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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R {spdep} Get list of neighbors from nb object

I want to identify the specific neighbors of each polygon within a SpatialPolygonDataFrame from nb object. I know I can get the number of neighbors by polygon id by card(nb), but how to get the list ...
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31 views

How to find closest point on a line from a point in Oracle Spatial?

I want to find the nearest point on a line from a point in Oracle Spatial. I know how to do in SQL Server and PostgreSQL but could not find anything about Oracle. I have used MDSYS.sdo_nn to find the ...
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56 views

QGIS - How to find the distance for the nearest polygon from point for a defined angle?

I'm using QGIS 3.1 and I want to find the distance from a point to the nearest polygon for a given direction. So for example, for each point in my point layer I want to find the distance to nearest ...
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50 views

How to find nearest neighbor in Oracle's ST_GEOMETRY?

I am trying to find nearest road segment to a point in Oracle. I can do this with SDO_GEOMETRY type i.e select /*+ LEADING(pois) INDEX(route ALL_ROUTES_SPTAIL_INDEX) */ route.* from DEVICE_STATUS ...
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Distance Point x,i from nearest Point x,j report Point x,j ID in r

I have a sample of points villages x,i, and I want to know the distance between each village x,i and the nearest village x,j. The i, and j depicts two different samples. I am able to find the distance ...
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12 views

Linking clusters and masks by a common identifier

In ArcMap, I have raster clusters with unique identifiers. Around each cluster I have masks. Is there any way to carry each of the clusters' identifiers over to the attribute table of its closest ...
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30 views

Cut hole in raster with shapefile and sample at closest edges

I have a raster in which I'd like to cut a "hole" with a shapefile. I have points close to the boundary, but inside the hole, and I would like to find the closest point on the edge. To give a concrete ...
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35 views

ST_ClosestPoint() moves all points to one line instead of closest line

I have a line network and I've created evenly-spaced points along those lines. The problem is that the points are not exactly on the line so subsequent overlay operations will not work as expected. I'...
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199 views

Rockfall analysis (Nearest neighbor downhill) in QGIS

I am working on a rockfall guide for QGIS and I'm currently stuck on one of the stages. I currently at a point in the guide where I have two point layers one "rockfall release point"-layer and "...
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28 views

Nearest Neighbor Two Point Tables Return Line Geometry

I am looking to find the nearest neighbor between two point tables in PostGIS and return the ids of both along with the line geometry. I have been able to determine the distance for the nearest ...
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1answer
93 views

Spatial 1 to 1 join by proximity in sf and R?

I'm trying to join a Simple Feature of POINT geometry type to another Simple Feature of POLYGON geometry type using st_join and nngeo::st_nn as the person asking this other question also did. The ...
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Nearest Neighbour along a route instead of geographical displacement

Say that I have three layers as follows for a certain region: Line Layer representing roads Point Layer representing hotels Point Layer representing train stations Using QGIS is there a way in which ...
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72 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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59 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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162 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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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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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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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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33 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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95 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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1answer
45 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
588 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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182 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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49 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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229 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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30 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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675 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
547 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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1answer
61 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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278 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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175 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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319 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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453 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 ...
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2answers
291 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 ...
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199 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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1answer
190 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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168 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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203 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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167 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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88 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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1answer
105 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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252 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 ...
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212 views

Optimizing a nearest neighbor search in PostGIS for a large dataset

The below code is working well for smaller datasets, however I want to use this with a 30 GB table. Every time I run it using the larger table I run out of SSD space, the table gets to 127 GB in size! ...
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2answers
565 views

Nearest Neighbor

We've got a table of approximately 300,000 points and would like to find the nearest neighbor (within 10km) to each point in the same table. The most efficient query we've found so far is below, but ...
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250 views

Find the nearest neighbour for points in one layer to points in another, then measure the distance

USING QGIS 2.18.19 with python console (planning to upgrade to the newest QGIS after this piece of programming) I am struggling with finding the correct pyQGIS coding for this. I have a shapefile ...
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208 views

For each row of GPS coordinates, get value from nearest road to coordinates and copy to said row using PostGIS? [closed]

I have two tables in my database; one contains a set of GPS coordinates of a car which have been converted to geom, and another containing Open Street Map road data, including the speed limit for most ...
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1answer
342 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 ...
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65 views

Get barrier edge id

I have a table of POINTs that represent barriers. I would like to be able to find the closest edge id on the edge graph so that I can have the routing algorithm ignore that edge (thus route around it)....
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1answer
172 views

QGIS 3.0.2 NNJoin doesn't complete. Crashes when close status bar

I have run a large spatial point to polygon join of 2 million points to 657 polygons. I used NNJoin so that the closest polygon will be assigned to a point if the point does not lie within one. The ...
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2answers
172 views

Nearest Neighbor search in PostGIS using cases

I am using the following PostGIS nearest neighbor query to determine how close a point is to an area (polygon) that has been flooded and it's working well: SELECT ST_AsText(ST_SetSRID(...