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

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2
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0answers
51 views

Measure distance between points along a line in QGIS

I have a road network and different points connected to the roads. I would like to measure the distance between several points along the roads. Basically I want to do the same like the road graph ...
1
vote
0answers
22 views

Computing intersection of distance circles around fixed points [duplicate]

(to simplify calculations, I assume a spherical earth. All distances are assumed measured "as the crow flies") Suppose we have the lon/lat coordinates for two points (p_1,p_2) less than Nkm apart. ...
14
votes
7answers
8k views

Which tools and methods can be used to create isochrones?

I'd like to get an idea for what's involved in creating isochrones for a series of sites, with a reasonable degree of accuracy to the estimates. A general outline would be great, though my scenario ...
1
vote
0answers
36 views

How analyze reliability of position of new point based on point data

I am working on filter for biogeographical data. It is based on citizen science principle. People put new point data to database and I want add information about "reliability" or probability (maybe ...
8
votes
5answers
5k views

Geodjango- get the distance between 2 points

What I want to do is quite simple, I have 2 locations defined by gps coords, lat / long like returned by google maps: http://gmaps-samples.googlecode.com/svn/trunk/geocoder/singlegeocode.html I need ...
17
votes
3answers
4k 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 ...
11
votes
1answer
128 views

How big does a circular geofence need to be for the curvature of the earth to matter? [duplicate]

I'm working on adding geofences to a mobile application. I know the proper way of calculating distance between two points on a sphere is using the great-circle or Haversine formula. I don't know if ...
2
votes
2answers
111 views

PostGIS get the distance between two points over a linestring

I have a linestring: LINESTRING(-1.3326397 50.9174932,-1.3319842 50.9166939) and I select two points that lay on that linestring. I would like to get the distance between these two points (in ...
1
vote
1answer
63 views

Get distances between boundaries from an SpatialPolygon and raster pixels

I am trying to calculate the distance from several pixels of a raster to a boundary of some polygons in R as it is showed in the image. I have two problems: How to correctly define a boundary from ...
0
votes
1answer
187 views

calculate distance between points crossing the antimeridian

How can I calculate the distance between two points (lon/lat) if any of the points exceeds the antimeridian (+-180 longitude)? Im using the distVincentyEllipsoid {geosphere} to calculate the shortest ...
2
votes
1answer
51 views

Hive GIS ST_GeodesicLengthWGS84 not returning expected distance

I am trying to find the distance between two points (in meters and not degrees) using GIS Tools for Hadoop by ESRI. The ST_Length provides distance in degrees and hence I used the ...
1
vote
1answer
52 views

cells w/in search window GRASS GIS

I am trying to find all cells that are a certain distance and within a certain window from a cell of interest. For example: I want all cells in a distance of 10m within a search window of 10 - 40 ...
2
votes
1answer
200 views

Measure distance between vertices of polylines in QGIS for Desktop

I have this dataset of coordinates of electric lines in the form of vector polylines as shown in the image below, and I need to measure the distance between the first and last vertex of each line and ...
3
votes
1answer
56 views

How to measure the Speed between two Waypoints?

I'm totally new to QGIS or any GIS. I need to analyze a lot of Waypoints to get the average speed of the people walking between them. (It's for analyzing an experiment I made) therefore I neet do ...
2
votes
0answers
24 views

OpenLayers measurment path in 31700 projection

I have this code who works great for distance measurment on 900913 projection with 4326 display projection (bing maps + layer WMS): measureDistanceControl = new OpenLayers.Control.Measure( ...
1
vote
0answers
50 views

Calculate distance from a point to the border of polygon (US state)

I have a point, and I want to know if it is nearer than 100 miles from some US State border (California for example). I assume that I would need to use this: US Regions State Boundaries. But if I ...
3
votes
2answers
167 views

Measure distances between specific features in QGIS for Desktop

I'm completely new using PyQGIS and developing plugins. Currently I have a layer with the X and Y coordinates of electric distribution poles, where each pole is a feature. What I need to do is ...
1
vote
0answers
27 views

Incorrect results returning from st_distance_spheroid query

Given a routable network table constructed by completing the guide at http://anitagraser.com/2011/02/07/a-beginners-guide-to-pgrouting/, how can I get an accurate list of all roads that are within a ...
45
votes
6answers
15k views

Why is the 'straight line' path across continent so curved?

This is the result of mapping the straight line path from a point in US to Poland using Distance Measurement Tool. Also, planes from Asia to US would travel almost over North Pole. Why is the path ...
2
votes
2answers
42 views

How many query points fall within distance X to a set of LineString

I have a set of 10 query points and I want to know how many of them are with distance within at most 4 meters of any LineString in a given table. Note that if a point is within 4 meter distance to ...
5
votes
5answers
17k views

For every point, distance to nearest polygon of type X?

In ArcGIS Desktop, can you calculate as an attribute value the distance to the nearest polygon of type X? Assume we have a point layer of wildlife observations and we want to know how far each of ...
2
votes
0answers
20 views

Using “snap pour point” to find a watershed of specific area starting from a point

I am trying to find everything downhill of a certain point in order to create a watershed of a specific area. For example, say I have a point at (x,y), and I'm interested in creating a watershed ...
2
votes
1answer
35 views

Calculating distance between points from table of UIDs [ArcMap]

I have a .dbf file containing pairs of point feature Unique Identifiers (UIDs), and need to calculate the straight-line distance between each of these pairs. The XY coordinates of the individual ...
0
votes
0answers
22 views

EPSG:4978 or others for Distance

Usually when I have been calculating distances I project to the system which has the tightest crop around my points e.g. for the UK #http://epsg.io/27700-5339 (accuracy: 1.0m) uk = '+proj=tmerc ...
1
vote
0answers
24 views

Build network based on shortest distance between points

Is there a way to build a network based on the shortest distances between each point of a point layer. I have occurrence data from species (as points) and want to estimate whether there are one or ...
0
votes
0answers
15 views

How to select within a distance using QGIS [duplicate]

With QGIS 2.12.3, I have two projected EPSG:2927 point shapefiles, A and B. I would like to create a selection of A points that are within 100 meters of any B point. This is easy in Arc, using the ...
3
votes
0answers
53 views

How to calculate best path between 2 points from a DEM in Qgis?

I'm analyzing the roads and paths of a region by calculating how effective the communication is in the region. First I calculated the shortest paths between the points using the actual road map. Now ...
3
votes
2answers
44 views

Calculating areas outside a point

I have a university assignment that requires me to find an optimum location for a land fill site. There are various parameters I need to map. I have managed to map all the ones within a distance of ...
4
votes
1answer
250 views

Calculating Distances between coordinates

I have 75 coordinates in WGS84 that I brought in from an Excel table. They are now on my imagery basemap spanning across about a half mile on either side of a dirt road in Prescott National Forest in ...
6
votes
1answer
104 views

How to group 10k points into closest pairs?

I was first faced with a problem of grouping 1000 pairs into unique pairs to minimise the total distance - since this was a small number I solved it using linear optimisation: Part 1 - Basic/Naive ...
3
votes
1answer
46 views

Vincenty or (Project + Euclidean) for accurate distances

I posted a similar question on stackoverflow, however was directed here for more help. If my main goal was to calculate distances such that my error was minimised to the nearest metre assuming that ...
1
vote
1answer
32 views

QGIS: Distance Matrix tool omitting some points in output table. (qGIS 2.10.1-Pisa)

I have used the Analysis Tools -> Distance matrix to merge two datasets by the closest points. But in my output csv file, some of my points are left out. In the original datasets, none of these points ...
6
votes
3answers
669 views

Network distance computations using GRASS

I'm an ArcGIS user who's interested in learning to use GRASS. Can anyone point out resources that will help me in learning how to obtain network distances between (1) residential locations (points) ...
2
votes
1answer
436 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).
1
vote
2answers
238 views

Finding point on road network at specifc distance from a specific point

I have road network in a geodatabase. At a certain junction in network (Point A), I want to figure out Point B which is X kilometers away from Point A in certain direction. Summary: Point A: fixed ...
2
votes
0answers
59 views

Why this pyqgis code cause crash dump in QGIS?

In ArcGIS there is gp.EucDirection to calculate Euclidean allocation, distance, and direction around a point, Is there equivalent function in pyqgis or gdal? I wrote a script with help of gene and ...
0
votes
1answer
83 views

PostGIS Get the POINT that is x meters away from a fixed point on the route (LINESTRING)

We have a route network stored in the routes table (LINESTRINGs). Basically every sedment (between two vertexes) is inserted as a separate row in this table. Among that we have a locations table ...
1
vote
1answer
59 views

GeoDjango - save two Point fields, one for geography and one for geometry

Most of the explanations I've read for geography and geometry seem to suggest that one must only use either geometry or geography, and that the only way to use both is to cast/convert between one and ...
4
votes
2answers
603 views

Distance Calculation Output Does Not Identify Input Points?

I'm using ArcMap 10 to do distance calculations between a large set of points, using the point distance calculator. The output table generated gives me distances correctly, but the output categories ...
1
vote
1answer
57 views

Finding distance to closest road (polygon to line) in ArcGIS for Desktop?

For my project I need to find the distance to the nearest road from forest polygons. I'm trying to do a weighted overlay analysis (eventually) for a habitat selection project so I think I need to end ...
1
vote
2answers
239 views

Calculate the distance between two coordinates (WGS84) in ETRS89

I have an Excel-file with coordinates (WGS84). From these coordinates I create a line (shp) and transform it (ETRS89). After the transformation I calculate the distance from point to point. I do this ...
0
votes
1answer
53 views

Perpendicular Distance Markers on Polyline in MapInfo?

I have added chainage to a creek polyline in MapInfo v11.0.3 using the 1999 version of "Distance Marker" by Meridian. It looks poor as it does not have the functionality to create the markers ...
0
votes
0answers
43 views

How to create a shapefile from Excel file including coordinates of points and distances between them in ArcGIS?

I wanted to use network analyst in ArcGIS and I have coordinates of points in the network. However, I could not find a shapefile including road information between these points so far (length of links ...
2
votes
1answer
54 views

Getting point from known points to specific distance of polyline using ArcObjects?

I want to know the coordinates of a polyline from specific point and distance. I have attached image to clear the specification. say, I have a points B(2,3). I want to know the coordinates of A and C ...
3
votes
1answer
190 views

Finding distance within which set percentage of features fall using ArcGIS Desktop?

Is there a tool that tells how many features there are within a set distance in ArcView? asked about finding the number of features within a certain distance of another feature in ArcView. I have ...
0
votes
0answers
17 views

Scaling distance by area

For each administrative unit, I calculate the median distance between businesses. However, for larger unit, this distance is naturally bigger (and does not paints a fair picture of, say, the effort by ...
3
votes
3answers
696 views

Why is geography faster than geometry for distance calculations?

Intuitively, I thought geometry would be faster than geography distance calculations, but this says otherwise: ...
6
votes
1answer
612 views

How can I make a PostGIS ST_Distance_sphere query more efficient?

Within PostgreSQL/PostGIS I have written a SQL query to get the closest distance for each element within a point coordinate table from a polyline table. The query comes back and works correctly, but ...
2
votes
1answer
111 views

GeoDjango, distance filter based on database column

I have a geodjango model with fields coverage = 10 * 1609.344 reference_point = Point(-72,45) #or some other lat lng class ServiceArea (geo_models.Model): center = ...
1
vote
1answer
36 views

Calculate point location with direction and range

I have a latitude and longitude coordinate pair and I want to find another point location (returning lat and long) but only have the angle/direction and distance from the first point. How can I find ...