Questions tagged [nearest-neighbor]

A technique for resampling raster data in which the value of each cell in an output raster is calculated using the value of the nearest cell in an input raster.

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1answer
39 views

ST_Distance does not give nearest node

I am trying to find the nearest point on the road network closest to a given point. I imported the road network into PostGIS from QGIS and am using the SQL window in QGIS DB Manager to query the road ...
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1answer
32 views

Distinct st_shortestline

I have 61 pts and numerous rds. I would like to find the shortest distance to the nearest road using st_shortestline. I need 61 unique line segments, one for each point to its nearest road. Instead I ...
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1answer
99 views

Calculating nearest neighbor within each polygon using QGIS?

I have 3 layers: world map divided into countries; layer of points representing cities; layer of points representing conflict events (e.g. firefight). My goal: For each city, calculate the nearest ...
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2answers
78 views

Calculating distance between multiple lines of points in QGIS?

I'm looking to calculate a distance from a sensor reading to that of the nearest sensor reading on a different sensor line, all held within the same points file. Ideally using QGIS. The image below ...
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2answers
699 views

How to UPDATE with LATERAL Nearest-Neighbour query?

Say I have table gps like: CREATE TABLE gps( gps_id serial primary key, measured_timestamp timestamp, geom Geometry(Point,4326), stop_id int --Null ); And I have a table of stops like: ...
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1answer
51 views

Error creating DEM with Nearest Neighbour tool in QGIS?

I have an issue when I am creating a DEM with the tool natural neighbour on QGIS. When I extract my data directly on Qgis I have no issue creating a DEM. My points are coming from different sources ...
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0answers
30 views

NearestNeighbor producing bad quality tiles

I have been using Bicubic interpolation to render some basemaps because this produced good results. This is what I get when using Bicubic: However, when using Nearest Neighbor interpolation, a white ...
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1answer
25 views

Seeking package/function in R that can help tag GPS coordinates of fauna sightings to nearest sampling point?

I have 1 dataset of animals sighted walking a survey, and I would like to tag them to the respective sampling points along a transect. Any idea what function/package in R can do that? Maybe ...
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1answer
56 views

Nearest Neighbor - return object ID in R

I have a csv file that contains the GPS coordinates of about 100 villages and their unique ID. I have an other csv file with the GPS coordinates of some potential destinations and their unique ID. I ...
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31 views

Finding nearest 10 observations that occurred 2 years before original observation using ArcGIS Pro ModelBuilder?

I have a point sample of house sales (~42k points over 9 year period) with a date field(integer), and for each point I want to find the 10 nearest houses within a year of sale and also which were sold ...
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1answer
18 views

How to get Memory layer dispalyed in Vector Panel List using Pyqgis?

I have two point layer in my Project Centroid.shp and Nodes.shp.I have used Distance Matrix to find nearest Nodes point from Centroid Point. I have saved the output in FinalDistance.csv. The ...
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1answer
24 views

Neighborhood Analysis with ArcGIS Spatial Analyst to Calculate Percentage

I have a raster file where the cells (1 meter) are classified as 1 (forest) and 0 (non-forest). I would like to create another raster (1 meter) where each cell is given the percentage of cells within ...
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2answers
182 views

Combining st_join with st_nn to include all points within, as well as within a given distance of a polygon

This is a follow up to my earlier question (Spatial join in R - Adding points to polygons with multiple corresponding points). I have successfully joined a spatial points file to a polygon file in R ...
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1answer
188 views

PostGIS -> LineString + PointZ = LineStringZ

DATA I have 2 tables in PostGIS: linestable with MultiLineString geom surveypointtable with Point + elevation attribute GOAL The goal is to rebuild the lines as 3D replacing line's vertices with ...
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4answers
24k views

PostGIS nearest points with ST_Distance, kNN

I need to obtain on each element on one table the closest point of another table. The first table contains traffic signs and the second one the Entrance Halls of the town. The thing is that I can't ...
2
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1answer
363 views

Matching two point clouds without loss (nearest neighbor, but more complicated) [closed]

I have two point clouds, one with demographic and one with electoral data. Points in both clouds represent the same empirical entity (say, a village, or an urban neighbourhood), but are not in the ...
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1answer
6k views

Finding Nearest Line Segments to Point using shapely?

Background From a known Point, I require to establish the nearest surrounding "visible perimeter" against a table of MultiLineStrings, as shown on the diagram. I've searched this site with a number ...
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1answer
181 views

KeyError: u'M' in Average Nearest Neighbour test

When I try and run the Average Nearest Neighbour test on my Shapefile I get the error: KeyError: u'M' Failed to Execute (AverageNearestNeighbour) On a "normal" Shapefile this works fine. However I'm ...
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1answer
186 views

Spatial Analysis - Identifying Regions with Common Boundaries

I have the shape file for DC PSA's as defined in 2012 (see below). I would like to be able to identify in semi-automatic fashion which PSA's are neighbors - that is, which PSA's are nearest neighbors ...
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1answer
117 views

Find the closest Point from a Point which contains the same attribute

I am trying to create python code to iterate through points on 1 layer and find the closest point on another layer (Road Chainages) based on attribute values. I need to limit the search to < 20m ...
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0answers
43 views

PostGIS - Nearest Neighbour Join to sum values

I have a table of polygons T1 and a second table of points P1 Each point has a value I want to sum the values of P1 for each T1, with P1 being the closest set of points to T1 At the moment the only ...
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1answer
529 views

Classifying raster that takes neighbours into account?

I am working on classifying forest types using Sentinel-2 satellite imagery (10-m resolution; band-2, band-3, band-4 & band-8). I have ground-truthed field data as a training set. I want to set a ...
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1answer
305 views

Spatial join attributes based on closest point in PostGIS

I have two point tables from which I want to extract a value from one table to the other, based on the nearest distance of those two points. t1 t2 id | value id 1 | 100 1 ...
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2answers
162 views

Classifying neighbors AND neighbors of neighbors using ArcGIS Desktop?

In ArcGIS 10.2, I'm trying to identify the neighbors AND neighbors of neighbors for counties in the United States. Although I can identify which counties are neighbors to each county using either a ...
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0answers
433 views

Nearest Neighbor Analysis Results

I'm fairly new and entirely self-taught in using QGIS 3.4. I'm looking at turtle nest sites and trying to run a nearest neighbor analysis to analyze their distribution and establish whether or not ...
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1answer
45 views

How to find the closest stop point PostGIS

I have Point geometries created from lat,lon I loaded all the 10,000 stops in a certain city using gtfs i would like to query my db to find the closest stop reference to my point. the staypoint ...
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0answers
91 views

Applying Edge Correction in ArcGIS Average Nearest Neighbor?

I am using ArcGIS 10.3 with the tool Average Nearest Neighbor from the Spatial Statistics toolbox to describe the data. I want to avoid mistakes caused by Edge Effect. In the Ripleys K Function tool ...
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3answers
514 views

Clustering neighboring points inside ArcGIS Desktop?

I am using ArcGIS Desktop 10x. I have a shapefile of 300 points which I need to make groups, each of which will contain exactly 9 points which are closest neighbors. I tried the 'near' tool, ...
5
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1answer
69 views

Getting the distance traveled across road segments

so I have a query that takes an encoded polyline, segmentizes that polyline into smaller pieces, and matches each point on that segmentized line to a "road segment" from a separate table in my ...
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1answer
144 views

SRTM/DEM 1m resolution (batymetri) to point [closed]

I have bathymetry data (1 huge data) = SRTM/DEM/FGDBRaster (0,9818m resolution pixel, floating, 32 bit, 45 GB size) and an alternative data (split into small pieces data) = same data but with 1m ...
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1answer
434 views

Finding the nearest line to a point in QGIS,but Not Work

I saw Finding the nearest line to a point in QGIS? I wanted to create a program to get the line closest to the selected point. Here is the code. dPos = mouseEvent.pos() qpoint = ...
3
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1answer
381 views

Merging overlapping polygons with original polygons in QGIS

I have a large vector shapefile dataset containing polygons, many of which overlap. I want to assign each overlapping section to one of the original overlapping polygons. E.g. if polygon A overlaps ...
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0answers
187 views

Finding the closest points to a line with only one point from each subset of points

I have a set of data points that represent many paths for different journeys, where each journey has its own identifier (Operation No). The data for all journeys is in a single table but in effect has ...
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1answer
239 views

A line between point to nearest neighbour point using QGIS

I have a layer of points in QGIS which represent electric poles How do I create a polyline layer that would have lines running between the poles so it can represent the the electric cables that ...
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2answers
185 views

Excluding point from Nearest neighbor search once it's been matched using R?

I have two lists of addresses, List 1 and List 2. I want to find the nearest neighbors of the list--but without assigning more than one point to any point. So say point 1A is the nearest neighbor of ...
2
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1answer
290 views

Efficient way to find nearest feature between huge postgres tables

I have two tables (g1 and g2), both with around two million features. I need to know for each feature in g1, which is the closest feature from g2, with a condition. Since they are both so huge, I also ...
4
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2answers
146 views

Query takes very long time

I'm a newbie to POSTGIS and I wonder if someone could help me out. I have loaded all postal codes with their geographical coordinates (geography) and created an index on this coordinate. When I run ...
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2answers
755 views

Why does QgsSpatialIndex.nearestNeighbor(point, 1) sometimes return 2 lines?

I'm trying to get the closest line to a point using PyQGIS in a plugin. The active code file is this: http://pastebin.com/TDzmsKVM When I request the closest line (only 1) nearestIds = self.spIndex....
3
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1answer
124 views

Get closest road-segment to segmentized LineString points

So I have a table that stores a bunch of traffic counts for various road segments across the country. I'm regularly getting real-time location data from vehicles that are moving around a given region ...
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3answers
1k views

Calculating spatial lags per year in R

At the moment I am having some difficulties with calculating a spatial lag in R. I know how to calculate the lag in space-wide format but am unable to do it in long form, i.e. have repeated ...
0
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1answer
81 views

Query to return closest LineString given a Point [duplicate]

I have a road lines data in a table with field roads(id SERIAL ,the_line geometry(LineString,4326)) suppose an accident occurs in a middle or at any location in that waterline i want to stop the ...
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0answers
141 views

Interpolation in QGIS shows wrong output result [closed]

I have done interpolation (IDW and Nearest Neighbour) in QGIS. But interestingly the output shows the wrong result. The area where I have a huge number of points results in a lower Z value (it is ...
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1answer
63 views

No module named 'mmqgis'

I have two layers in my Project 1)Points Layers 2) Polygon Layer I need to apply nearest neighbour Analysis between point and Polygon, but i am unable to get . I tried the below code.I am using ...
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0answers
122 views

Nearest Neighbour Analysis Or NN join

I have two Layer in my Project 1) Voronoi Layer which is constructed on point Layer 2) Building Layers which is represented as Polygon. The goal is to find the nearest node for every polygon (...
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1answer
99 views

Constructing Voronoi Polgon and Applying Nearest neigbour in it

I am learning QGIS 3.XX and currently working on Voronoi Polygons. I have three layers Point layer Building Layer Population CSV file. These points layer are basically water tanks and building ...
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0answers
198 views

Geo-hash finding nearest neighbour with massively variable distance to actual nearest neighbour

I have a series of points in lat-long space, ranging from having their nearest neighbour very close to 1000s of km away. Say I do a geo-hash of these to a high precision, my search of nearest ...
2
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3answers
560 views

Projecting GPS point to point in closest pgrouting road (map matching)?

I'm quite new to PostGIS and pgRouting. I'm interested in doing a simple map matching. Precisely, finding the closest point in a given OSM road network. I’ve successfully imported the OSM network ...
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1answer
105 views

Intersection with closest point using PostGIS?

I'm trying to update the field of a point table with a value from a linestring one : update object_elevation set contour_elevation = c.contour from contours c where st_intersects(st_ClosestPoint(c....
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2answers
149 views

ST_ClosestPoint usage in QGIS 3.0

I try to use ST_ClosestPoint function to find the closest point to find the MultiLineString layer. My line layer (Reach) has 42 attributes and point layer (Stations) has 7 attributes. My code is: "...
1
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1answer
266 views

Nearest point on line from a point in PostGIS and its attribute value

Consider the following image; I have points (shown in blue circles) stored in my database with their geometry and an attribute value. Additionally, I have another table with User Points (yellow ...