The measure of separation between two entities or locations that may or may not be connected, such as two points.

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4
votes
3answers
546 views

How to efficiently find points within an elliptical area?

Using PostGIS 2.0.0 I need to filter the results of a function, which returns many POINTs, to find the ones that lie within an elliptical area defined by two points and a distance (all parameters ...
3
votes
2answers
1k views

Calculating the distance from each point in one layer to the nearest point in another layer

I am trying to find the average distance from several points in a layer to points in another layer. I am using ArcMap Basic - I know there is a way to do this using the Advanced version of ArcMap but ...
2
votes
2answers
126 views

Calculate nearest distance in ArcView, XY coordinates

I am really lost and struggling because I have never used an Arc system before. I have two datasets. One with house locations, and the other with investment locations- each locating by XY coordinate. ...
2
votes
1answer
513 views

geotools Linestring distance in meters

I want to use geotools for working with gis data. I'm most concerned about distance calculations, not so much about drawing a map. What I still couldn't figure out is how to make distance calculations ...
2
votes
1answer
362 views

Finding distance between consecutive points using ArcGIS Desktop?

I am wondering how I can get the distance between consecutive GPS locations in ArcMap 10 (i.e. the distance between consecutive GPS locations sent in during a wildlife telemetry study).
2
votes
2answers
907 views

Calculating millions of distances with Road Graph

I'm new to GIS but thanks to the answers I got in another question here on GIS stack exchange I was able to increase my knowledge significantly. This question is related to an earlier question I asked ...
1
vote
1answer
291 views

Converting from kilometers to degrees distances?

We have geometries in a Postgis database with SRID WGS84 and we have found lookups directly in degrees to be much faster than in kilometres, because the database can skip the projections I would ...
1
vote
1answer
66 views

How to calculate the shortest path to pass on 7.000 UTM points?

Anyone can give me an advice how to calculate the shortest path with a lot of UTM points? In total I have 7000 points, but it can be grouping 100 or 500. I have knowledges about Java and Python for ...
18
votes
5answers
12k views

How to cluster spatial data in R?

I am very new to R, so please bear with me : > I have bunch of data points with latitude and longitude. I want to use R to cluster them based on their distance. I have already taken a look at this ...
8
votes
4answers
2k views

Looking for a fast, open-source raster cost-distance function to use in code

I've been scouring the internet for a fast, open-source cost-distance function that I can embed inside my code. The functionality should basically work like the ArcGIS implementation where I can ...
3
votes
2answers
991 views

Total great circle distance along a path of points (PostGIS)

I am looking for an SQL query that sums the distances between a series of points using PostGIS. The situation is as follows: I have 2 tables: tracks and points. Points belong to a track and thus ...
4
votes
4answers
3k views

Calculate min distance between points in PostGIS

I have point layer in PostGIS database. Help please with query which add for each points in layer distance in attribute table between this point and another nearest point. Thanks! Update Calculate ...
15
votes
2answers
3k views

What is the approximate error of the Pythagorean Theorem vs. Haversine Formula in measuring distances on a sphere at various scales?

Many people when first trying to calculate distances between two longitude / latitude pairs ask if Pythagorean theorem works as an appropriate distance function. Most often people answer "no, the ...
8
votes
1answer
1k views

PostGIS - Calculate progressive distance between points on a GPX path

I am attempting to build an elevation profile using PostGIS-PostgreSQL only. I have imported GPX data in my PostGis database, so now I have a table full of the GPS coordinates of the track and the ...
4
votes
2answers
211 views

Measuring distance to roads using raster data in ArcMap?

I am using ArcMap 10.1 on a Windows x64 system. I am trying to analyse the driving force of urban land use land cover changes. I have 7 raster files represents distance to roads, distance to river, ...
10
votes
2answers
1k views

Surface distance on DEM between two coordinates

Given two coordinates on a digital elevation model (DEM), how do I compute the actual distance traveled between the two locations, assuming a straight line route? How will changing the resolution of ...
9
votes
1answer
1k views

Analysing movement using cost surfaces with ArcGIS Path Distance tool?

I would like to analyse hypothetical movement (on foot) in a landscape as based on energy expenditure, but I have run into some trouble that I am hoping that you could help me with. I have tried to do ...
8
votes
1answer
511 views

How do I calculate Manhattan distance with PostGIS?

I am using the ST_Distance function to calculate the distance between two geometries (a train station and a building) Since I know that all buildings and all train stations are in Chicago, which has ...
8
votes
5answers
5k views

Calculate distance in km to nearest points (given in lat/long) using ArcGIS DEsktop and/or R?

I have two point datasets in ArcGIS, both of which are given in WGS84 lat/lon co-ordinates and the points are spread across the whole world. I would like to find the nearest point in Dataset A to each ...
8
votes
3answers
808 views

Identification of consecutive points within a specified buffer

I have a point file, hourly relocations of an animal, and I want to be able to place a buffer around each point and calculate the number of subsequent points which are within the buffer zone. I am ...
4
votes
1answer
215 views

Identifying south facing mountain land, above an elevation, within a slope range, less than fixed distance from major roadways

This odd question comes from believing that such an analysis is plausible in a GIS system. Only, I don't how to accomplish the various discrete steps implied from the Title, nor where to get a topo ...
3
votes
2answers
110 views

Measure distances between specific features in QGIS for Desktop

I'm completely new using PyQGIS and developing plugins, and I would appreciate some orientation. Currently I have a layer with the X and Y coordinates of electric distribution poles, where each pole ...
3
votes
3answers
753 views

Draw line between points from multiple datasets

I have 2 point datasets and want a tool or script to draw a line between all points in one dataset to all the points in the 2nd dataset. Is it possible? I have tried ESRI "Point Distance" and ...
9
votes
2answers
3k views

Measuring distance in spherical Mercator vs zoned UTM

I've got points in WGS84 lat/long and I'd like to measure "small" (less than say 5km) distances between them. I can use the haversine formula from http://www.movable-type.co.uk/scripts/latlong.html ...
8
votes
2answers
1k views

How do I group near points with GPS positions?

I'm an IT person so I don't know too much about projections and so on, I hope you can help me. I have made an application for Android that collects a GPS position, so I have the latitude and the ...
8
votes
2answers
792 views

Projections appropriate for global analysis that preserve area and that preserve distance (but not necessarily in the same projection)

I am looking for a projection (or a set of projections) that decently preserve distances so that I can buffer every country in the world and have a similar level of minimal distortion for each. I ...
7
votes
3answers
239 views

What's a term for Sea Level Distance which is usable by novice users?

I've been using the term Sea Level Distance to describe the total length of a line string where I ignore the elevation and just calculate the distance from point to point along the ellipsoid and sum ...
6
votes
1answer
655 views

How to measure distance between points based on elevation?

I need to be able to measure distances between points, however the distance need to be calculated in relations to elevation. The points are homes of storytellers from the 19th century and the places ...
6
votes
2answers
1k views

Get shortest distance between two geometries in ArcPy

I'm using ArcPy and using a cursor to step through one polygon feature class. For each of these 'source' polygons, I am creating a SearchCursor to find all polygons in a second feature class that ...
4
votes
1answer
664 views

Correct use of the terms geographic, path, and Euclidean distance

I often use the terms geographic and Euclidean distance interchangeably when referring to the length of the shortest straight-line distance between two points on a map. Is this correct? I use the ...
4
votes
1answer
802 views

How to use/interpret/visualise a distance matrix with unknown coordinates?

How would you go about using a distance matrix where points have no coordinates, i.e. what useful statistics can be made and how to visualise it in some useful way?
3
votes
2answers
362 views

How to calculate the distance of sites to riverways

How do you calculate the distance of about 10 sites scattered across a region to bodies of water (rivers and lakes) using ArcGIS 10.1? I have the lat/lon coordinates of the 10 sites as a point ...
3
votes
2answers
5k views

How to find nearest point for each point in current layer using ArcGIS Desktop?

I have a point layer and want to know the distance of nearest point of current layer for each point in the layer. I found some tools in ArcToolbox about it , but they need two layers for input and ...
2
votes
1answer
479 views

Finding and using data on population density files

I'm attempting to replicate this map for the state of Nevada in QGIS: source: http://www.bostonfed.org/commdev/c&b/2014/spring/map-distance-to-closest-snap-outlet.htm (A SNAP outlet is just a ...
2
votes
1answer
881 views

How to Determine to world map size in pixel given this data?

How to Determine the world map size in pixels given this data? Map size of a particular area say, for example: Makati city, Philippines with bounds: Top-Right: 121.0281, 14.56497 Bottom-Left: ...
1
vote
0answers
263 views

Query all Object within n kilometer Radius with Hibernate Spatial?

I use hibernate spatial attach a geolocation to a car. My card domain class looks like this: import com.vividsolutions.jts.geom.Point class Card { String name Point location } My program is ...
1
vote
0answers
101 views

Using the accCost() function in R: questions regarding the transition layer

I am trying to use the accCost() function from the gdistance package in R. I load my cost raster using the raster()function from the raster package. According to the documentation, I need first to ...
5
votes
2answers
300 views

Way to find minimum value from a group of values - QGIS?

I'm wondering if there is a way to find the minimum value of a group within QGIS? Basically I need to find the minimum distance of each unique value in a table of about 5000 records. I can do the ...
5
votes
2answers
238 views

Calculating average raster to point distances within census tracts

I have some experience using ArcGIS, but mostly with the field calculator in the attribute table/spatial joins, so I apologize if I say something that doesn't make sense. To provide a bit of ...
5
votes
0answers
303 views

Constructing a Voronoi diagram using a complicated travel time metric

I have in my possession four sets of shapefiles: 1. Locations (points), around 1000 2. Roads (lines), each road has a speed attribute 3. Terrain (polygons), each zone also has a speed attribute 4. ...
5
votes
1answer
2k views

Distance Matrix tool in QGIS. How to get result in metric? [closed]

I'm trying to calculate the distance between points in layer with distance matrix tool. And keep getting strange results no matter what. Like this MASTER ------------SLAVE ---------------- DISTANCE ...
4
votes
1answer
45 views

PostGIS point distance from polygon not 0 when on edge

I have a pretty simple problem: SELECT * FROM ST_Distance(ST_GeographyFromText('POLYGON((70 -40,70 -39,71 -39,71 -40,70 -40))'), ST_GeographyFromText('POINT(70.48 -39)'), False) returns ...
4
votes
1answer
528 views

How to measure the distance of multiple points to a line

I have two shapfile in QGIS to which I am trying to find the distances between. I have a shoreline which is a vector line and then I have hundreds of data points in the ocean. What I am trying to find ...
4
votes
3answers
2k views

Comparing two point shapefiles that contain lat/longs and compute distance using ArcGIS Desktop?

I have 2 sets of point shapefiles in ArcGIS Desktop (group A and B), each set has around 1000 entries that contain lat/long. What I want to do is compare Group A against Group B and figure out for ...
4
votes
2answers
867 views

Plugin for average distance from node to polyline in QGIS?

Is there a plugin available that will calculate this? EDIT 1: The red polyline is the average distance of the point to the black polyline. The red polyline is what I want to display. Alternatively, ...
3
votes
3answers
267 views

How to convert points to lines?

I want to convert these points to lines, however they are not sorted sequentially along a line (by ID or FID), i.e. the converted lines zig-zag across the obvious trail of points. How can I join ...
3
votes
1answer
162 views

Proof of part of haversine formula?

I'm trying to study how to find the distance between two points if their latitudes and longitudes are given. I have a question about the proof of part of the haversine formula given at Math Forum. ...
3
votes
2answers
1k views

Calculating the distance between points and multiple lines?

I have a point shapefile of about 100 points and a polyline shapefile of about 200 lines and I am interested in finding the distance between every point and each individual polyline. My polyline ...
3
votes
1answer
1k views

How to draw a polygon with preset length in OpenLayers?

For a project I am working on, I need to be able to put a polygon on a map using OpenLayers, based on a variable point that can be set by a user. The polygon is an isosceles triangle of which two legs ...
3
votes
1answer
943 views

Getting points within a range from a postgres database?

ok so this is query i'm making which returns no result: SELECT building.gid FROM building WHERE ST_Dwithin(building.geom, ST_GeomFromText('POINT(long lat)',4326), 400) If I run this ...