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
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1answer
220 views

meeting point minimizing travel distance for participants?

The problem is to find the point minimizing the travel distance for around 100 persons in different regions who want to meet in the same place. Travel is by car not by plane. Assuming that I get ...
7
votes
2answers
440 views

projection change to create buffer in QGIS

I am about to become desperate... I like to create buffer around several points - if possible - with a declaration of the size in km of these buffers. Just to show you what I am working with: My ...
4
votes
2answers
286 views

How do I find the average distance within a polygon to a point?

For my purposes, I can assume a homogeneous distribution of points within the polygon. What I want to find is the average distance from points within a polygon to a specified point. I don't know where ...
0
votes
1answer
89 views

How to visualise “distance from amenities”?

I'm interested in calculating for every point the distance to the nearest amenity of each of a certain number of types (train station, supermarket and so on). I think the calculation will be ...
1
vote
1answer
82 views

PostGIS integer loop

PostGIS is very new to me, and I'm having difficulty performing an operation that probably isn't too difficult. I have vector layers each filled with the outline of a landmass through time. I want to ...
2
votes
0answers
102 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. ...
0
votes
1answer
126 views

How to correctly convert data from OSM with osm2po to use it with A* algorithm?

I want to make my A-Star fast, by using heuristics. At the moment it is very slow and even slower than my Dijkstra. I thougt A-Star is in the worst case as fast as Dijkstra. I convert my OSM bounding ...
1
vote
2answers
200 views

find latlngs that are some x distance away from a point to south to north to east to west

I have a latlng i want to find four points with equal distance from this latlangs in all directions east, west, south an north is there any formula . I am trying to build polygons around higways so ...
0
votes
0answers
14 views

how to create several buffer around 1 point with attatched distance information (qGis) [duplicate]

hello guys, I need to know how to create several Buffer (like isochrones) around 1 Point (the distribution center). The buffers should include a distance description. For example the first Buffer ...
4
votes
1answer
88 views

How to calculate average distance from points to points?

I have a point layer of 400,000 voter residencies and a point layer of 500 polling places. I am trying to find the average distance it takes voters to get to their polling location. Distance by road ...
3
votes
3answers
225 views

Why is sum of st_length() of segments 20% too big?

I'm running a query to return the total length of some bike paths, from OpenStreetMap. Compared to the known actual length of these paths, they're all a bit too big - something like 10-30%. I know it ...
1
vote
1answer
240 views

QGis creating shape file of several points out of two Excel sheets

I am about to create a Qgis file on which it should be visible which companies are working together. As source I have got two Excel Tables. Table = Distribution Centers Table = Point of sales I ...
0
votes
0answers
230 views

Bearing Distance to Line tool from dBASE table only draws one line in ArcGIS 10

I am using the Bearing Distance To Line tool to draw geodesic lines to points defined by a bearing and distance. This is an aside, but I will then use the Feature Vertices To Points tool to convert ...
1
vote
0answers
41 views

windows function with points in a mixed (multipoint/point) table

I have a table comprising multipoints (tracks) and points (stops between tracks). there can be several consecutive multipoints. now, i want to merge any points lying very closely to each other ...
1
vote
1answer
574 views

Distance between DB field and Point using PostGIS

I'm using Postgresql 9.0 with PostGIS 2.0 extension. I've got the table and geographic field location: =# SELECT * FROM geography_columns; f_table_catalog | f_table_schema | f_table_name | ...
4
votes
2answers
426 views

ST_Distance is not delivering right results

I want to calculate the distance between lat/lon points. I tried the following queries: Select ST_DISTANCE(ST_GeomFromText('POINT(-73.97923 40.75571)', 4326), ST_GeomFromText('POINT(-73.974509 ...
5
votes
2answers
264 views

How to create a point along a line given a distance from another point

I'm trying to figure out a point(D) on B-C that is a specific distance from A. I really don't have any idea on how to proceed with the ellipsoidal math so I figured I'd ask here. How would I figure ...
8
votes
1answer
209 views

How to automatically reduce polygon size?

I am working with two polygon layers (counties & states) which I will 'intersect' to find which counties are within which states. Due to data inaccuracies I have to change all county polygons and ...
0
votes
1answer
62 views

Point to point distance over specified distance

I need to calculate the distance between neighbouring points which conform to a staggered line. I have two point datasets, one being the baseline and another the monitor. The points typically reside ...
0
votes
2answers
354 views

How to determine average distance from points to line?

I have a polyline road dataset and a study area (polygon) covering the the road dataset. I want to determine the average distance for every given point within the study area to the nearest road. i ...
4
votes
1answer
145 views

How to find Closest Facility (euclidean distance)?

I have some facilities and incidents, and I want to find the closest facility for each incident. I've done it via Network Analyst (with a network dataset) but I'm wondering if you can do it with just ...
3
votes
1answer
42 views

Does IDistanceOP.EucDistanceFull require a projected coordinate system?

I have designed an implementation of ArcObjects' IDistanceOP.EucDistanceFull. It takes its input as a feature class and converts it to a GeoDataset with which EucDistanceFull can work with. It works ...
0
votes
0answers
172 views

how to create Euclidean Distance in QGIS

I'm trying to create distance layer for points in QGIS (similar to Euclidean Distance in ArcGIS). I see the answer you give in the url Calculating distance to points in QGIS I try it using rasterize. ...
0
votes
0answers
22 views

Can I apply the Euclidean Distance tool for a single point feature class? [duplicate]

So, as suggested in my previous question, I tried to perform perform the Euclidean Distance tool for a single point feature class. For som e reason it doesn't work and the error given is ERROR010092: ...
2
votes
1answer
304 views

Create raster distance around a single point feature class

Okay, so I'm relatively new to ArcMap and I'm trying to use the Fuzzy membership for suitability test. I have a single point feature class that I want to use for this analysis. I know that in order to ...
4
votes
1answer
314 views

How to access the road graph plugin in python?

I am developing a few scripts in Python for QGIS 1.8 to automate some geo-tasks and one of them would be to calculate the shortest distance from a hospital to each building in a town. I would like to ...
3
votes
1answer
117 views

Get the total distance from a point to the end of a linestring

I have a list of GPS coordinates that make up a bus route: busRoute = [(x1, y1), (x2, y2), ... (xn, yn)] I also have a point that may not be exactly on that route (due to GPS error): ...
1
vote
1answer
124 views

What is the preferable value for setting tolerance for selecting a feature

I know it's really a basic question. But I am really confused about this. For selecting a point feature by mouse click, we need to set a tolerance value to create the envelope. And here is the problem ...
1
vote
1answer
745 views

postgis distance calculation between points with lat, long coordinates

Team, I am new to postgis, but a postgres user for quite a while. I would like to compare the geospatial capabilities between postgresql and mongodb. I have the lat.lon, zip code of US locations; ...
3
votes
1answer
210 views

What formula does SQL Server 2008 use in STDistance?

I am analyzing the accuracy of the STDistance function for geographical objects in SQL Server 2008, in order to understand its behaviour better I need to find the underlying formula. Does anyone ...
13
votes
2answers
1k 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 ...
0
votes
1answer
54 views

error in estimate distance?

i do some experiment place two sensor node between them 4 meter as distance. then i get these GPS information: node1: Latitude: 32, 33.255 , Longitude: 36, 0.6632 node2: Latitude: 32, 33.228 , ...
3
votes
1answer
284 views

How can I make a Postgres/PostGIS ST_Distance_sphere query more efficient?

Within Postgres/PostGIS I have written an 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 ...
1
vote
1answer
300 views

Accurate and fast nearest neighbour, which distance function should I use and how to it speed up? [duplicate]

I am solving the following problem: I have a map with many points in it and I need to find the nearest point to given location. Each point carries information about it's latitude and longitude. This ...
3
votes
1answer
443 views

How to create points at shortest euclidean distance to other points?

So, I have a lot of points, and I need to site three new points so they will be at the shortest euclidean distance between all of the other points. In other words, these three new points that I need ...
3
votes
1answer
393 views

Pivot a polyline at vertex or distance using ArcObjects C#

I hope you can help me with that one. I'm using ArcObjects with C# trying to rotate only one part of a polyline at a vertex or distance along the polyline. The polyline is zAware and has values at ...
0
votes
0answers
124 views

Offset a Polygon defined in Lat Lng points by a given distance of miles or km

I am trying apply a positive offset/buffer (enlarge a shape equally from the borders) to a polygon that is made up of a series of latitude/longitude coordinates by a distance that is defined in either ...
2
votes
1answer
286 views

Find projection of a point to a line

I have a segment defined by 2 LatLon points(A and B) and a third LatLon point (C). I need an alghorithm, formulae, or some code to find the projection point of C on the segment AB (call this point D) ...
0
votes
0answers
20 views

Distance from rivers-Zonal Statistics [duplicate]

I am using arcgis 10.1 I am trying to calculate euclidean distance from each feature using this large rivers shapefile http://www.arcgis.com/home/item.html?id=44e8358cf83a4b43bc863646cd695945 . And ...
0
votes
1answer
106 views

How to set the length of a line using openlayers

I'm trying edit a polygon by changing the length of some lines by code. Found this method to calculate based on the bearing. But I didn't find anything on how to calculate the bearing, before I start ...
2
votes
1answer
257 views

Correct coordinate systems, but trustworthy distance between points?

I have limited GIS experience with projections and I have some questions about trying to accurately display point data from two different sources in ArcGIS 10.1 in order to do a proximity analysis. ...
9
votes
1answer
218 views

Measuring distances between simultaneous points

I am working with GPS data and so I have UTM's with DATE/Time information. I have 2 groups of species (moose and wolves). I want to join the information from moose to wolves that match in time. So, ...
1
vote
1answer
443 views

Get the distance from a point on a polyline to polyline's from point

I have a polyline and a point on the polyline. I need to find the distance from the from point of the polyline to that point. ICurve.QueryPoint method does the opposite thing. It gives a point ...
2
votes
1answer
417 views

Trilateration 3D - Vincenty's Formula

with reference to Trilateration using 3 latitude and longitude points, and 3 distances. The accepted answer was votes as shown in wikipedia at: http://en.wikipedia.org/wiki/Trilateration in ...
4
votes
1answer
170 views

Distance from waterways

I have an sdc file with water bodies, i.e. oceans-rivers-lakes. I want to combine it with a shapefile with the boundaries of countries all over the world and produce two measures: 1) The average ...
0
votes
2answers
218 views

Road network Analysis

I have a Road layer and Point features of some Bus stops from the same area.I want find the Road distance between the Bus stop.Please help me find it. I have QGIS,ArcGIS,and FME. Thanks, RKM
1
vote
0answers
296 views

Get the distance between 2 WGS84 GEOSGeometries

I currently want to check if 2 given GEOSGeometry objects of type Point are within 100m of each other. (length flexible) Looking at previous asked questions on this topic, most of the answers were ...
3
votes
2answers
629 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 ...
6
votes
4answers
445 views

How to calculate the “depth” of a linestring using postgis

I have linestring features, which look like bent linestrings, hemicycles or convex or concave linestrings. In the moment I can select the distance between the startpoint and endpoint of each feature. ...
3
votes
2answers
383 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 ...