Questions tagged [multipart]

A digital representation of a place or thing that has more than one part but is defined as one feature because it references one set of attributes.

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27
votes
2answers
4k views

Benefits of Multipart Features?

Multipart points, lines, and polygons are implemented in nearly every GIS, but what benefits, if any, do they provide? In a relational database attributes shared by different features can be stored ...
26
votes
2answers
24k views

Understanding difference between Polygon and Multipolygon for shapefiles in QGIS?

Creating Scratch layer gives me a choice between Polygon and Multipolygon, so I started wondering how should I make use of them. Reading a new book "Mastering QGIS" (through this answer by Joseph to ...
13
votes
3answers
40k views

Splitting multi-part polygon into single polygons using ArcGIS Desktop?

How do I split a multipart polygon which consists of several polygons into single polygons so I can delete each polygon without deleting them all at one time? I am using ArcGIS Desktop 10.0.
10
votes
2answers
3k views

What is a multipoint shapefile?

What is the difference between a multipoint shapefile and a point shapefile. in the creation of a shapefile In ArcGIS it has the choice of point shapefile and multipoint shapefile. But I do not know ...
10
votes
3answers
2k views

Create dissolved buffer from multi-geometry (Union by shared attribute and spatial intersection)

I've to create dissolved buffers from multi-point input features. In the example below, the input table contains 4 features. Feature #2 consists of two point geometries. After creating a buffer, I get ...
8
votes
2answers
7k views

Converting huge multipolygon to polygons

I have a shapefile with some huge multipolygons, with 100.000's of parts. What would be the easiest way to split them to singlepart polygons? I'm looking for something like QGIS ”Multipart to ...
8
votes
1answer
9k views

Converting selected multipart features to single parts in QGIS

I'm looking for a way to convert one or many selected multipart feature to different single part features without recreating another layer, the way Arcgis allow a user to select a multipart feature ...
7
votes
1answer
6k views

Converting Polygon to MultiPolygon with Shapely?

I'm writing code that loads data into a database. I have to do some validation/clean up of the data before inserting it. One of the requirements of the database is that this particular table only ...
7
votes
1answer
11k views

Converting Shapely MultiPolygon to Polygon: Technique doesn't always work

In order to get the exterior coordinates I need to convert a shapely MultiPolygon to a Polygon. I do it like this: if poly.geometry.type == 'Polygon': x, y = poly.geometry.exterior.xy elif poly....
7
votes
1answer
2k views

Creating Multi-Part Polygons that touch internally using ArcGIS Desktop?

I have a set of parcels as illustrated in the image below. There are currently no multi-part features in dataset. What I would like to do is to merge (not the right word) all of the parcels with same ...
7
votes
4answers
1k views

Label only the largest polygon of a multi-part polygon layer in QGIS

I am exploring the new Label engine of QGIS 2.12.2 and I found it a great improvement. However, I discover it is not yet up to ArcGIS "standard" when dealing with multipart polygons. As a workaround (...
6
votes
1answer
5k views

“Singleparts to multipart” vs. “Dissolve”

It seems to me that the vector tools "Singleparts to multipart" and "Dissolve" do the same things. Can someone confirm this, please? Or do I overlook something?
6
votes
1answer
3k views

Loading a multipoint shapefile in R

This issue has only been raised in the community once, two years ago, to the best of my knowledge. I think it's high time to raise the issue again! readOGR, from the rgdal package, cannot handle ...
6
votes
1answer
110 views

Bounding box styling of individual parts of multipart objects

In my QGIS project I have a multi-linestring vector layer where each multi-linestring feature consists of small not connected linestrings. I would like to show a bounding box around each of the parts ...
5
votes
1answer
546 views

Creating Multipart Line from coordinate pair lists using Geometry objects in ArcPy?

I am developing a script in which I want to create a multipart line geometry. For example: I have one array of points a,b,c and second array of points e,d,f. I want to create one multipart line ...
5
votes
3answers
2k views

How to determine if a polygon shapefile is multipart or singlepart?

The ArcMap Properties dialog does not indicate if a shapefile contains multipart or singlepart polygons. Is there some other way to identify if a polygonal shapefile (or any feature class, for that ...
5
votes
1answer
204 views

Is there a “Merge Parts” tool in QGIS?

In the advanced digitizing toolbar, QGIS has these 3 tools: Split Features, Split Parts, and Merge Features. Is there a tool or equivalent algorithm for the logical fourth one: "Merge Parts"? This ...
5
votes
1answer
472 views

Changing order of parts in multipart geometry using ArcGIS for Desktop (or ArcPy)?

Is it possible in ArcGIS to change order of the parts in multipart geometry? In the context menu i founded "insert before" , "insert after" but it never comes active ... or is it possible via python?...
4
votes
2answers
503 views

How to place only one symbol on the centroid of a multipart polygon?

I am using QGIS version 2.14.1 (Essen). I would like to place symbols on the centroids of my data. The problem is that some of my data has multi-part polygons, which means it places the symbol at the ...
4
votes
1answer
2k views

Cut part of a shapefile

This is my first time with QGIS and maybe it is an easy question but I can't figure out how to cut part of a layer to add it to another one. In the image you can find (red circles) parts of a layer ...
4
votes
1answer
102 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 ...
4
votes
2answers
432 views

How to extract nodes with PostGIS to a multipoint geometry

I have a line in a PostGIS table test_line. I want to extract it's nodes into a multipoint geometry. I tried the following: SELECT ST_Collect((ST_DumpPoints(the_geom)).geom) FROM test_line; But it ...
4
votes
1answer
255 views

Export multipolygons into a GeoPackage

In FME, I use the Aggregator to merge polygons based on one attribute (desnat in my example file). When the output is Shapefile, multipolygons are created and all works fine. When the output is OGC ...
4
votes
2answers
174 views

Bug of QGIS when using “multipart to singlepart”?

I used yesterday, in QGIS 3.2.3 the tool to convert multiline to a single line ("multipart to single part"). I chose the option of the command "multipart to single part" the geometry feature (line) ...
4
votes
1answer
342 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 ...
4
votes
1answer
232 views

Problems updating geometry of multipart and donut polygons with Arcpy

I am trying to update the geometry of some features (polygons) to allow stretching / shrinking in the X and Y planes, but am struggling to get this to work for multipart polygons and for those with an ...
3
votes
2answers
1k views

Converting adjacent singlepart polygons to multipart? [duplicate]

I am interested in converting a polygon featureclass created via Create Fishnet (Data Management) from singleparts to multipart. QGIS has a very handy tool called singleparts to multipart that does ...
3
votes
1answer
211 views

Float not iterable

import arcpy arcpy.env.workspace = "c:/esripress/python/data" fc = "Hawaii.shp"     cursor = arcpy.da.SearchCursor(fc, ["OID@","SHAPE@"])   for shape in cursor:        print "Total area: {}"....
3
votes
2answers
3k views

Merge single points to multi point geometry

Is it possible to transform a point shapefile in single part geometry to a shapefile with multi-point geometry based on an attribute. e.g. in the file are 50.000 records in 700 categories, now I want ...
3
votes
1answer
290 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 ...
3
votes
1answer
834 views

Is there a way to create multipart from singlepart features based on selected features only?

QGIS has a tool for creating multipart features in the Geometry Tools section. However, this is applied to a whole layer, which leads to the yellow selection in the image below when used (selecting ...
3
votes
1answer
2k views

Discover multipart features in a layer in QGIS

I am trying to identify multipart features using QGIS version is 1.8.0. I've tried: look at the attributes table select a random feature and check in the canvas if there are multiple geometries ...
3
votes
1answer
166 views

Dissolve singlepart features into multipart based on another polygon?

I'm working on generating a water feature layer that eliminates a lot of the swamp/marsh areas in my county. Using raster analysis (iso unsupervised cluster, majority filter, boundary clean, etc) and ...
2
votes
1answer
921 views

ArcPy getPartCount always returns 1 on multipart polygons?

in this post Why does the method partCount in ArcGIS always give back a value of 1? a problem occured that could easily be reproduced. partCount is always 1! Is it a wrong usage of partCount or did ...
2
votes
1answer
5k views

Converting multipoint geometry to ONE single point using ArcGIS Desktop?

I have an ArcGIS file geodatabase with two featureClasses. One is a point featureClass which represents the centroids of the cells of a regular grid. The second represents the corners of each grid ...
2
votes
1answer
723 views

How to merge single polygons to multi part polygons by maximum distances?

I have a polygon layer with a land-use class and ID for every polygon. How can I merge polygons (into multi part polygon) which do not adjoin, but are not further than x meters apart from each other. ...
2
votes
1answer
322 views

How to select multi-part polygons from a layer using PyQGIS

My script is - # Find all multipart features in the active layer l = iface.activeLayer() iter = l.getFeatures() geoms = [] for feature in iter:     geom = feature.geometry()     if geom.isMultipart()...
2
votes
2answers
353 views

Does exist a Python library to generate polygons avoiding antimeridian issues?

If I need to generate a polygon that crosses the anti-meridian, does it exists a Python library that treat such cases (partitioning such polygon and generate a multipart polygon)?
2
votes
1answer
1k views

How to divide a multipart polygon into many polygons using QGIS?

I have a polygon which is actually composed of many polygons but it results as unique geometry in the shapefile. It's easier to explain with a picture. The yellow parts are in my shapefile a single ...
2
votes
2answers
1k views

Selecting MultiPart Polygons if there are buildings in at least two of the parts

my data situation: shape of polygons (some are MultiPart Poylgons) shape of building locations (Points) What I need: Select all polygons that have two ore more parts and contain one building or more ...
2
votes
1answer
405 views

ST_LineMerge doesn't return LineString

I want to create a LINESTRING from a MULTILINESTRING. However in the following case ST_MultiLineString is returned: Select ST_GeometryType(ST_LineMerge(ST_AsText(' MULTILINESTRING( (-70.52570888 -33....
2
votes
2answers
92 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. ...
2
votes
1answer
540 views

Does the GDAL GeoJSON driver read or write multipart geometries?

In the documentation for the GDAL GeoJSON driver, I can only see mention of primitive geometries. Does the GDAL GeoJSON driver read multipart geometries like MultiLineString? If not, is there ...
2
votes
1answer
107 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 ...
2
votes
1answer
119 views

Dissolving features to only have multiparts when they are within 100 feet of one another

I want to have a selection of parcels that is dissolved by land owner and within 3 miles of a polyline. If the same owner owns parcels on opposite sides of a road (within 100 feet or so), I want the ...
2
votes
0answers
21 views

How to delete a file after processing an algorithm in QGIS 2.18?

I am trying to delete an intermediate file ("Temp_merged.shp") after running the singleparts to multiparts algorithm in QGIS 2.18. import glob, os, processing path_to_shp = "C:/Temp/Tracks/" ...
2
votes
0answers
32 views

Error creating new polygons. QGIS

When I work in QGIS and try to fill gaps between polygons creating another one over them (project snapping settings are selected as Avoid intersection), I hope "fill" this gap with just one polygon ...
2
votes
0answers
251 views

How to find a polygon error in QGIS?

I loaded the following multipart polygon in QGIS which consists of three separate polygons. The highlighted (yellow) polygon consists of the bigger upper part and the smaller lower part. My aim is to ...
2
votes
0answers
33 views

numbering of features when dissolving non-contiguous polygons

I have dissolved polygons together to make feature A. Some of the polygons are contiguous and some are not. Therefore, there is a unique row for each feature (singlepart to multipart). In ArcGIS or ...
2
votes
0answers
120 views

Removing overlap within multipart polygon in ArcGIS for Desktop?

ArcMap 10.1 SP 1 License: Advanced I am attempting to remove overlapping portions of a multipart without going through the steps exporting or creating a layer from each part and clipping individually....