Geographic Information Systems

Questions tagged [aggregation]

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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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Using Spatial Join, Dissolve and Aggregate in ArcGIS Pro ModelBuilder

I am creating a workflow using ModelBuilder in ArcGIS Pro 2.5.2 that will take updated parcel polygons and create/update the Zoning_Parcel (parcels symbolized at the parcel level) and Zoning_Districts ...
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28 views

Aggregate number of features by country in Overpass

Does Overpass (or Overpass Turbo) provide a mechanism for query like “show me the number of nodes tagged foo=bar by country”? Output being something like this: Country Count Estonia 5 Latvia ...
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Getting layer id of processing step in QGIS graphical modeler for usage within aggregate() function

How can I get the layer name or layer id of the result of an processing algorithm within QGIS graphical modeler, so I can use aggregate() function in a later processing step? Is this somehow possible ...
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Sum area of features intersecting atlas feature in QGIS

I have AOI layer named "Clusters" which is set as the Atlas coverage layer for my project I want to sum the area(Hectares) of specific intersecting features from my "...
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319 views

Using PostGIS to generate a polygon representing the area shared by some (but not all) of a set of polygons

I have an application where several users submit polygons, and I am looking to create an aggregate polygon that represents a kind of average of their submissions. We use PostGIS for our spatial ...
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51 views

Creating a new vector by aggregating another vector's value with a specific criterion in QGIS

I have a vector polygon layer in which each polygon represents an olive grove, each polygon has the data of harvestable biomass in that specific olive grove. Now I have to estimate transport costs ...
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1answer
27 views

Aggregate data from source value to mask layer by overlapping area

Let's assume I have a georeferenced data set seed_layer.geojson and a mask layer leech_layer.geojson. test_leech.geojson: { "type": "FeatureCollection", "features": [ { "type": "Feature", "...
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44 views

Ordinary Least Squares Point Aggregation

I want to run an ordinary least squares regression in ArcGIS Pro on my dataset which is composed of about 400 fire occurrences (point data) and demographic variables (100x100m polygons of income, ...
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Unioning PLSS Polygons

I want to union a set of Public Land Survey System (PLSS) polygons in a PostgreSQL/PostGIS layer, based on two fields, ‘sec_qtr’ and ‘qq’. A sample subset of polygons looks like this: I want to ...
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1answer
35 views

Aggregating pixels of raster dataset using ArcMap

*I am fairly new to working with raster data in ArcMap. * I have a raster dataset like in the picture I have uploaded, and you can assume that each individual pixel of the raster has a value which is ...
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How to add up election zone voting upto county level?

Sorry if it is a trivial question. I am trying to add voting data from election zone up to county-level using spatial join tool, but I cannot figure out which relationship I should use. When I use ...
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93 views

Aggregating numerous polygons into one with PostGIS

I have this PostGIS query which aggregates many polygons according to a variable ("region"): SELECT ST_AsGeoJSON((ST_Collect(polygons)),3) as geom FROM table GROUP BY region; The ST_Collect returns ...
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1answer
75 views

QGIS 3.14 vs PostgreSQL 11.5 : same query, different result

My layer has 82431 points. Each point has an attribute var with a single value a, or b or c,... I snap points, group by geometry and count the number depending the var attribute. So I start with : ...
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360 views

Get all related attribute values from features in list (QGIS)

According to this question: Get Attributes from 1:n relation in QGIS as Expression to use in Atlas I try to bulid waysigns for a hiking-GIS using the QGIS Atlas. The user should be able, to choose the ...
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47 views

Aggregate Willmott and Matsuura Temperature Climate Data on Country Level

I'm looking for monthly mean temperature data on the country-level since 1900, or at least 1950, with temperature weighted according to population density. The common database for the spatial ...
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Google Earth Engine Error when applying PCA on an aggregated image

I am getting this Error when applying PCA on an aggregated image using .median() method: Image.reduceRegion: Provide 'geometry' parameter when aggregating over an unbounded image. I have applied the ...
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640 views

Counting number of features within another feature using aggregating function in field calculator of QGIS?

My data: 1 polygon layer + 1 point layer My target: Calculate the number of points and the sum of a field within each polygon using the aggregate function in the QGIS field calculator. I know I can ...
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1answer
140 views

Assigning parent polygon using QGIS?

I use QGIS 3.8.0 and I'm looking for tools to assign a polygon parent depending on the value. I attach the picture, where there are several polygons with different names. I would like to get the name ...
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1answer
55 views

Generating map with polygon aggregation in PostGIS

Generate the map of federal units from the municipalities map in PostgreSQL with PostGIS. Example below: The table has only the geometry information and the "id". I tried: SELECT st_union(m.geom) ...
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1answer
157 views

Google Earth Engine, imagecollection aggregate_max (or min, or min), return null. What's the problem?

I am a little confused about this function in ee.ImageCollection: aggregate_max(property) Aggregates over a given property of the objects in a collection, calculating the maximum of the values ...
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1answer
50 views

Calculating new raster metrics without polygonizing in R?

I have an enormous number of large rasters representing tree canopies. Every individual canopy has a unique number that is assigned to each pixel that is part of the tree. I am working with R and the ...
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4answers
648 views

Count touching and near points for every polygon (QGIS)

I have a polygon and a point layer. The polygons contains buildings, the points should be the edges of the buildings. A building is "good" as much as points are touching or in the near (buffer 0.2 ...
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376 views

Aggregate functions in QGIS using spatial intersection

I am trying to compute a virtual filed using aggregate functions in QGIS (3.6). I want to compute the average on a field in the child layer based on the spatial intersection with the parent layer. ...
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2answers
115 views

Get attributes from touching lines in network - results seems random

This question is similar to this one: Get attribute from touching line layer (QGIS) but there is a new and more komplex problem in that context I need to solve: I have to plan drains, usually along ...
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1answer
142 views

Labeling polygons with the number of related table entries in QGIS

Using QGIS 3.6.1 I have a layer with areas and a table with entries related to the areas: A relation is defined like this: What I would like to achieve is to label the areas with the number of ...
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2answers
302 views

Rescale raster to custom resolution using sum as the function to aggregate

I have a 0.0083 resolution population raster dataset which I would like to upscale to a 0.5 resolution raster. In particular, I would like the aggregation process to sum all the 0.0083 pixels ...
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1answer
94 views

Count features in polygon by using aggregate (virtual field)

I have a points layer and a polygon layer. The points are placed randomly. Some are within a polygon, some are outside. I would like to write the amount of points inside each polygon as virtual field ...
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51 views

Trying to Count Number of Points within Specified Distance from Lines using Carto?

There were multiple points stacked on the same coordinates that I did not notice. I am trying to count the number of points within 10km of lines (routes) so the routes can be styled according to the ...
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2answers
264 views

Calculating point layer values within polygon features in QGIS 2

There are two layers polygon BereichBerechnung with a field "Are_Number" points EW2017 with a field "EWjeAdr" In QGIS with a Virtual Layer, I want to calculate the sum of the field "EWjeAdr" for ...
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1answer
216 views

Aggregating or summing field by two or more criteria using QGIS?

I am using QGIS 2.18. I'm trying to sum fields based on two criteria with filed calculator. I have the "ID" field and the "ZONE" field (ID is secondary key, repited for other table). ZONE field has ...
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1answer
595 views

Referring to the parent layer with aggregate functions in QGIS

I'm trying to find how to refer to a field of a parent layer as a filter for an aggregate function. The instructions specify that the parent layer can be referred to with the variable @parent, but I'...
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625 views

Correct resampling method to simulate lower resolution satellite data?

I would like to simulate lower resolution satellite imagery from continuous higher resolution imagery. For example I want to use Landsat derived leaf area index data with a resolution of 30 m and ...
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2answers
228 views

tool for point aggregation and mean calculation

I have the huge number of points spread across some map. Is it possible to calculate the mean value of a parameter in the points of a small area and make one point for the same so that the total ...
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2answers
290 views

Cartographic generalization: Dissolve “neighbour” / bordering polygon objects in QGIS

I have a polygon layer with buildings for the area of the whole city. My question is how to dissolve/aggregate/merge only those buildings, that are "neighbours", in a sense that they share at least ...
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1answer
159 views

Joining attibutes by location + aggregation per field

I am new to QGIS. I have a point layer (water permits) and several buffer layers (different distances from WWTPs). I can use "join attibutes by location" and find out the number of points and the ...
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2answers
98 views

Aggregating polygons with Basic level licence of ArcGIS Desktop?

I need to aggregate near-by polygons, but it has to work with a Basic ArcGIS Desktop Licence. I can't use the Aggregate tool (only Advanced) and I can't use the buffer tool, because the rounded edges ...
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1answer
281 views

Error concatenating lines in Oracle Spatial

The function SDO_AGGR_CONCAT_LINES is returning an error when concatenating lines from a table with simple line geometries (SDO_GTYPE - 2002): ORA-29400: erro do cartridge de dados ORA-06502: PL/SQL:...
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1answer
123 views

Aggregate and split layer by location into multiple layer in ArcMap? [duplicate]

I'm pretty new to GIS, but hope I'm moving in the right direction. I have a layer of the county map of LA, which is divided into communities and a layer of the building coverage of the county. The ...
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1answer
247 views

Creating an aggregate function filtered by entry value

Can anyone help me parse an aggregate function for Qgis 2.18 which sums the values of one field, for all entries which match a value of the entry in question. So, for example if I have a simple ...
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1answer
135 views

Aggregating/Averaging NDVI across pixels. Arithmetic mean seems bad choice

I need to compute an aggregate index for vegetation density in certain (large) shapes, to assess desertification. I have NDVI data at a high spatial resolution (~100 NDVI-pixels per aggregation shape, ...
3
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1answer
211 views

How to calculate the number of polygons along a line segment in QGIS

The image below is a representation of a digitised urban area derived from Google Satellite and OSM. The black lines between nodes are street segments and the irregular polygons are households. I ...
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1answer
230 views

Aggregating strings in QGIS

My inputs are in this way : col1 col2 col3 1 a c 1 b c 2 c c 2 d b 2 e z And I would like to obtain : col1 col2 1 a, b 2 c, d, e I ...
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1answer
155 views

Working with Sentinel-2 data and aggrigation in R

So I was wandering if there is a way to simplify a couple of Sentinel's rasters so I can apply raster analysis on them. Problem is that whenever I try to aggregate the data my RAM, CPU and storage ...
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1answer
124 views

Visualize challenge: show origin of aggregated minimum r.series job

Using r.series with the aggregate minimum option I'm merging multiple viewshed results to visualize how much vertical space a development area has for new buildings. Meaning that a part of the height ...
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1answer
136 views

Expression Builder in QGIS in editing Attribute Table

I am working with a simple attribute table that has 4 columns; 'Xcoord' 'Ycoord' 'id' 'id2' 'id2' is a new field that i added to the attribute table. 'id' is a field showing land use classes with ...
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1answer
2k views

Aggregating raster using GDAL?

I have a GeoTIFF which is at 30m resolution. I need to downsample it to 250m resolution (using some aggregating function such as mean, mode, sum). My stack is python (rasterio and GDAL bindings) I ...
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459 views

Is there a way to retrieve shapefile attribute table information for a given coordinate in R?

Does anyone have an idea how could one get information out of shapefile attribute table (class SpatialPolygonsDataFrame in R), in my case data from column that contains species names, based on a list ...
3
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1answer
162 views

Aggregate polygons in edit session using ArcObjects and c#

I want to aggregate some polygons in edit session using ArcObjects and c# language. In other words, my purpose is to use methaheuristic algorithms for polygon aggregation. So, I want to aggregate some ...
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375 views

Aggregate Lines Based on Distance between Segments

I have a VectorTile basemap that I am optimizing, (working on reducing the size of individual tiles), the major chunk of tile size is road data (geometry and attributes). I am working on simplifying ...
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1answer
311 views

Aggregate by date-time and compute a centroid as an output?

(I would prefer using R if possible) I have a table with coordinates (in latitude, longitude), time information (YYYY-mm-dd HH:MM:SS) and ID information (example provided). I sometimes have multiple ...

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