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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35 views

Aggregating data?

I've been doing some practice exercises and I'm a little stuck on how to complete these exercises. The following coverages can be found in the PACD8 folder: PA_CD8_Voterfile=all registered ...
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1answer
58 views

QGIS tool for aggregating population data in fishnet

I'm looking for a tool or method to aggregate a vector fishnet based on a minimum value. Specifically, I have a fishnet containing a population value and I would like to join together cells that ...
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1answer
91 views

GROUP BY on geography in postgres 9.4.0 returns wrong/different results

table definition: CREATE TABLE search ( id bigserial NOT NULL, location geography(Point,4326) NOT NULL, location_aggregated geography(Point,4326) NOT NULL, created timestamp with time zone ...
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2answers
42 views

Can you do aggregate functions among nearby geometry in PostGIS?

I want to do aggregation based not on group but on geometry, is that possible in PostGIS? For example to calculate max, min, average price for all listings that's nearby a geometry point, how can I ...
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100 views

Simplifying geometries and calculating non-spatial averages

I'm quite new to using proper spatial tools, and have a simple question that doesn't immediately show up on google. I have a table that contains multiple rows of empiric data (say, speed of a ...
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2answers
59 views

Dissolving adjacent polygons and adding attributes

I am trying to merge together adjacent polygons and have the attributes added together for the merged features. The layer is of certain census blocks across a state (thousands of features) and I ...
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2answers
127 views

Aggregating satellite night light data in R

I am working in R and having some difficulties with extracting values from a raster layer. What I am trying to do is aggregate satellite night light data from pixel to polygons. However, when I ...
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1answer
31 views

Why am I getting small float numbers when aggregating points containing large integer values in QGIS?

I have a layer of points containing the centroids of European NUTS regions at NUTS 3, with population data in the atttribute table. I want to aggregate this population data to NUTS level 1, which is ...
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84 views

How to aggregate data which meet certain conditions using QGIS?

I have a point shapefile with meteorological stations which contains three columns, which are: Date: The date on which the measurement has take place (it covers a range of ten years) Id: The ...
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2answers
92 views

Method for automatic aggregation of polys with sparse data

I am part of a project on presenting health related data on maps. In order to maximize the analytical usefulness of the data, we wish to divide them into as small areas as possible. However, to ...
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1answer
43 views

How to use PostGIS for tile-based aggregation?

How can I create a tile-based aggregation of polygons with PostgreSQL/PostGIS? The input of such an operation could be the database table with the geometry and the data to aggregate, a bounding box, ...
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2answers
1k views

Dissolve/aggregate polygons with ogr2ogr or gpc?

I have a large number of polygons representing the boundaries of US counties which I need to merge into as few polygons as possible. Is it possible to do this with non-commercial software, or ...
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86 views

level of spatial aggregation of polygons

I am looking for a method that allows me to obtain the spatial aggregation of polygons for each cell of a grid with 10kmx10km resolution. In each cell (10kmx10km), I want to be able to consider that ...
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1answer
109 views

Spatial Aggregation of attributes from line structures in polygons

maybe someone has an idea how to deal with it (or directly knows the equivalent functions in PostGIS) for the following problem: I have a transport network (something like railways) and the ...
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3answers
150 views

Query to find the Intersection coordinates of multiple Polyon

I am using the below Query to find out the intersection coordinates of 2 Polygon and its working fine,but how to use or modify the query to find the intersection area coordinates for multiple(or N ...
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2answers
438 views

Postgis: aggregate function for intersection

I have a PostGIS Table with LINESTRINGS. I like to a query that returns all Roads that are connected. So I get a set of unconnected trees (in german 'Wald (Graphentheorie)') pseudo code: select ...
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2answers
2k views

Aggregating points to grid using R

I have a question with regard to spatial aggregation in R. What I am trying to do is aggregate a point dataset to a grid. I am unsure however how to do this as I have little experience with this sort ...
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2answers
704 views

UK Postcode District Aggregation

I've had a request recently to generate a map which includes UK Postcode districts, ie aggregations of postcodes based on the first section of the code (NW2, B1, E11 etc.). From what I've read, these ...
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2answers
228 views

how to aggregate raster values for each grid in a fishnet-like map

here is my problem: I have a raster layer containing the elevation info. and another gridded layer (shapefile type). What I want to do is to calculate the mean elevation within each grid to have a ...
3
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0answers
252 views

Area-weighted rasterising of polygon data

I'm looking for any GIS tool to do detailed rasterising of polygons. I've checked GDAL's gdal_rasterize command (and API), and ArcGIS's Polygon to Raster tool, but they only rasterise 1 attribute per ...
10
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2answers
446 views

Aggregating Polygons To Meet Privacy Requirements

I have a point feature class representing office locations of all employers in a certain industry. The feature class has an attribute for storing the number of employees working at each office. ...
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3answers
3k views

How to aggregate points to polygons using ArcGIS Desktop?

I am trying to aggregate my data points to the polygons so that I could find out how many points I actually have in each polygon, and then export the data contained within each polygon to further look ...