Questions tagged [grouping]
Associating or clustering data based on common attributes or properties.
148
questions
3
votes
2
answers
147
views
Classifying in QGIS into arbitrary number of percentiles instead of quantiles, based on attribute field value
Extending this question and this one: In QGIS, there are special expression functions for the first and third quartile (q1 and q3) and as well as median (median). So it's easily possible to categorise ...
- 67.2k
0
votes
1
answer
77
views
PostgreSQL and extension tablefunc with enumerated type
In PostgreSQL,
I created an enumerated type
CREATE TYPE w_sebio.t_sebio_type_sad
as ENUM ('transféré', 'traité', 'non soumis', 'ouvert', 'non traité','PAC réalisé');
then a table
CREATE TABLE w_sebio....
- 899
3
votes
1
answer
65
views
What is the equivalent of native:aggregate() in QGIS Field Calculator?
I have two layers which I want to connect using the aggregate() function with the Field Calculator. I can do this using the processing tool:
processing.run("native:aggregate", {
'INPUT' :...
- 389
0
votes
1
answer
55
views
Count number of records with the same date
I have a table with species sightings and I would like to add a field with the sighting number in that day (every day should start again from number 1). Ideally this should be done automatically as I ...
- 33
1
vote
0
answers
12
views
Extract subgroups w/ max time difference between points < 2.5h in QGIS
I have several point layers can be grouped by "date" and "new_id", such as:
datetime_lcl date new_id
05/06/2023 09:30:01 05/06/2023 1
05/06/2023 10:...
1
vote
0
answers
41
views
Grouping points within counties and symbolizing their data as pie charts in QGIS
I need to combine/categorize points within different polygons while retaining some of their values. I've made up a scenario to try and simplify my problem.
The layers I have to work with are a point ...
- 19
1
vote
1
answer
62
views
Cannot enable 'Any organization's members' setting when creating Group or updating properties using ArcGIS Python API [closed]
I am creating a group using the ArcGIS for Python API, there is limited information in the API Reference here.
And I found some more information in the Rest Reference relating to the membershipAccess ...
- 1,635
1
vote
1
answer
32
views
What do parameters provider_group_name and provider achieve in GroupManager create function when using ArcGIS Python API?
The create() function in the GroupManager module has two parameters; provide_group_name and provider.
See API Reference
What is the purpose of these parameters?
I cannot find any documentation ...
- 1,635
5
votes
2
answers
237
views
Calculating mean with group by based on another column in QGIS Field Calculator
I have daily temperature data for several cities from January to December.
I'd like to calculate the average temperature per month for each city in a new column.
I have a column "city", &...
- 638
0
votes
0
answers
49
views
Mapping groups' data on the map using Map.addLayer - GEE
I wanted to extract the areas of specific clusters. I asked this question. I wanted to extract the areas of object-based clusters but the answer I got, resolved my issue. I need to visualize the ...
- 25
0
votes
0
answers
39
views
How to preserve layers structure/groups when exporting GeoPDF from QGIS
I have a project with lines, polygons, points, GeoTIFFs and map services that are all organized in groups. QGIS can create a layered GeoPDF from them beautifully, but the resulted PDF won't preserve ...
5
votes
1
answer
114
views
Selecting N points within each geometry using SQL
I have grid and point tables in my Postgres db. The points are not equally distributed over the grid. The grid table is 100k+ geometries and the points are in the 100's of millions so efficiency ...
- 1,505
1
vote
0
answers
78
views
Using function "buildGeometry" of JavaScript library JSTS with 'ol.interaction.Select' and 'ol.Collection.<ol.Feature>' objects?
What type is the argument of a function "buildGeometry" of JavaScript library JSTS? How to use JSTS function "buildGeometry" with OpenLayers 3 selection, which is created is this ...
- 11
4
votes
1
answer
64
views
Grouping features with identical values in two fields and deleteing the geometry with the lowest value in the third field using QGIS
I've got a shapefile with three fields: "X", "Y" and "Z" they are the geometries as well but I also have them as field values.
Every line geometry in the shapefile has a ...
- 41
2
votes
2
answers
106
views
Looking for QGIS equivalent of ArcGIS "Group values" tool
I have LULC 8 classes. I want to group them in QGIS into five priority score classes in Symbology, just the same as the function in ArcGIS "Group values". But I can't find the same tool in ...
- 183
0
votes
0
answers
6
views
Can't aggregate data by date to calculate point path length
I have a table with the coordinates of the movement of the car, its id and the time the coordinate point was received. When I try to calculate the mileage of a car by grouping points by day, an error ...
6
votes
2
answers
257
views
Categorising data points along transect using QGIS
I have data on the latitude and longitude of several locations in Europe (blue). So far I have been able to read this data into QGIS but not more. I would like to plot a transect (red) and then ...
- 71
2
votes
1
answer
35
views
Combine features into new category
Within a vector layer I have dissolved 25k polygons into 43 different categories of land ownership (Ld_Use_Des). But now I want to further ''group'' them. For example I want to select Mineral Rights ...
- 605
2
votes
1
answer
141
views
Get a group from layerTreeRoot using its unique id using PyQGIS
I am having trouble when loading some layers in QGIS. I want to place them in specific groups and sub-groups but a problem occurs when multiple groups and sub-groups have the same name. The only way I ...
1
vote
0
answers
115
views
Group by multiple columns in QGIS array
I'm looking to create a figure with multiple rule-based symbologies. A graduated range within a category within a main category.
The only way I think that's possible is by adding categories, ranges to ...
- 11
2
votes
0
answers
50
views
Create variable containing the conditional mean of a group
I have a table with three columns, the first defining a group (Group), the second a characteristic (Species), and the third a numeric value (Height). I would like to obtain a fourth numeric column in ...
3
votes
1
answer
306
views
Create multiple callout lines from a single label
I would like to label groups of points (clusters) with only one label but several call-out lines. I built on top of the very appealing answer from @eurojam here: How do I give one label to two points?
...
- 303
1
vote
2
answers
132
views
Assign ID for coordinates with several points
In ArcGIS pro I have a point layer with XY-coordinates. At each coordinate there are several points with different timestamps. I would like to give each coordinate an ID, for example to be able to ...
- 33
0
votes
1
answer
285
views
Joining tables with GROUP BY in ArcGIS Pro
I have a layer "Table1" and an attribute table "Table 2" both stored in a PostgreSQL enterprise geodatabase, these 2 data have one field in common for which the cardinality of the ...
- 183
5
votes
2
answers
755
views
Groupping points to clusters containing similar number of features using QGIS
The question
Using QGIS, how to cluster unevenly distributed points from the same layer to groups of about the same size / containing the same number of features?
The problem
I have a large point ...
- 67.2k
2
votes
2
answers
946
views
Filling attributes in one field based on second field with same values in QGIS
How do I fill the attribute with "SID_2" of the captured image where the ID of "SID_1" is NULL?
I'm using QGIS 3.22
- 29
4
votes
1
answer
164
views
Calculating two columns at once in QGIS
Is it possible to calculate two columns at once?
So what I mean is that we have different covers and lengths and I want a total length of "Cover A" after that a total length of cover tb and ...
- 41
1
vote
0
answers
175
views
Group points based on proximity and equity using QGIS
I would like to group students based on the nearest school, but also having mixed social categories within the group of students.
I have x,y coordinates for the students and the shcool.
Each student ...
- 11
1
vote
0
answers
159
views
How to calculate sum of night light radiance for each feature in a feature collection?
I have a shapefile which contains 36 polygons (districts/counties). For each district, I want to calculate sum of lights (as well as count total number of pixels). I tried following code but failed. ...
- 105
4
votes
1
answer
143
views
Grouping lines by name and determining their proportions using Virtual Layer
I have a line layer with hiking trails. The hiking trails are divided into their surfaces. So one hiking trail consist of parts with different surfaces.
I would like to use a virtual layer to group ...
- 8,254
2
votes
2
answers
189
views
Selected item in layertree group or layer?
How do I check in PyQgis if the selected item in de QgsLayerTree is a group or a layer. I really can't find the answer.
- 455
4
votes
2
answers
416
views
Grouping and measuring total length of road based on specific attribute in QGIS
I have this dataset that describes the cycleways of a city.
I want to measure the km of cycleway for each type of highway (residential, track, unclassified, ecc) and then calculate the percentage of ...
- 161
5
votes
1
answer
906
views
Unsplitting/merging lines that have coincident endpoints using PostGIS
I have a large dataset of lines/linestrings (ie. a road network), which is unregularly segmentised/ split and the lines needs to be merged at coincident endpoints (if only two lines are touching). I'd ...
- 163
3
votes
2
answers
581
views
Summarizing fields with same ID in QGIS Field Calculator
I am looking for a command, that sums the value of the field "Baulast" if they have the same "ogc_fid" and if there is a Number in the field "WEA". If there is no number ...
- 317
3
votes
2
answers
722
views
Adding unique ID for consecutive groups using Field calculator in QGIS
I found a similar question on this site and the answer suggested:
array_find(
array_distinct(
array_agg("PortCluster_ID")
),
"PortCluster_ID"
) + 1
...
4
votes
2
answers
89
views
Replicating ArcMap legend in QGIS 3
I am trying to replicate this ArcMap legend in QGIS but i can't seem to get it right.
I am stuck in print layout and using QGIS 3. I have the title 'LEGEND' but i do not know how to categorize the ...
- 41
3
votes
3
answers
664
views
Counting and merging features based on attribute field in QGIS
I have a shapefile with a number of features, each with a field called "region". I want to count the number of features corresponding to each region. Outputting a shapefile with one feature ...
- 199
2
votes
0
answers
47
views
Dynamic buffer regroup [duplicate]
I am using QGIS 3.16 and I want to create a dynamic buffer around a layer of points, so that every time I move some point the buffer also moves.
I have succeed by duplicating the layer and then ...
- 51
0
votes
1
answer
168
views
Hiding/Displaying dashboard content (tiles) based on user or group logging in using ArcGIS JavaScript API
I want to know if it is possible to either hide or display the content of an Esri webapp, dashboard, or experience (tiles, widgets, data layers, filters) depending on which Portal user is accessing ...
- 1
2
votes
1
answer
146
views
Clustering of points but with a condition of not crossing set of lines
I have multiple sets of around 200-300 points and I have the following requirements:
Cluster the points in each set into a group of points with a minimum
& maximum number (as defined by me).
In ...
- 61
0
votes
0
answers
22
views
Which analysis to use? Analysing points' likeness across multiple fields including proximity. (AHP?)
I don't have much of a background in coding.
I have a point layer with 400 points. The attribute table contains 3 fields of interest:
Bearing (values between 0-180);
a Ratio (ratio of ellipse long/...
6
votes
2
answers
309
views
Counting fire occurences per county per year using QGIS
I wish to loop through this shapefile, and for each "COUNTY_NM", count the number of values corresponding to each "layer" value.
I want to output a CSV or equivalent which would be ...
- 199
1
vote
1
answer
710
views
Rename layers within group automatically by adding a prefix derived from group name using QGIS
I have some Sentinel derived rasters (time series) divided in tiles. In my QGIS (3.16) each tile is represented by a group. Each group contains rasters from different dates and according layernames. ...
- 477
0
votes
0
answers
84
views
Graphic grouping in QGIS Map Layout
In QGIS 3.18, I'm trying to draw symbols/graphic for Map Legend manually in the Map Layout. When grouping them, it shows the big box like the screenshot below and seems not convenient to continue ...
- 55
0
votes
1
answer
3k
views
GeoPandas TypeError: geometries are not orderable (numpy: TypeError: '<' not supported between instances of 'Point' and 'Point')
I'm trying to group rows of a GeoDataFrame based on a common gid value and aggregating two columns for which the values differ but I am facing this error:
TypeError ...
- 9,794
2
votes
1
answer
550
views
QGIS - creating a report from attribute table
I create a report from attribute table. At one column I have a name of a street, at second column I have a number. Relation between street and a number is one-to-many. Is there a function to show at ...
- 415
5
votes
3
answers
421
views
Generating unique code for features via grouping by several attributes
I have features with 3 columns of information ("material", "name", "dimension") in the Attribute table. I need these features to group - to create 4th column where ...
- 415
1
vote
1
answer
311
views
Dissolving polygons based on data values in GeoPandas
I have a long list of polygons in the GeoPandas GeoDataFrame (Sample below)
Index zone_name value geometry
0 A 100 POLYGON ((77.47638480859382 13.05584728590942, 77....
- 115
0
votes
2
answers
777
views
Sampling points in R with both distance constraint and group
I have a spatial point data frame with categorical variable as a column named "type", I would like to draw a random sample from these points (let's say 100 points) with maximum and minimum ...
- 160
4
votes
2
answers
698
views
Area of each polygon that intersects another layer and total area of intersections in QGIS
I have two layers: 'A' (orange) and 'B' (purple).
Using a Virtual Layer and group_concat I am able to list the polygons in layer 'B' that intersect with those in layer 'A'. I found that solution at ...
- 109