Questions tagged [dissolve]
To merge features based on specified attributes.
539
questions
3
votes
1
answer
63
views
Dissolving polygons within other polygons and accumulated one of their values in QGIS
I am planning a district heating system (pipe system in red). For this I need the total heat consumption of all cadastral units (in blue) next to the pipe to calculate the dimension. There are zero to ...
- 717
0
votes
1
answer
42
views
Combine dissolve aggfunc and lambda function
I am looking to aggregate different polygons and applies analytical functions at the same time.
I have tried:
df.dissolve(by=['ville','arrondissement','quartier'],
aggfunc={'transaction':'count','...
- 485
1
vote
0
answers
59
views
QGIS Native Dissolve only merges polygons vertically
I have a raster which I'm trying to convert into polygons. I have managed to convert them into polygons as seen below. All these polygons only have a value of 1 attached to them.
Now I want to merge ...
- 123
1
vote
1
answer
33
views
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?...
- 11
3
votes
1
answer
94
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 ...
- 717
2
votes
0
answers
69
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 ...
- 343
0
votes
0
answers
18
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 ...
3
votes
1
answer
379
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 ...
- 343
0
votes
0
answers
29
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 ...
1
vote
2
answers
100
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 ...
- 31
0
votes
0
answers
121
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, ...
- 249
1
vote
0
answers
45
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). ...
- 330
1
vote
2
answers
196
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 ...
- 249
0
votes
0
answers
23
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.
- 475
1
vote
0
answers
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.
- 475
0
votes
1
answer
67
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 ...
- 31
3
votes
1
answer
3k
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 "...
- 45
0
votes
0
answers
27
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 ...
- 43
0
votes
1
answer
252
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
"...
- 355
1
vote
1
answer
153
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 ...
- 1,297
2
votes
0
answers
28
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 ...
- 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 ...
- 1
0
votes
1
answer
438
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 ...
6
votes
1
answer
161
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 "...
- 93
3
votes
1
answer
1k
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. ...
- 44.2k
1
vote
1
answer
751
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 ...
- 51
1
vote
0
answers
390
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).
...
- 11
5
votes
1
answer
322
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 ...
- 1,143
2
votes
1
answer
201
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 ...
- 21
2
votes
1
answer
568
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 ...
- 103
0
votes
0
answers
41
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 ...
- 1
2
votes
1
answer
96
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 ...
- 21
5
votes
2
answers
284
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 ...
- 171
3
votes
2
answers
130
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 ...
1
vote
1
answer
172
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
...
- 537
2
votes
1
answer
326
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 (...
1
vote
1
answer
62
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 ...
- 11
0
votes
1
answer
413
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 ...
- 307
2
votes
0
answers
210
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 ...
- 123
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 ...
- 203
-2
votes
1
answer
200
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?
- 103
1
vote
2
answers
579
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 ...
- 41
2
votes
1
answer
522
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,...
- 330
3
votes
1
answer
241
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.
...
2
votes
0
answers
137
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', '...
- 1,933
0
votes
0
answers
626
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 (...
- 29
0
votes
0
answers
491
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 ...
- 53
3
votes
1
answer
1k
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....
- 107
4
votes
2
answers
754
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/...
- 43
1
vote
1
answer
136
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 ...
- 11