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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108 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 ...
3
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1answer
81 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 ...
2
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1answer
40 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
44 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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0answers
15 views

Line segment overlap aggregation / analysis in Python?

I have a large sample of gps coordinates, and I would like to create a similar analytical visualization to that in Overlaying lines and aggregating their values for overlapping segments using R? Does ...
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0answers
20 views

Reclass raster map areas smaller than specified area size

I need to reclassify raster areas smaller than 100m2 (0.01 ha) to new ones. r.reclass. area from GRASS GIS does the job for some raster sizes, but simply stucks/doesn't work on bigger ones (54000 x ...
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1answer
34 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 ...
2
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4answers
289 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 ...
3
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0answers
125 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. ...
2
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2answers
99 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 ...
4
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1answer
74 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
81 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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18 views

When using Aggregate Polygons tool in ArcGIS Pro, some new shape areas and length result in zeroes?

I used the "Aggregate Polygons" tool to aggregate 265 polygons, and the tool gave me 268 new polygons, but 80 of them display a shape_area and shape_length of zero. When I try to calculate area for ...
2
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1answer
68 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 ...
0
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1answer
37 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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56 views

Extraction Burned Area from MCD64A1 for Region

I would like to extract burned area and burn date information from MCD64A1 MODIS Collection 6 global burned area product. The data is in monthly composites with burn dates in julian days. I need it ...
2
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2answers
166 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 ...
3
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1answer
133 views

Line width and labels based on blended values of features sharing same geometry in QGIS

I want to appropriate line segments that share the same geometry with a particular line width and labels based on the aggregated values of one field "GIS@BUS_5_Min". My attribute table and polyline ...
0
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1answer
86 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 ...
3
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1answer
249 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'...
2
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0answers
350 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 ...
2
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2answers
140 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 ...
2
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2answers
194 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
65 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 ...
3
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2answers
62 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
168 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/...
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1answer
50 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 ...
2
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1answer
170 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 ...
2
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1answer
106 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
195 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 ...
3
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1answer
124 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 ...
2
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1answer
96 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 ...
4
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1answer
104 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 ...
2
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1answer
107 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 ...
5
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1answer
1k 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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0answers
211 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 ...
2
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1answer
123 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 ...
12
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2answers
292 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 ...
1
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1answer
293 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 ...
0
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1answer
35 views

Filtering out class from high resolution map in lower resolution map?

I have a soil sealing fraction map (SSF) with a resolution of 30 meters and a high resolution land cover map (HRLC) with a resolution of 5 meters. I would like to use the HRLC map to filter some ...
1
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1answer
931 views

R spatial aggregate, IDs out of order

HUC12_intersects is a SpatialPolygonsDataFrame object with over 5000 polygons library(rgdal) library(sp) library(rgeos) library(raster) library(maptools) HUC12_intersects@data AREA_ACR_1 GEOL_CODE ...
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2answers
754 views

Aggregation of MODIS 16 days data to annual data set

Is there a way to calculate mean annual NDVI and mean annual EVI from the time series MODIS images (2000 - 2016). I have gridded data downloaded to the local drive. Planning to use R for this work.
3
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1answer
179 views

Change raster cell size while keeping attributes

I have a raster with a cell size of 1 and I want to increase the cell size to 5 so I use the Aggregate() function in ArcMap 10.4. The problem I'm seeing is that after processing I lose the desired ...
2
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1answer
55 views

Aggregating georeferenced point data to conflicts site using R

I have a question with regard to joining to datasets. On the one hand I have information about the location of a conflict regarding its lat/long, radius, and area and how it changes over time. Here ...
6
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2answers
3k views

Mean by month on R stacked raster

I work with MODIS NDVI rasters in 2016. I have 23 rasters stacked in one object. I have 2 raster by month. I would like the average by months and conserve a raster for each month. ndvi.stack <- ...
4
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2answers
372 views

Aggregation of multiple POSTGIS records in Geoserver

I have a WMS layer which geoserver fetches from a postgis layer. For a given query to this layer I might have two records for a given geometry. The record contains geoshape and value where value is ...
8
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1answer
3k views

Calculating Optimal Geohash Precision from Bounding Box

I'm using Elasticsearch's GeoHash grid Aggregation to plot clusters on a map (using Leaflet). I understand that for larger areas a lower precision setting should be used to limit the number of buckets ...
2
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0answers
71 views

Is aggregating points to areal units ever useful - Spatial statistics

I have a large point dataset of a population (By population, I mean that it was not a sample e.g. all houses in a county with an attribute such as size, price, age, etc.). Each point represents each ...
1
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1answer
2k views

R - aggregate with additional argument

I would like to use the function aggregate (R raster package) to assign to a grid point of the new raster the number of grid points of the old raster that have a certain value for(val in 1:10) { ...
1
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1answer
70 views

Sum of features from one layer to another

I have two different shapefiles and I work in Arcmap. This is what I have: The areas in picture 1 are smaller areas and the areas in picture 2 are in an aggregated form. File 1 contains number of ...

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