Questions tagged [aggregation]
To combine data into larger units. For example a group of points to a polygon, or political subdivisions (provinces) to larger entities (country).
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How to create one buffer around all the points using ogr2ogr?
I know how to make a buffer around each point,
$ ogr2ogr oom.csv a1.houses.csv -lco GEOMETRY=AS_WKT -dialect SQLITE -sql \
"SELECT ST_Buffer(GEOMETRY,.01,1) AS WKT FROM 'a1.houses'"
$ cat ...
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Fetch multiple fields in relation_aggregate expression
In the QGIS 3.34+ expression builder, how could one use the expression parameter in the relation_aggregate to fetch multiple fields?
E.g.:
relation_aggregate(
relation:= 'my_relation',
...
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What is the right way to dissolve vector features in GRASS GIS on attribute values of one column summarizing or averaging others?
The line product of v.overlay contains a column with zones number and a stack of other attributes.
What I want:
Dissolve features (lines) on attribute column that contains zones number. Other ...
2
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1
answer
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Aggregating points into polylines, sorted by timestamp using GeoPandas/Python
I have a geodataframe that contains positions (point geometries). For each position, we know the individual's id (id_individ), DOY (doy), year (année) and timestamp.
I want to aggregate the ...
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QGIS Field Calculator - Aggregating and Calculating Ratios Based on Y-coordinate
I am trying to use the QGIS Field Calculator to calculate the sum of a specific attribute ('demo_field') for features in a layer to the sum of the same attribute for features that share the same y-...
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Error using aggregate funtions in QGIS Geometry by Expression tool
I am encountering an issue while trying to use the make_line function along with geometries_to_array in the Geometry by Expression tool in QGIS. The expression I'm using is as follows:
make_line(
...
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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 ...
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QGIS multilevel query: aggregate values from different layers
QGIS 3.28.4. I have 3 shapefiles:
polyline, street information (streetId, + streetInfos...)
point, stake information (StakeId,streetId, + Stakeinfos.....)
polyline, pannels information (PannelId, ...
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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' :...
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Why is my custom aggregate function not returning data in the order I've specified?
I have a polygon layer where many features intersect each other.
I want to flatten these overlaps and pick out attribute values according to a custom order. To do this, I've been using QGIS's Union ...
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ArcGIS Pro: Aggregate Polygon using Aggregate Field not honoured
The aim
For cartographic purposes, certain features have to be generalized depending on the used scale. One step in this workflow is the aggregate polygons based on a category.
The problem
Using ...
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Expression works in one QGIS project, but not another
I have an expression in a Print Layout that populates a label with an attribute, based on which polygons are selected in map view. In the QGIS project that I made, it works perfectly. I tried copying ...
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Aggregate entities by single value distributed in two fields - QGIS
I have a polyline layer with unique value ("loop A"; "loop B", etc.) distributed between 2 fields just like this:
ID
Field 1
Field 2
1
Loop A
NULL
2
Loop A
Loop B
3
Loop C
Loop ...
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Cover area with point clusters bounds
Suppose, I have an area covered with regular grid points.
Points have some categorial attribute. I need to cover the area with polygons corresponding to the value of this attribute (it is like bounds ...
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Filling in attributes from a different layer in QGIS batch mode
I have a point layer with an X,Y field, containing the coordinates of each point separated by a comma.
I'm trying to batch process r.water.outlet based on these X,Y values from a different layer, the ...
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