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

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1answer
77 views

Shortest path to nearest… something

I have a list of addresses and a map including train stations, schools etc., and I would like to calculate the shortest distance from each address to the nearest train station, school etc. I'm aware ...
3
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1answer
216 views

finding a location on a line using a point and a relative distance with arcgis js api

The problem I'm trying to solve is to find a point on a line given another point on the same line and a distance from the same point. I've been looking on the various RouteTask examples but they ...
3
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2answers
249 views

How to calculate distances between addresses and cities and coast line?

I am totally new to GIS, and so I apologize if my question is not clear enough. My basic problem is the following: I have about 160,000 Danish addresses with longitude and latitude for each address. ...
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1answer
482 views

Measuring Distance from Point to Point Along a Path in ArcMap

I am looking at a village and want to find the distance from each house (point) to the pagoda (point). However, I want the distance to be measured along a path (which I digitized as a polyline) and ...
5
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3answers
137 views

What is the precise distance from equator to pole according to WGS84?

For calculating areas of polygons by means of projecting to a cylindrical equal area projection I came across the following discrepancy: I ended up with a different distance, off by more than 5km, ...
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27 views

Bounding Boxes around nearby points [duplicate]

I've got a table with 200.000 points. My aim is to draw bounding boxes around points where this point have the same name and that are in a maximum distance of 500 meters to each other. I guess I can ...
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2answers
128 views

Distance between latlongs varies in different projection systems?

I have shapefiles with correct projections. The SRS is EPSG 32735 (WGS 1984 UTM 35S) Now, I have these two coordinates from this projection system: (31.3751,-23.4388) and (31.3779,-23.4355). ...
8
votes
3answers
576 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 ...
6
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2answers
257 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 ...
2
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2answers
241 views

Finding points along a path

I am unsure of the best approach to this problem. I can think of some ways of doing it which I will list below but I am looking for the best and most efficient way of doing this. Problem Given a ...
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1answer
162 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 ...
4
votes
1answer
290 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 ...
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0answers
75 views

Sort a collection of points based on proximity using pythagorean (2D) distance

I would like to present a user with a list of points, sorted by proximity to the user's location. Is there any problem with using the pythagorean formula to calculate the two dimensional distance ...
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0answers
108 views

How to create a buffer around a point that takes terrain elevation in account?

In QGIS, I am creating a few different buffer around points to simulate walking distances. For example, 10 minutes walk about 800m at 5km/h. Using population density, I then clip a population layer ...
1
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0answers
142 views

Calculate Distance Matrix for ALL possible combinations in the dataset in QGIS

I have a Vector Layer that is created out of a MySQL database and has the relevant points stored in WGS84 format. The import works well, however, when I try to calculate a distance matrix between all ...
5
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3answers
1k views

Dissolving polygons by attribute and in a certain distance (ArcGIS)

in a FeatureClass I have a lot of polygons which contain attributes of different landuse-types. Now I am trying to dissolve those polygons of the same landuse-type, but only if the distance between ...
2
votes
1answer
91 views

Calculating point proximity in ArcMap 10.1

I have a geocoded point file which (theoretically) contains one point for every zip code in the U.S. I want to create a smaller list of zip codes from this file. The list should include only those zip ...
9
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3answers
6k views

How to generate random locations nearby my location?

I am trying to create random locations nearby my location. What i want is to create random latitude/longitude pairs inside a 200 meters circle surrounding my location. This is the formula i came up ...
3
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1answer
311 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) ...
3
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0answers
249 views

How to calculate the distance to multiple locations from each cell of my raster?

I'm working with Arcgis 10.1 and Python 2.7.2 How can I calculate the distance to multiple locations from each cell of my raster? I tried euclidean distance but it only provides the distance to ...
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0answers
71 views

What is default unit of st_length in pgrouting for osm shapefiles?

I am using st_length to find the distance between two nodes on a way. What is the default unit of the distance returned. I am using data from openstreetmap shapefiles
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1answer
99 views

Converting NEAR results to Meters/Kilometers?

I am having trouble figuring out how to convert the units from the results of my NEAR calculations. I want to convert them to meters or kilometers, but cannot figure out how to do so... ...
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2answers
249 views

minimum distance from the shore (how to retrieve the “shore vertices”)

I am student of Statistics, this is my first time using GIS., I am sorry for the stupidity of the question but I browsed online and could not find a satisfactory answer. I have some spatial data in ...
4
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2answers
355 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 ...
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6answers
3k views

What tools in Python are available for doing great circle distance + line creation?

I need to use Python to create a great circle distance -- both a number, and preferably some kind of 'curve' that I can use to draw in a client-side map. I don't care about the format of the curve -- ...
2
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1answer
66 views

How to compute the distance from the beginning of a line for every points using postgis

I have a line, for which I need to know, for every point that compose it, what is the distance from the beginning. The data is stored in PostGis 2.0 For example, for the line with the point a, b, c, ...
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0answers
93 views

Can QGIS Measure Line tool compute correct geodetic distance?

As I understood, this tool normally shows distance in the project CRS units, not the geodetic meters (despite it actually says the distance is in meters). However, now I read (Section III, 4 - ...
2
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0answers
197 views

Specifying a bounding rectangle using Google's S2 package for spherical geometry [duplicate]

This is my first post on GIS, I hope it is not too trivial a question. I work on a project on Google AppEngine, which is backed by a NoSQL datastore. This makes a proximity filter different from ...
2
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1answer
77 views

Where would a perfectly vertical vertical tunnel through the earth come out?

I am a programmer. I have a point P1 (lat,lon) given by GPS (WGS84) and I want to know the location of a point P2 if I make a straight line from P1 to the other side of the earth. I have read some ...
4
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1answer
256 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
695 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 ...
3
votes
2answers
181 views

Converting lat lon into co-ordinates (in ft of m)

I have a set of latitude and longitude of a series of points which specific the trajectory of a vehicle. If I consider the first point as the origin (0,0), is it possible to convert the trajectory ...
0
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1answer
100 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
85 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
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0answers
138 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. ...
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2answers
220 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 ...
4
votes
1answer
878 views

How to generate a point distance matrix using shortest network distance?

My problem is as follows. To start with, I have the following spatial datasets: A road network; 13,000 odd point locations representing populated localities (ie places where people live); Service ...
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1answer
267 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 ...
4
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1answer
99 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
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0answers
234 views

calculate total Miles in a polygon using Google Map

I have an application that allows the users to create any custom polygon layer on top of google maps, i am interested to know if their is a way to select the road layer in this polygon and then ...
0
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0answers
297 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
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0answers
46 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 ...
3
votes
1answer
225 views

Python - OGR: Distance different than in ArcGIS

I want to determine the shortest distance between a point and a line. I use the following Python script to do so. If I compare the result of the script with the result of ArcMap's Near Analysis, I get ...
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1answer
788 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
495 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 ...
3
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0answers
596 views

Performing a Multicriteria Analysis Using Distance Along a Road Network

There is the possibility that I will be working on a project which will look at thousands of properties in a region and measure their accessibility to different services (schools, parks, hospitals, ...
3
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2answers
4k views

Calculating the minimum distance between points and polygons in QGIS

I have two vector layers: one point and one polygon and I want to calculate the minimum distance of each point from the polygons (ie the distance from the closest point of the closest polygon). Is ...
5
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2answers
293 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 ...
5
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1answer
2k views

How do I perform a proximity search with Postgis?

OK, so I downloaded the Geonames database (cities1000) and wrote a small Ruby program to import them into my table (geo_cities). I then added geography column called geog. So after all of that, I ...
8
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1answer
248 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 ...