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Questions tagged [dissolve]

To merge features based on specified attributes.

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Remove internal lines within merged polygon

I am having trouble removing internal lines from within a polygon. I have tried to dissolve, and to use the GRASS clean tool, but the data source has some inherent errors so it doesn't work. Any ideas?...
samsamsam's user avatar
3 votes
1 answer
69 views

Dissolve neighbour polygons when distance is below X meters

I like to dissolve polygons in QGIS which are separated by small gaps (streets or paths...). As shown in the picture below, the two polygons in the north should be dissolved, excluding the one in the ...
BAE_23's user avatar
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2 votes
0 answers
58 views

Why are there so many slivers in my polygon shapefile?

I georeferenced a map and then traced a vector polygon shapefile over it, but when I dissolve it I am left with an enormous amount of slivers. All the vertices are snapped as far as I'm aware. What ...
MapDeath's user avatar
  • 343
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0 answers
15 views

Model designer QGIS question - Function toggles

I just recently started using the model designer and I was wondering if anyone knows of a way to switch between the paths the process goes through. As in some kind of toggle that would allow us at the ...
user238820's user avatar
3 votes
1 answer
200 views

How do I merge/dissolve two polygons within one shapefile in QGIS?

I have a shapefile composed of many polygons. I want to merge/combine/dissolve some adjacent polygons that I have selected within the shapefile into one polygon without any slivers or lines left in ...
MapDeath's user avatar
  • 343
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0 answers
27 views

Why new v.dissolve procedure generates new database tables and causes an error on adding columns later?

The new v.dissolve procedure includes, as the documentation states, two independent processes: v.reclass and v.extract, being a front end to those. In my case when v.reclass is called it creates a new ...
Nikolay Yasinskiy's user avatar
1 vote
2 answers
90 views

Dissolve only the smaller features among the larger ones

I want to dissolve features smaller than 1 ha among those larger than 1 ha. For example, if I have 2 features > 1ha and 1 feature < 1 ha, at the end of this process I would like to have 1 ...
Syner's user avatar
  • 31
0 votes
0 answers
71 views

Python Geopandas: Dissolve function does not dissolve overlapping polygons

I have developed a Python program using GeoPandas to handle overlapping polygons. The program first dissolves these overlapping polygons and then applies an overlay operation (specifically, ...
user2293224's user avatar
1 vote
0 answers
44 views

QGIS 3.22.16 Layout: how the Atlas displays only one ID at the time on the map

I am using QGIS 3.22.16. My goal is to create maps for each Tree ID. I used the Atlas tool and dissolved the tree layer. However, the atlas shows several ID trees on the same map (like Atlas image). ...
GIS Noh's user avatar
  • 321
1 vote
2 answers
105 views

GeoPandas Dissolve takes long time to execute

I have a dataframe in GeoPandas Python. The data frame contains around 3800 rows (geometry type is Multiplygon). Some polygons are overlapping each other. I want to dissolve those overlap. I used ...
user2293224's user avatar
0 votes
0 answers
21 views

Achieving ArcGIS Dissolve result with GeoTools

I want to merge two or more adjacent lines (within a XY tolerance) to one line. The result from Dissolve in ArcGIS is what I aim for. How can I do that in GeoTools? See figure below.
Paul's user avatar
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1 vote
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76 views

Achieving ArcGIS Dissolve result with PostGIS

I want to merge two or more adjacent lines (within a XY tolerance) to one line. The result from Dissolve in ArcGIS is what I aim for. How can I do that in PostGIS? See figure below.
Paul's user avatar
  • 477
0 votes
1 answer
56 views

Merging features on the same ID but other attributes combined [closed]

I have a layer with data: ID | Attribute1 | Attribute2 1 x b 2 x c 3 y d 4 y e 5 z f I want to dissolve ...
Lutu's user avatar
  • 31
3 votes
1 answer
1k views

GeoPandas error - GEOSException: TopologyException: side location conflict

I have a GeoDataFrame with fields: "Site","Group","Area", and "geometry" column with MultiPolygons. I try to unite rows based on the "Site" and "...
Omer Tzuk's user avatar
0 votes
0 answers
24 views

Problems with dissolved shapefiles in Google Earth Engine

I created a single dissolved polygon shapefile out of a set of smaller polygons in ArcGIS and imported it into Google Earth Engine using geemap (Python API). I wanted to extract values from every ...
Feesh's user avatar
  • 41
0 votes
1 answer
180 views

FME Form (Desktop) - Dissolver Transformer Generates Redundant Remnants

I have line geometry that I buffered with 50 feet buffer. Now I need to dissolve common boundaries for overlapped polygons, to reduce the size of the file in general. Source lines Buffer "...
Maria Savchenko's user avatar
1 vote
1 answer
116 views

st_union in R creates artifacts for global data

I load this polygon data in R which global coverage. https://drive.google.com/file/d/1E-atD4ZhbaQ8Zxv93sFgk9l_atLtG8eJ/view?usp=drive_link It looks like this: In QGIS I can run the dissolve function ...
Lenn's user avatar
  • 1,287
2 votes
0 answers
27 views

How to dissolve links and split by other links

I am trying to aggregate road network segments by intersection using QGIS. The blue route consists of 1000 links, and I want to aggregate this route into two segments. Ex: first and second segments ...
eun lee's user avatar
  • 21
0 votes
0 answers
23 views

Dissolve function for selected polygons in a layer in QGIS 3.3

Im using QGIS 3.3 and am trying to dissolve selected polygons in a layer. In the dissolve tool I am unable to select ' selected features only'. Even if i manually select the polygons and run the ...
Sanju's user avatar
  • 1
0 votes
1 answer
330 views

Dissolve multiple overlapping polygons into one polygon covering the extent for all such instances of overlapping polygons [closed]

I have a polygon layer in which some polygons are close to one another whereas some polygons are just alone and do not have other polygons in vicinity. So I created a 10 meter buffer, I want to keep ...
soumik chakraborty's user avatar
6 votes
1 answer
151 views

Limiting administrative shapefile to less granular level using ArcGIS Pro

I am using an administrative shapefile of Jamaica in ArcGIS Pro. I have a number of attributes at varying levels of granularity. There are 14 Parishes, 65 "Constituencies", roughly 650 "...
Matt's user avatar
  • 93
3 votes
1 answer
851 views

Using shapely unary_union() function to union polylines in ArcGIS Pro not behaving

I am developing an ArcGIS Pro 3.1.0 toolbox (atbx) and one of the tools I'm creating is selecting a set of polylines (which are river centrelines) and merging them into a single long polyline. ...
Hornbydd's user avatar
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1 vote
1 answer
678 views

How to speed up processing time when using geopandas dissolve() function?

I have a geodataframe with 8000 rows based on the joining and intersection of two geodataframes. One contains 8000 points and the other 12 polygons. See below the code used to join these two ...
Ben Watson's user avatar
1 vote
0 answers
294 views

Dissolve multiple polygons and keeping attributes

I am new to QGIS. I have vector data with many greenspaces in a city. I want to merge neigbouring polygons. I did this using dissolve which works fine (see below, brown before dissolve, green after). ...
Anouk's user avatar
  • 11
5 votes
1 answer
266 views

Creating virtual layer with extent of features from multiple layers in QGIS

I am trying to create an atlas that shows a series of plots (polygons) along with the access routes (line features). I need to vary the extent to show the entirety of each site along with the access ...
Brian Fisher's user avatar
  • 1,133
2 votes
1 answer
158 views

Creating new layer with custom regions from states boundaries in QGIS

I am trying to create a map where I can combine a layer of states boundaries and one other with custom regions (Est/West) on QGIS. So I have tried it in different ways (union, intersection, merge ...
foxhound's user avatar
2 votes
1 answer
440 views

Dissolving overlapping multipolygon geometries into new multipolygons and keeping non-overlapping features intact

I want to merge (multi)polygon geometries any time they overlap partly or fully. For example the Dissolve function in QGIS does not fit my case, since I also want to: Include all parts of the ...
tle's user avatar
  • 103
0 votes
0 answers
38 views

ET_GPBufferPolylines doesn't work

i have a problem with an ET GeoWizard function or maybe just a basic syntax problem. I need to use a script that someome else wrote and which does things that i do not completely understand ...
Nanad's user avatar
  • 1
2 votes
1 answer
93 views

How can I merge polygons in QGIS by attribute only if they are adjacent?

I have a grid with 100 cells classified in deciles of a pollutant concentration. I need to merge polygons from the same decile only if they are adjacent. Someone can help me by pointing me to a ...
Giacomo 's user avatar
5 votes
2 answers
256 views

Making dissolve output as temporary layer using PyQGIS

I want to dissolve my layer by using this script and it is successful, however I want my dissolved layer to be temporary, and my input as any active layer. Can someone help me? from qgis import ...
PyCher's user avatar
  • 171
3 votes
2 answers
113 views

Error using tool dissolve

I am using the Dissolve tool to merge layer. I get the following error (translated from german): "Object (74207) has invalid geometry and was skipped. Please correct the geometry or change the ...
Paulo Matias Montecinos Medel's user avatar
1 vote
1 answer
155 views

Geometry generator - classify objects in QGIS [closed]

How can I display objects classified/dissolved by a specific attribute (f.e. dissolving polygons by state in the attributes), by using the Gemoetry Generator? FID name state 1 Peter BB 2 Ann MV 3 ...
Marek's user avatar
  • 537
2 votes
1 answer
300 views

Google Earth Engine: time series chart of NDVI median value for different land cover classes (ESA/WORLDCOVER/200V)

I'm trying to extract a historical series of ndvi by land cover class (in particular Trees, Shrubland and Grassland), using the ESA collection (ESA/WORLDCOVER/200V) and clipping on my study area (...
Martina Perez's user avatar
1 vote
1 answer
61 views

How to dissolve touching polylines [closed]

I want to dissolve some polylines clipped in a series of polygons, but since there are different polylines in the polygons, I cannot dissolve those with the attributes of polygons. For example in the ...
Reza Naghedi's user avatar
0 votes
1 answer
371 views

GeoPandas - can't write to file because field names are tuples (AttributeError)

I have created a new shapefile by dissolving and computing centroids from an existing shapefile. I have also aggregated values of the existing shapefile to use in the new shapefile. However, when I ...
Maarten 's user avatar
2 votes
0 answers
199 views

Creating single polygon from overlapping ones

I would like to reduce the vertex count of a map by simplifying the overlapping polygons on each layer. The problem is the huge map size, a whole country 1GB .MAP that depicts a whole country with a ...
Felipe La Rotta's user avatar
2 votes
1 answer
1k views

Aggregate (dissolve) polygons leaving internal lines - R

After dissolving polygons, some of the internal lines remain. It seem to be a problem common also to ther softwares (ArcGis and Qgis at least). The dissolve result is this: To dissolve using R, I'm ...
Oalvinegro's user avatar
-2 votes
1 answer
166 views

Count amount of buildings (floating polygons) within neighbourhoods

I want to count the amount of buildings within my neighbourhoods. The dissolve function doesn't work here because the buildings are not intersecting. Does someone have a tip on how I can do this?
Marlot Rijkers's user avatar
1 vote
2 answers
494 views

How to use the dissolve function to create multiple dissolved polygons at once

I had a village level shapefile. I selected villages using the "select by attribute" function to group them into electoral units (labelled as GP in attribute table) I wanted to use the ...
MapnCheese's user avatar
2 votes
1 answer
447 views

How to dissolve two geodataframes, using multiple columns to group by

I want to dissolve a dataframe grouped by two columns. However, in the documentation of the Dissolve function only one column is provided: GeoDataFrame.dissolve(by=None, aggfunc='first', as_index=True,...
soph's user avatar
  • 326
3 votes
1 answer
226 views

Preserving None values in GeoPandas when dissolving (by="id", aggfunc="first", as_index=False)

If I dissolve two geometries with the same id and tell to aggregate the other attributes from the first geometry, I get the attributes values from the second geometry because the first is None. ...
Patrick Baumann's user avatar
2 votes
0 answers
136 views

Seeking PostGIS equivalent of Geopandas dissolve method

Suppose I have a multiline string feature that I have brought into PostgreSQL as a table called nld_table with the following columns: 'SystemID', 'SystemName', 'Location', 'Accred', 'NLD_Access', '...
gwydion93's user avatar
  • 1,903
0 votes
0 answers
571 views

QGIS Calculate Percentage Area of Grid Cell

I'm trying to use QGIS to calculate the area of each grid cell that has been deforested. To do so, I have tried the following: Create Grid to create a 30km x 30km square grid Add Deforestation Layer (...
cstock's user avatar
  • 29
0 votes
0 answers
429 views

Dissolve multiple layers

I want to dissolve over 100 shapefiles into same attributes to eliminate number of features. I was going to merge all the polygon first then dissolve it, but each layer has 10,000 to over 50,000 ...
May0123's user avatar
  • 53
3 votes
1 answer
980 views

Removing partly overlapping lines within the same feature

I have several layers which have features with several parts. These parts are often overlapping however and as a result the Length of the feature is often not correct when I calculate it using $length....
Yelper's user avatar
  • 107
3 votes
2 answers
646 views

Merging/Dissolving multiple layers in QGIS Virtual Layer

I have several polygon layers that I would like to merge and dissolve within a virtual layer in QGIS. So that any changes made to the individual layers will automatically update in the merged/...
Fraxash's user avatar
  • 33
1 vote
1 answer
132 views

Dissolve a intersection along id and keep only features of the bigger area QGIS

In QGIS I'm trying to dissolve an intersection and keep only the features with the bigger area [blue arrow] (compared with other features with same id [red box]). I'm interested in keeping other ...
Jarrid's user avatar
  • 11
1 vote
2 answers
1k views

Combining non-contiguous polygons in ArcGIS Pro

I am trying to combine non-contiguous polygons that are close but not touching one shape. As if you were to draw a line around these five parts connecting them into one. Originally these were part of ...
BHope's user avatar
  • 63
2 votes
1 answer
533 views

How to merge the attributes of point shapefile in QGIS

I am trying to make wind map in QGIS, where I used vector point shapefile. Because I have two different shapefiles I first merged them: Then I Dissolve it where I choose two attributes to dissolved: ...
Kazi's user avatar
  • 151
1 vote
1 answer
119 views

Dissolving features based on another layer in QGIS

I have two layers, see image below: Yellow: the ground where people can build; Red: existing buildings. Create a shapefile of all grounds where >50% of the grounds are free. In order to do this, ...
Maik's user avatar
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