All Questions
152 questions
5
votes
3
answers
452
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
367
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....
- 125
0
votes
2
answers
968
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 ...
- 606
4
votes
2
answers
807
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 ...
- 119
0
votes
1
answer
59
views
Composite layer by distance
I've got a complicated problem right now. I have a layer with polygons and use the tool "Closest Neighbor" to find all Polygons that have a neighbor within 10 meters.
That works fine, but ...
- 41
1
vote
1
answer
882
views
Assigning incrementing id for each feature group in attributes with QGIS expressions [duplicate]
I have a layer with a repeating field name, thus different groups of features (I also have a numerical group field). How can I add a field group_id, using QGIS expressions? What I want is kind of a ...
- 75k
2
votes
1
answer
70
views
Grouping a dataframe whilst making a pie chart
I have a data layer which consists of an attribute table of ~30 columns and ~6000 rows. This table contains information about buildings that are located close to parks in Amsterdam. I want to create a ...
- 71
2
votes
1
answer
509
views
Group neighbouring features based on sum of attribute
Each polygon (building) contains "x" number of flats (eg "flat_num"=10 in one polygon/building).
I would like to group multiple polygons if:
the grouped polygons are neighbors
...
- 261
6
votes
2
answers
1k
views
Summing area of by several attributes in QGIS
I have a shapefile that contains building footprints with multiple addresses with different functions (with each an usable area). I would like to calculate the sum of the usable area, per building &...
- 261
1
vote
0
answers
2k
views
Exporting with QPackage or QConsolidate
I know there is a similar question, but it might be dated, and didn't completely answer my question.
I know of two plugins to export your QGis project, QPackage and QConsolidate. I'm not very familiar ...
- 157
1
vote
1
answer
126
views
Find Largest Building in each Parcel (largest feature in each groupby set)
I have a question similar to this one, but the proposed approach doesn't seem to work.
For context, I am new to qgis.
Given a set of parcels, each with 0 or more buildings, I want to select only the ...
- 139
0
votes
0
answers
120
views
Creating polygons from open ended line (riverine) feature
I have a dataset of rivers which I'd like to build into polygons of areas enclosed by rivers.
The rivers are continuous lines but there are open ends.
Is this possible? It's OK if the calculated ...
- 1
5
votes
1
answer
132
views
Copying all visible layers to new group
I would like to copy all visible layers in a project to a new group. Does anyone know of a quick way of doing this?
Background:
We have a Project that acts as a library for all the spatial data we ...
- 51
8
votes
4
answers
2k
views
Adding unique ID for groups of items using Field calculator in QGIS
I have a set of string values in a shapefile's attribute column and want to assign a number to them in a way that each unique string gets an integer number, like this:
How do I do this using the ...
- 125
0
votes
1
answer
134
views
Large-scale cloud masking, grouping and mosaic in Descartes Labs platform
I am looking to create a stack of cloud-free sentinel-2 imagery by day for a large portion of California for all of 2020 in the Descartes Lab platform. I realize that this is a very large amount of ...
1
vote
0
answers
82
views
Using a postcode sector map with a population attribute, create clusters of those sectors to have a total population within a defined range
I have a postcode sector map in QGIS and one of the attributes is 'population'. I am trying to create a map showing what postcode sectors would need to be clustered together in order to split the ...
- 29
2
votes
2
answers
532
views
Merging attributes of point features at same location
I have a CSV-file with all the facilities in an area, some sites have multiple facilities so at some locations there will be multiple points e.g. sports hall and swimming pool.
Is there a way to join ...
- 21
0
votes
0
answers
680
views
ArcMap - error 000728 field does not exist within table
I'm trying to join the table from Excel (my calculation about one region in Poland) to my shapefile (which contains whole Poland map and different calculations, so I need to attach a new table to be ...
2
votes
1
answer
339
views
Categorizing attributes by keyword in new field with field calculator in QGIS 3
So, the geological classification shapefile of the Philippines has the 'DESCRIPT' field which contains the geological time scale of each feature.
"Oligocene-miocene" and "Oligocene-miocene (igneous ...
- 1,217
0
votes
0
answers
93
views
Calculate frequency based on a filtered field, and put the value in another field
I'm a python beginner.
I'm working on one feature class, i would like to group this feature based on group_ID field, and then for each one of this group i would like to calculate the number of rows ...
- 135
4
votes
1
answer
868
views
Centroid of multiple polygons based on value in attribute table
I have a (polygon) shapefile with multiple zones. Now, I would like to calculate the centroid of groups of these zones. The zones have to be grouped based on a value in the attribute table:
AreaNr ...
- 123
3
votes
1
answer
1k
views
QGIS - SQL GROUP BY and MAX
I have a layer which contains a unique ID (UID) for each feature and another column of Scores.
For example:
UID, Score
A12,1
A13,1
A14,4
A12,2
A13,3
A14,5
I would like to use an SQL statement to ...
- 305
6
votes
3
answers
1k
views
Calculating Convex Hull based on attributes in QGIS
I have a layer with lots of (spatially grouped) lines - lines belonging to a group share the same value in a field.
I would like to create convex hulls around each of these groups using QGIS 3.8.
I ...
- 73
0
votes
0
answers
66
views
How to make analyzeGPS distanceGPS group by trip?
I have a dataset with id, lat, lon and time, where each trip has a unique id.
When I try to use mutate with the distanceGPS function in the AnalyzeGPS package and group by trip using this code:
gps%&...
- 11
1
vote
2
answers
241
views
Finding number of days per ID in table using ArcPy?
I need to count the span of days an individual has been observed, from the first til the last observation day. There can be many observations per ID per day and not everyday has observations, hence ...
- 13
2
votes
0
answers
186
views
Grouping layers by attribute value and finding nearest neighbour using QGIS?
I am new to QGIS.
I have two layers (layer_a and layer_b) consisting of two sets of points.
If I want to find the nearest point in layer_b for each point in layer_a, I can just use the Distance ...
- 121
2
votes
2
answers
85
views
Update 1 random value in a group of values
I have an attribute table with a date field and a random field. The date field has three different times for each day. I need to input a '1' in the random field for one of those three times in each ...
- 85
1
vote
2
answers
377
views
How can QGIS 3.X create atlas by a group field?
I have a line layer with 8 features and a field TYPE (5 features is type_A and 5 features is type_B). I want to create a atlas which output is two single image (one is grouped by typ_A with 5 features,...
- 213
0
votes
0
answers
645
views
Leaflet markers at same geo location (ClusterGroup)
I have a map created with leaflet with different markers. Sometimes the markers have the same (1:1) geo position.
I have already tested the great addon clustergroup, but I need the function to be ...
1
vote
1
answer
950
views
Group by variable and create layers from that in QGIS [duplicate]
I have a large shapefile with one layer with several variables. The shapefile has US block groups that I'll use for analysis. However, as I want to use this for leaflet, I would like to create ...
- 131
3
votes
0
answers
228
views
Clustering based on eqaul populations
I have a map of a city that is divided into 65 sectors (building lots in purple, sector boundaries in red):
In my shapefile of building lots, I have an attribute that is the total population within ...
- 427
1
vote
2
answers
99
views
Selecting features from grouped shapefile
I have downloaded some glacier outlines from the GLIMS database (http://www.glims.org/maps/glims) as a SHP file.
This contains multi-temporal data, that is, more than one outline per glacier (more ...
- 111
1
vote
0
answers
32
views
Grouping overlapping points by UTC Time, sum and average?
I have data from airplane calibrations where the plane flies in a crossing pattern; i.e. going E->W and W->E, then N->S and S->N.
I need to sum and average the values for both flights in each ...
- 379
9
votes
1
answer
3k
views
Creating Groups of points based on proximity in QGIS?
I have a dataset with around 900 points and I want to cluster them into groups of 44 based on proximity.
Is this possible in QGIS?
I have tried to use the convex hull tool with no success.
- 91
1
vote
1
answer
1k
views
Get child layers from a layer group
I'm using a geoserver and openlayers3 with html. I cannot find the way to obtain the child layers from a layer group. I have a layer group, and I show it in html perfectly, but what I want is to be ...
- 31
2
votes
2
answers
2k
views
Replace several coordinates by its mean value grouped by multiindex Pandas
I have a table with some info that are getting by a GPS, in my table I have this structure:
Date Time Latitude Longitude Accuracy Weather Visibility ViewPoint Species Bearing ...
- 458
3
votes
0
answers
215
views
Grouping neighbor points based on field sum in QGIS
I have about 14,000 points. These points have a specific field "time", an integer value, mainly between 1, 2 or 3.
I would like to split these 14,000 points into groups based on the "time" field ...
- 165
5
votes
1
answer
1k
views
Grouping GeoDataFrame by column while comparing feature area and adding values to new column with GeoPandas
I have these columns: "index", "area_of_poly", "cad_admin" in my GeoDataFrame, the dataset is available here: http://www.mediafire.com/file/x4q5k7xuztq6o3w/p.zip.
Now, I ...
- 463
1
vote
1
answer
2k
views
Extract and sort x coordinates in groups from a column to a new one in geopandas?
I am working with geopandas
There are these columns:geo,cat and I have to make the new column called
rank.
rank should contain according to the groups with the similar cat number an increasing ...
- 463
0
votes
1
answer
339
views
Filtering out clusters of features based on collective area threshold using QGIS/python?
I have a map I generated that roughly estimates timber industry land ownership (designated by the green on the map) in the counties surrounding the Salish Sea in the US state of Washington:
I want to ...
- 673
6
votes
1
answer
3k
views
r - Can dplyr::group_by work with sf::st_intersects
Trying to combine dplyr::group_by and sf::st_intersects to see which of the objects within groups in a sf dataframe are intersecting with each other but in the end all objects are compared with all ...
- 510
3
votes
3
answers
3k
views
Creating population dot density map at the block group level in QGIS
I'm new to QGIS, always used ArcMap, and I'm struggling to find out how to best display population density at the block group level for a county (the most granular level of detail for census geography)...
- 325
2
votes
0
answers
730
views
Clustering points into *n* number of groups of equal counts with ArcGIS
I have to divide points into groups. These groups will be used by agents to talk to property owners. The goal is to make the agent's job easy by grouping parcels that are near each other together, as ...
- 349
1
vote
2
answers
390
views
How to cluster/group points based on their frequency and event time without overlapping them?
I am trying to group around 100 points based on their frequency and occurred month (similar to https://i.sstatic.net/i7Mzi.png) but I haven't found a solution yet.
Tried many tools in QGIS but till ...
user108470
25
votes
1
answer
7k
views
Is it ok to group by geometry in PostGIS?
Is it OK to group by geometry?
We do a lot of counting points by polygon geometries, which involves intersecting the data first in order to count instances of students. by school boundary, block ...
- 18.9k
1
vote
1
answer
78
views
Reducing the number of records
I have a very extensive GPS track from which I am trying to reduce the number of plotted points. I though that I would be able to do so by grouping by a round of the timestamp /900 ( every 15 mins ), ...
- 141
5
votes
0
answers
2k
views
Clustering of events within a space-time window (R)
I am relatively new to clustering methods and am trying to determine the best method for clustering (or merely grouping) events that fall within a space-time window using preferably R. My goal is to ...
- 85
4
votes
1
answer
2k
views
Load Named Style within a group on QGIS
I am trying to apply the style from .qml to a group of layers in QGIS. I have tried to incorporate LoadNamedStyle within jkall's code here:
https://github.com/jkall/qgis-processing-scripts/blob/master/...
- 765
1
vote
1
answer
165
views
Grouping roads based on existing condition and AADT? (QGIS) [closed]
For QGIS software, I have municipality service agreement roads and an end-plan to group the roads based on close proximity (roads and communities close together or close to each other and on the same ...
- 11
1
vote
1
answer
1k
views
Grouping database results based on intersection using MySQL GIS?
I am using MySQL GIS (5.7.18).
I have a number of locations in the database. I also have a number of other polygons (not in the database).
I would like to perform a single query, intersecting all ...
- 111