To merge features based on specified attributes.

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3
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0answers
47 views

Issue with dissolving a polygons layer in QGIS 2.4

I downloaded a dataset of roads and parks from OSM. I then buffered the roads and merged with the parks. Now - all i want is to dissolve / union all the features in the merged layer. I fail to do it ...
2
votes
1answer
60 views

QGIS 2.4 dissolve doesnt work properly, why?

I am used to work with ArcGIS and now I started to explore QGIS more. I have problem with dissolve function. I have administrative borders and I would like to dissolve them into higher administrative ...
2
votes
0answers
16 views

ArcGIS dissolve analysis output issues in geoserver wfs/ PostGIS

I have an ArcGIS dissolve analysis output (parcel data) that needs to be loaded on PostGIS and published as a wfs from geoserver. The issue is that the ArcGIS dissolve output shapefile, although can ...
1
vote
0answers
69 views

Is table with 20,000 rows and 5 columns too large for Dissolve of ArcGIS for Desktop?

Is a table with 20 000 rows and 5 columns too large for arc map 10.2.1? I have tried several things without success to dissolve this table based on one feature. The table was obtained from the ...
3
votes
1answer
65 views

QGIS 2.4.0: dissolve tool renders artifacts / errors

The dissolve tool (vector>geoprocessing tools>dissolve) renders some artifacts on shapes with high number of polygons. I’m using a shapefile with 3222 polygons and I’m trying to dissolve it using the ...
1
vote
2answers
57 views

Dissolve tool misses out two polygons

I'm trying to dissolve polygons based on a code number in the attribute table. It all works well, with an exception of two polygons that fail to dissolve - they literally drop out from the output. It ...
1
vote
1answer
22 views

Unsplitting Zpolylines without flattening vertical line segments?

Trying to figure out how to fully keep vertical line segments when using Dissolve/unspit lines... The first image shows the original Zlines in Arcscene The second image is the result of a Dissolve ...
3
votes
4answers
162 views

How to fix quickly a lot of geometry validity errors in QGIS?

I am working on ownership data at a US county level. I have one shapefile per county that contains thousands of tax parcels. I need to dissolve the polygons representing parcels owned by the same ...
0
votes
0answers
48 views

Statistics field in the dissolve tool not always accurate

When I run the Dissolve Tool using a Statistics Field (SUM being the statistic type) and proceed to check the SUM values for accuracy by comparing against the data in the original feature class, I ...
8
votes
2answers
309 views

Does dissolving features improve geoprocessing efficiency?

I have a large set of line data (>140,000 features). Is there a processing advantage, in either time required or (more importantly) memory used: to running Dissolve on the data before running ...
1
vote
1answer
38 views

Merge polygon based on other line shape file PostGIS

I have a polygon shape file and a line shape file. I would like to merge two polygons which shares the same border along with line shape. Finally the line should be removed in polygon shape file. In ...
1
vote
1answer
54 views

Postgres/PostGIS: Dissolve multiple fields with COUNT (Point shape)

I have loaded point .shp feature classes into Postgres 9.3 db, and enabled postgis,plpgsql,postgis_topology extensions. I'm looking to dissolve multiple fields within a single table 'TABLE1' and add ...
3
votes
2answers
58 views

problem merging polygons based on a column value - using Spatialite

edit: as I am unfamiliar with any tools I decided to try my luck with PostGis. I imported my data. and executed the query : create merged as select delomrade_code, st_union(geometry) from grunnkrets ...
1
vote
0answers
23 views

Polygon dissolve in DB

I have a polygon feature class with more than 100,000 polygons in DB2 table. I would like to dissolve them based on a single field to reduce the row numbers. Is there any commands / SQL in DB2 to ...
4
votes
5answers
365 views

Dissolving polygons fails on computers with small amount of RAM

When I'm trying to dissolve a polygon through an arcpy script the operation fails with the 999999 error on computers with small amount of RAM [~3 GB] (known issue). Unfortunately neither this, that ...
2
votes
1answer
28 views

ArcGIS Dissolve leaving feature snippets in dissolved polyons. Repair doesn't fix

I'm trying to dissolve some low-level polygons, but the result I'm getting has lots of little pieces of lines left floating around in the output polygons. I've tried doing "repair geometry" on both ...
2
votes
0answers
44 views

how to make a list of features constructing the dissolved feature?

I need to simplify my road network using the dissolve function to remove nodes not occurring on the intersections. the following code is doing that. arcpy.Dissolve_management(self.address_cor_layer2, ...
0
votes
1answer
124 views

How to dissolve naturalearth vectordata with gdal?

trying to use the workflow described by @aflaciano at How to render area that crosses 180°? I did the following: 1) downloaded and installed gdal-111-1600-x64-core.msi from ...
1
vote
1answer
69 views

How to dissolve adjacent parcels by same owner but include those parcels located across the street with the same owner?

In trying to determine the total contiguous stream length per landowner, I dissolved parcels by parcel owner name attribute and intersected these dissolved parcels with streams. However, dissolving ...
0
votes
0answers
84 views

Need advice on converting large geodatabase into shapefile or postgis

tl;dr: I have a fgdb w/ 800k tiny polygons representing high risk flood areas. I need to sum the area of these polygons within each administrative boundary (HUCs) and have a ratio per huc of high risk ...
1
vote
2answers
119 views

Merge Error: Not Enough Memory

I'm attempting to make a flood plain map for a school project, and am using FEMA Flood Hazard Symbology for the legend. I've dissolved by a Flood Zone Field, but am left with two attributes both named ...
1
vote
3answers
193 views

Why would Dissolve stop working in ArcGIS for Desktop?

I have an ArcMap Add-In that completes various geoprocessing steps, including Dissolve (using ESRI.ArcGIS.DataManagementTools.Dissolve). This tool worked at 10.0, but I just upgraded to 10.1 SP1 and ...
2
votes
2answers
607 views

Problem with merging and dissolving a shapefile in R

I am migrating from ArcMAP to opensource GIS. I've succesfully installed R and many packages in a Ubuntu 12.04 machine. I am used to linux and programming in C, but not to R and its syntax. I am ...
0
votes
1answer
95 views

QgsGeometryAnalyzer.dissolve problems

I am completely new to the QGIS python api and I am running into an error which I cannot solve when trying to use the dissolve class. I used the basics of the PyQGIS Cookbook. In my understanding ...
1
vote
1answer
175 views

Dissolve large dataset in ArcGIS and QGIS

I have more than 80k point data. I have created few buffer from 1 to 5 km of them. Now I want to get the covered area by 1 km to 5 km buffered range. For this I have tried to dissolve those individual ...
2
votes
1answer
47 views

How to dissolve geodatabase map across two subdivision levels in Arcgis 10.2

The existing polygon database contains attribute table with the following structure, and has three levels; country, state, and city (and many other countries not listed below). I want to dissolve the ...
2
votes
2answers
108 views

arcpy.Dissolve fails; need a arcpy dissolve to multipart workaround

I have a arcpy script in which I am using arcpy.Dissolve on a single feature class with multiple features to get a single multi-part feature in the output. The script is successful only part of the ...
1
vote
0answers
60 views

How to calculate Median of a table field in the Dissolve Tool of ArcGIS?

The Dissolve Tool of ArcGIS 10.0 has some statistical parameters as a type of calculation new values of each field in a process of dissolving of identical parameters . It has SUM, MAX, MIN, RANGE, ...
0
votes
1answer
63 views

Splitting hexagonal grid into segments, dissolve by location

I am a little bit frustrated because I want to do something I did 5 years ago and I can't figure out how to do it again. I am creating a turnover map of species communities using R and ArcGIS 9.3. As ...
1
vote
2answers
581 views

How to combine rows in an attribute table

I'm fairly new to GIS and could use some help with an issue I've run across. I have an attribute table with three columns "FID" "Shape" and "Class" All records have the same shape (polygon). Each ...
0
votes
0answers
47 views

How to get the boundaries of a polygon by property

I have the cartography of my city (Santiago) and i need to obtain the nodes that conform the hull (not necessarily convex) of different districts, the boundaries. Each node has the same "DIS"( ...
1
vote
1answer
142 views

python dissolve by field error

I would like to dissolve a feature class by a field. When I run the code, I receive an error that says, "invalid topology [out of memory]" I have 16GB of RAM and terabytes available on the hard drive. ...
1
vote
1answer
78 views

MSSQL server 2008 dissolve sql query

I have a set of spatial objects in a MSSQL server 2008 R2 trying to dissolve adjoining objects where one of the attributes are equal. The table below is somewhat representative to my original table: ...
0
votes
0answers
76 views

Dissolve a Geometric Network in ArcGIS

I have a geometric network of water mains in ArcGIS. It it composed of a line feature class. I would like to dissolve it based on whether line segments share common endpoints only. So basically ...
1
vote
2answers
176 views

Looking for dissolve algorithm for Javascript

I have three adjacent polygons that together make up a larger shape. I need an algorithm that will dissolve the internal borders leaving only the outside border. An example would be a group of ...
1
vote
1answer
121 views

Aggregate/dissolve MySQL geometry

On Centos, I have a MySQL 5 database with a MyISAM table that has a geometry column with a spatial index, containing US county boundaries. Trying to combine/aggregate/dissolve some of these into as ...
1
vote
0answers
26 views

How do I dissolve to a predetermined number of contiguous geographies based on equal division of a value?

Let's say I have a layer that is the state of Oklahoma, broken up by county, and I want to dissolve it into contiguous regions of roughly equal population size, and I want to define how many regions ...
2
votes
2answers
205 views

Why is my dissolve not outputting my features correctly?

I have a parcel polygon layer consisting of ~30,000 polygons that can have one of three values for city limits: 0, 1, and null. I execute a dissolve on this layer with "Create Multipart Features" ...
0
votes
2answers
113 views

Low resolution raster conversions to vector yielding millions of single pixel polygons. Trying to merge all directly adjacent polygons

I'm trying to scan plain pdf maps containing color-coded geographic regions and convert them into undifferentiated (I don't actually need them to contain any attribute data) overlays. My workflow is ...
2
votes
1answer
202 views

How to define polygons overlapping each other?

I have a shapefile of landuse in different catchments. I want to calculate the percentage of each landuse category in each catchment using Tabulate Intersection. Before using this tool, I had ...
0
votes
1answer
63 views

Dissolving polygons closers than 50m into a single shape QGIS

I’m new with GIS (coming from a CAD background) and using QGIS 2.0.1. I have a very detailed map of urban fabric in a UK region, to the detail of individual buildings. I want to simplify that map by ...
2
votes
1answer
456 views

Merging polylines together keeping the attributes of the largest one

I have a set of polygons with polylines running through them. I am trying to assign the polylines the polygon ID that they pass through the most. I have already split the polylines to the polygon ...
5
votes
2answers
119 views

Select 90% matching attributes

I have a shapefile (.shp) of 180k roads with information of street name. I need to do a Dissolve on that road network to make only one feature per name. But I have a problem by doing that task ...
2
votes
0answers
58 views

Dissolve Statistics Fields and Statistic Type as Parameters in GeoProcessor

I have a published service which uses a dissolve. In arcMap the I get prompted for all the fields, including statistics fields and stat type. I have the statistics fields marked as parameters. ...
2
votes
1answer
339 views

Dissolve features in ArcGIS using multiple attributes

This may sound simple, apologies if I missed some earlier discussion on same subject. I have a big set of road data with road numbers and also zone numbers . The road names can repeat across the ...
1
vote
2answers
4k views

How to Merge/Dissolve Polygons By Common Attribute Field in QGIS?

I have joined corresponding Local Enterprise Partnerships table data into a polygon shape file containing UK Local Authorities. How do I Dissolve or Merge the the Local Authorities polygons by ...
0
votes
0answers
50 views

Dissolving overlapping polygons - issue in QGIS [duplicate]

I have the OS Code-Point map which I want to dissolve into the regions that my company use. I have used the dissolve function in QGIS, but it is having a problem where a vertical street overlaps with ...
0
votes
2answers
192 views

How can I get a single part dissolve using ST_Union or ST_Aggr_Union?

I am trying to get dissolve functionality using ST_Union using this query : SELECT c.fid, ST_Union(c.boundaryshape) FROM c GROUP BY c.fid; Than I found instead of using ST_Union I should use ...
5
votes
1answer
211 views

How to achieve equivalent to Dissolve from ArcGIS for Desktop using ST_Union?

I am trying to achieve an equivalent to the Dissolve tool from ArcGIS for Desktop using ST_Union from PostGIS but it seems I am not getting expected result. I have one table which has certain ...
1
vote
3answers
453 views

Is there a dissolve / ST_Union function that will close gaps between features?

I've been reading a number of related threads about ST_Union, ST_SnapToGrid and ST_Dump but I haven't been able to solve my problem. The problem is I am trying to merge Tiger/line census tracts that ...