Geographic Information Systems

Questions tagged [dissolve]

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To merge features based on specified attributes.

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29 views

Quicker function than dissolve and difference

I'm on QGIS (v. 3.6) trying to create a map of Florida's hydrography using the NHD "Water Areas" shapefile. Methodology is to fix any invalid geometries in the NHD data, dissolve the layer, and then ...
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49 views

Improving speed of GeoPandas dissolve?

I am trying to dissolve grid spaces by category using GeoPandas' dissolve function, but it doesn't finish after hours of running and I want to make sure I'm not doing something wrong and/or there isn'...
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23 views

QGIS 2.18.28 Dissolve Error: “-2147483645 See log for more details”

I am doing property research on a county in Texas. I have all the parcel data and am trying to dissolve by Owner Name so that I can use the info tool to quickly see all the properties a given person ...
2
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1answer
36 views

Erasing boundaries between polygons that are next to each other using QGIS?

I have files that representes individual houses and blocks. I want to have a file that represents a residential area in a block. Is there a way to erase the line, boundaries, between polygons that ...
2
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1answer
40 views

QGIS (merging, dissolve, union) lines of same name

I have street data where roads are segmented for no particular reason. I want to merge, dissolve or union whatever seems fit to make a single flat line. I H have tried above processes in QGIS but ...
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15 views

ArcMap Model with parameters

How do I get the fields from the intersect results in my arcmap model to appear as the possible 'statistics fields' for my dissolve tool when using model parameters? I have the statstics field set up ...
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28 views

Unary union/Dissolve returns null geometry in QGIS 3

I am writing a python processing script in QGIS 3. In it, I have polygon geometry objects stored in a list polygonGeoms and I want to dissolve all of it into one geometry. However, when calling the ...
2
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1answer
110 views

How to dissolve shared line segments together in QGIS?

I have 2 features which are lines on a single layer re-projected to ESPG:2039. I wish to combine them into one MultiLineString but in a way that their common part is merged to a single LineString. I'...
2
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1answer
34 views

Counting the number of shared point within polygons [closed]

I have a set of points on a map, each with a unique location id, with one or more points within a number of polygons with unique polygon ids. I am trying to associate each location id with the number ...
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0answers
53 views

Dissolve Line Strings to one string - “No Shapely geometry can be created from null value”

I have a layer with 7000 LineStrings, all represent bus routes: It seems that all the bus routes are contiguous, but I'm not sure of it. I'm trying to use python shapely to dissolve all those ...
2
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2answers
51 views

Dissolve with common value in a field and not common in another

I have a shapefile in QGIS and I want to dissolve it with the options: A field named 'specialid' has the same value A field named 'city' has different value Ok the first is very easy. It is ...
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1answer
55 views

Dissolve (merge) polygons QGIS based on attribute values only when are adjacent

I am a fairly new user of QGIS having a question regarding dissolve functionality. I am working with the NUTS-2 shapefiles provided by EU, which I have imported in QGIS. I have created a new layer ...
2
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1answer
68 views

Dissolve (merge) polygons QGIS based on (non exact) attribute values

I am a fairly new user of QGIS having a question regarding dissolve functionality. I am working with the NUTS-2 shapefiles provided by EU, which I have imported in QGIS. To ease the discussion, I ...
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33 views

QGIS dissolves all different shapes into one feature instead of multiple features [duplicate]

I'm pretty new to QGIS and geoprocessing. I have a layer of points representing traffic lights - where each point is a different feature: I wish to create a layer with traffic light junctions based ...
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33 views

Retrieve attribute with max value by group

I have a intersected counties shapefile with wind potential category attribute. What I want to do is to dissolve the features grouping them by county, and retrieve the WPC value which has the largest ...
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0answers
36 views

Dissolve polygons using clustering

The attached vector file contains thousands of individual polygons (a byproduct of the underlying raster image). The result of using polygonize function in qgis. My intent is to dissolve the polygons ...
2
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1answer
80 views

Dissolve Field Not Showing in QGIS?

Using QGIS 3.6 Currently trying to dissolve a polygon layer by FIELD values. QGIS 3.6 and the fields won't show up. In fact I am unable to dissolve by FIELD for any layer in my entire project. If I ...
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18 views

Dissolve on attribute field and location?

I've got a county parcel shapefile and I'm wanting to find all the properties over 300 acres. When I dissolve based on ownership and search for dissolved properties that sum over 300 acres, some of ...
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1answer
157 views

Dissolving polygons to single part features with Python (shapely and fiona)?

I used the code from Dissolving polygons based on multiple attributes with Python (shapely and fiona)? to dissolve a shapefile using shapely and fiona. However the output creates multi-part geometries....
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1answer
33 views

Filter options are not saving in Dissolve algorithm window through Graphical modeler in QGIS 2

I am working on my project in QGIS 2.18 through Graphical modeller and using some basic algorithms for polyline objects. However, I do not understand why specification for Dissolve algorithm cannot ...
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79 views

How to remove artifacts with SQL Server GEOMETRTY::UnionAggregate()

We'd like to do an effective "real-time dissolve" on an Esri feature class with a SQL GEOMETRY shape where a parcel layer is "dissolved" into products using an attribute (ProductID) of the parcel ...
4
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1answer
91 views

Using Dissolve and Multipart to Singlepart in QGIS?

I started with a network of polylines. In QGIS I used dissolve to 'merge' all lines according to an attribute value. This did exactly that, but included non-connecting lines which I don't want. I ...
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1answer
111 views

Merge connected lines and split them after set unequal distances

I need to edit line features in QGIS 3.4.4. I have more than 1000 line features that I want to first merge and then split. The line features describe roads in useless intervals, my goal is to ...
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27 views

Dissolving GeoJSON with nodes and lines to one average line?

I have a GeoJSON with two layers. One with lines and one with nodes. I'd like to dissolve it (or at least the layer with the nodes) to one single line, by averaging the positions. I've looked at Turf....
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1answer
154 views

Dissolving featurecollection in google earth engine?

Here is the link to my GEE code: https://code.earthengine.google.com/99b494aacf00df398e0e710ec02c13e8 Here is the code (DMDP is an asset and to see it please follow the link): Map.centerObject(...
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1answer
51 views

Mapping Commuting Zones from Counties for US 1990 Data in ArcMap?

This question follows Seeking 1990 US Commuting Zone shapefiles? I am attempting to map US commuting zones as defined in 1990. I have successfully mapped counties from a county shapefile obtained ...
2
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1answer
76 views

QGIS: Dissolve after raster-to-polygon not working correctly, only dissolving a portion of the vector layer

I am working with QGIS and am trying to convert a raster layer into a vector layer. I have converted it to a polygon from raster (image below), and then wish to dissolve this polygon into a single ...
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2answers
36 views

Dissolve everything except for one particular polygon

I want to dissolve these polygons (column FIRST_N03_003) except for FID 34 and 77. Essentially, the 003 column is the state, and the 004 column is the city, but some cities are independent and do not ...
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0answers
140 views

QGIS: Dissolving Polygons with Self-Intersection

I have created multiple polygons with some subset of track-lines, with the order of time those points were recorded. Therefore some of the polygons have self-intersection within the polygon. Is there ...
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0answers
53 views

Promoting to multipart using PyQGIS?

I am creating a code that aggregates neighbouring polygons if they have similar value on the field 'DN' and if they are closer than 50 m.Then I want to iterate this 3 times. I could already get the ...
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1answer
268 views

Dissolving using PyQGIS?

I have trouble to use function dissolve to dissolve polygons by field value in PyQGIS3. In PyQGIS2 this line was doing the job: QgsGeometryAnalyzer().dissolve(ki, "name.shp", onlySelectedFeatures=...
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1answer
86 views

Dissolve lines putting segments out of order QGIS

I'm using a polyline river layer in QGIS to calculate river miles, but am ending up with points out of order. Starting with a river layer that is broken into reaches (short sections), I'm dissolving ...
2
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0answers
154 views

Is PostGIS faster than Shapely [closed]

I've recently tried using Shapely to dissolve and intersect large sets of 100'000+ geometries, some of them quite complex. This would take me at least one hour, at which point I would usually shut the ...
3
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3answers
73 views

Dissolving polygons when only relationship is spatial location?

I have a feature class with parcel information; some of the parcels have roads included while others do not. When a parcel has a road included there is always a matching parcel without the road ...
2
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0answers
275 views

Dissolving large sets of polygons [closed]

We have many datasets, each containing about 150'000 polygons. We would like to dissolve each dataset down to about 2500 polygons, based on a given attribute. We've successfully done this using the ...
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1answer
42 views

Buffer all polygon feature classes inside geodatabase using ArcGIS 10.4

I have a geodatabase which contain a hundred of separated polygon feature classes. I want to create a same value buffer of all feature classes in same time. Each buffer must have a "dissolve" option. ...
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1answer
95 views

Merge many objects with equal position while sum up their attribute values in QGIS

I´m looking for a smart way to merge multiple line objects with the same geometry and same position in one layer while also sum up their attribute values. The result should be only one geometry (...
1
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1answer
60 views

Dissolve polygons based on number of polygons

How can I dissolve group of polygons into many polygons based on specific number? For example I have 100 points which are beside each other I need to dissolve each nearest 5 polygons into 1.
2
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1answer
257 views

Dissolve using attribute field and area

How can I dissolve a shapefile with polygons and keep the information of the polygons that have the bigger area in QGIS? example: two polygons with the same field values but one of them is bigger ...
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0answers
40 views

Summarize table by group and add logic to keep data

I need to dissolve a polygon layer by group but, at the same time, I need to keep some of the data in extra columns. This is the diagram: This is the logic for the new group: Cod = "Cod" where N1 ...
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0answers
258 views

Dissolve with stats plugin does not appear in QGIS 3.0

So far we have tried to: find it in the plugin repository from QGIS, with no luck. install the plugin downloading it from the web QGIS Python Plugins Repository: https://plugins.qgis.org/plugins/...
2
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1answer
98 views

Dissolving polygons on distance condition using PostGIS?

I'm tying to group some polygons in same layer, on geometry & attribute conditions: within 0.8m from each other and with same value in a column. With answers I've found here I've got something ...
1
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1answer
33 views

Using Dissolve Tool in ArcGIS Desktop?

I am using ArcGIS Desktop 10.4.1 and trying to create a mailing list using parcel data. I need the parcel lines to be dissolved if they have the same owner name and are adjacent or adjoining. ...
2
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1answer
293 views

Dissolve not based on attribute in geopandas

I would like to dissolve a shapefile regardless of attribute content using geopandas. The regular dissolve can be accomplished with something like this: import geopandas all = geopandas.read_file(...
2
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2answers
558 views

QGIS. Dissolve polygons to create new layer with stats. Not working

I'm using QGIS 3.2.1 (Bonn) I'm trying to dissolve and create statistics from a group of polygons, but QGIS is not making it. I do not know if I'm missing something or the software has a bug. These ...
2
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1answer
79 views

Dissolving feature/field by interval using ArcGIS Desktop?

I have a huge dataset with flowpaths containing a catchment area for each line. The attribute table has ~ 780.000 rows, and thereby 780.000 features in the mapwindow. Is it possible by using a field ...
6
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0answers
190 views

How do I select the longest connected lines from PostGIS ST_ApproximateMedialAxis?

I used PostGIS ST_ApproximateMedialAxis to transform polygons representing mountain ranges into a series of lines. Now, I'd like to select only the "longest" line segment for each group, so that I ...
2
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2answers
297 views

How to polygonise a large and detailed raster into a single valid polygon with QGIS?

I am doing research on the protected areas of the Amazon rainforest and I need to create a single polygon layer that has all the forested non-protected areas in one attribute row. I have tried using ...
2
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1answer
45 views

Merge/Dissolve Polygon overlapping within

I have a polygon that has been broken down to an intersecting analysis point. Each segment has its own acreage within an acre field on the attribute table. I want the intersecting lines to be removed ...
4
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1answer
156 views

QChainage doesn't place points evenly along dissolved lines

I am trying to add mile markers to interstate centerline data. I've tried both the native dissolve tool (which freezes QGis) and SAGA line dissolve to create one continuous line. When I run the ...

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