pairs within a single shapefile and find a single centroid point for each pair. For example in the image below, I would like there to be one point "31", one point "32"...
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0answers
525 views

Dissolving adjacent polygons in R? [duplicate]

I would like to dissolve only polygons that are adjacent to one another. Ultimately I would like to start with a raster representing landscape patches and delineate the separate patches. Here is my ...
2
votes
0answers
45 views

Holes between polygons after dissolve [duplicate]

I’ve got a shapefile of Switzerland. Shown Polygons are 6-digit ZipCodes. Whenever I dissolve the file for example by 4-digit ZipCodes, it results in incorrect polygons. Unfortunately some polygons ...
0
votes
1answer
102 views

Preventing GDAL-dissolve from ignoring attribute encoding?

Given a huge shapefile which needs desolving by one attribute field to reduce redundancy. The GDAL dissolve functionality does that quite swiftly but the output attributes change the encoding so äöü ...
2
votes
1answer
108 views

Converting a Multipart Polygon to a Single Line

I am dealing with a multipart polygon shapefile of Canada, where each province is its own polygon. Simply for cartographic purposes I want to display the provincial boundaries as a dashed line but ...
3
votes
1answer
298 views

Dissolve adjacent parts of multipolygon into a single Polygon

I have a multipolygon with two parts: I want to erase the line that separate both parts and get a single polygon that looks like this: I don't mind if I do it in QGIS or in Postgis, but it has to be ...
4
votes
1answer
1k views

Merging adjacent lines in QGIS

In QGIS, I want to merge features lines that same attribute value and are adjacent. What characterizes a line to be adjacent to another is the final vertex of a line to be coincident with the initial ...