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

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3
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1answer
2k 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 ...
6
votes
1answer
4k views

OpenLayers measure tool - instant measurement

I need to use measure tool to measure distances (instant measurement!) in my application. Instant measurement example can be found here. But the main problem is that when I use instant measurement ...
3
votes
1answer
1k 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 ...
4
votes
1answer
336 views

Tunnel distance approximation

Having two points (longitude, latitude) on earth, if I am sure their distance is under 100 km; how much error will I have using tunnel distance approximation? (Defined at here) Note: Currently I am ...
8
votes
2answers
271 views

Which SRS to use for global distance queries?

I have a database with a lot of points in WGS84. Now I am building an cache that performs NN and points in range queries using a KDtree. The point [sic] is that the search radius will be provided in ...
1
vote
1answer
371 views

Calulate distance between two points [closed]

If I have two coordinate points of (lat, lon), how would I calculate the distance between the two?
5
votes
3answers
3k views

Dissolving polygons by attribute within certain distance using ArcGIS Desktop?

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 ...
3
votes
2answers
240 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 ...
3
votes
0answers
440 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 ...
3
votes
3answers
2k views

How to measure minimum distance between objects in two layers using arcpy?

I am working on an alien species analysis looking at the spread of a species from the mainland to islands in an archipelago. I am doing the analysis using arcpy and I have succeeded in isolating risk ...
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 ...
1
vote
2answers
434 views

Recovering Latitude and Longitude from Albers to Compute Distance

I have a shapefile of U.S. counties in USA Contiguous Albers Equal Area Conic. I want to do distance calculations. For example, distances from one county to another. I do not know how to interpret ...
1
vote
1answer
53 views

Obtaining coordinates when computing distance of a polygon to a line

I have a shapefile of a county. I am interested in computing its distance to a line, which I've been doing using Near. I want to know the coordinates on the line that produces the minimum distance. ...
1
vote
1answer
251 views

Distance of many polygons to a segmented line

I have a shapefile of U.S. counties. I also have a line segment. I want to compute the distance of each county to the line. I have also divided the line segment into 10 equal segments. I want to ...
3
votes
0answers
914 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, ...
6
votes
3answers
724 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) ...
1
vote
1answer
1k views

USA Contiguous Albers Equal Area Conic

How do you convert from USA Contiguous Albers Equal Area Conic to meters? Or, to latitude and longitude? I am using ArcGIS 10.1, and within it, ArcMap. The shapefile I have reports the coordinates ...
2
votes
1answer
7k views

Getting shortest distances between features on separate polygon layers using ArcGIS Desktop?

I have a county-level map for the state of North Carolina, U.S. I would like to compute the shortest distance of each county to any point along the border of Georgia. How would this be done? ...
2
votes
1answer
668 views

How to find the closest Edge from a Line

Currently I'm working on a basic 3D model viewer in MATLAB, which can import .OBJ files (modeled in e.g. Blender). The purpose of this viewer is to test different subdivision schemes (like Catmull-...
0
votes
1answer
125 views

If the Earth was flat, what unit of measurement would distances between geographic points be represented as?

A whole lot of abstraction- given two longitude/latitude points given from a GPS, I'm using the Pythagorean distance formula to find the distance between them. What unit of length would the distance ...
3
votes
1answer
841 views

How to make a minimal distance matrix for polygons using QGIS?

I have a set of polygons and I want to find minimal distances between the edge of each pair of them. It's similar task as in this question: How to find the minimum edge to edge distance of polygons? ...
1
vote
1answer
369 views

PgRouting Driving Distance crashing postgis server

I haven't used PgRouting much so I'm a little in the dark here. However, I am attempting a driving distance calculation like the one described by Underdark here. My SQL is identical, I have a ...
8
votes
5answers
6k 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 ...
5
votes
2answers
12k views

How to calculate new point coordinates from distance and angle using ArcGIS SDK for iOS?

I want to calculate the coordinates of a new point. What I have: The source point coordinates, the distance (meters) and the angle For example: I want to create a point within 100 meters and 45 ...
10
votes
3answers
40k views

Find points within a distance using MySQL

I have a mySQL table with user name, latitude and longitude of the user. I would like to get a list of user who are inside the circle or square of a given latitude and longitude with given distance. ...
1
vote
0answers
131 views

Is there a ModestMaps or other flex library for finding the distance between 2 lat/lon coordinates?

I'm using ModestMaps in my Adobe Flex application. Is there a flex library method to calculate the distance between two of my lat/lon coordinates, or am I stuck coding the Haversine by hand? I've ...
2
votes
1answer
102 views

How to Improve a Distance Model

I am working on a distance model that creates distance rings around a given point and assigns those rings a probability. The point is in the center of a 25 x 25 km area, and the model fails to assign ...
1
vote
0answers
30 views

Translate geographical coordinate [duplicate]

Possible Duplicate: Calculating Lat/Lng X miles from point I would like to know how could I translate a geographical coordinate to an specific distance. So for example let's suppose I'm facing ...
0
votes
0answers
797 views

Implementing custom (Vincenty/Haversine formula) functions for MySQL vs Using PostGIS?

I currently am using MySQL for all of my relational data. I have hit a crossroads with geo calculations. Since, MySQL does not have good support for spatial functions, I am contemplating on using ...
4
votes
1answer
5k views

Distance calculation : Integrating incremental gps data

I am trying to build a GPS based odometer based on android. Currently , I am calculating incremental distance changes very frequently ( < 5 meter movement). The distance calculation in android is ...
3
votes
1answer
422 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 ...
2
votes
1answer
1k views

MySQL GeoSpatial function for ST_Distance_Spheroid? Metric used in return Type of GLength?

Is there a ST_Distance_Sphere, ST_Distance_Spheroid equivalent function in MySQL's GeoSpatial Support? If not, any way to emulate this? What is the metric used in return type of GLength (...
6
votes
2answers
610 views

how to find the point in a country furthest from a boundary

i'm trying to find the point in south africa furthest from the sea or a landward boundary. my method thus far: i obtained a first guess at the centre of the inscribed circle and the three segments ...
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 ...
10
votes
2answers
2k views

Calculate Distance between a Polygon and a Point Along a Path

I am very new to ArcGis and am trying to figure out how to do this. Basically, this is what I am trying to do: I have a map of Canada and in it I have polygons representing areas (each about the ...
4
votes
4answers
13k 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 ...
8
votes
2answers
1k 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 ...
4
votes
2answers
2k views

tool to find the routing distance between two latitude/longitude points using OSM data

I need a tool to find the distance between two points whose longitude and latitude are given. I am making an application so it will require bulk queries, so i cannot use google maps distance matrix ...
3
votes
1answer
278 views

How to calculate maximum distance to an interpolated value along a contour in QGIS?

I'm planning to enter concentrations of groundwater contaminants collected from well locations into QGIS and then use interpolation functions to create contours of the groundwater plume. Can QGIS ...
1
vote
0answers
173 views

How to create a dynamic distance calculator for selected line feature classes?

My situation: I am relatively new to GIS so forgive me if this is a stupid question. I am working on a project at a park that I am interning at where the goal is to create a single feature with ...
3
votes
2answers
2k views

How to find a point on given line that its distance from another point is given also?

I have this input: (lat1,lon1), (lat2,lon2) - Two coordinates that create the line (lat0, lat0) - Point on this line d - distance I want to find a point (lat, lon), where (lat, lon) is on the ...
2
votes
0answers
2k views

Calculate cumulative distance between points in a dataset in ArcGIS 9.3 ArcInfo

I am working with several point datasets that I have received, with the points representing xy locations with elevation data for several levees in south Louisiana. I would like to be able to calculate ...
5
votes
1answer
754 views

How to compute the distance between centroids and polygons?

Suppose I have an Excel spreadsheet with the latitude and longitude of the centroid of every county in the U.S. I want to know the shortest distance from each county to any part of Oklahoma (...
4
votes
1answer
863 views

PostGIS - table with 3d points with fast ordering by distance

I am pretty new to PostGIS and I am trying to solve the following problem. I need a table with 3D points (x,y,z) that will contain around 1-10million points. I want to be able to efficiently ask the ...
3
votes
1answer
160 views

Method to compute and visualize the closest set of facilities from OSM data

I want to use OSM to extract a set of facilities e.g. school, park, hospital inside a given region. from that, transform the area in grid and for each cell in a grid compute its score mixing the ...
18
votes
6answers
26k 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 ...
4
votes
1answer
3k views

Distances in {Plate Carrée projection - EPSG:4326 - WGS84}

So, "4326 is just the EPSG identifier of WGS84" [3], indeed http://spatialreference.org/ref/epsg/4326/html/ says it is a GEOGraphic Coordinate System: GEOGCS["WGS 84", DATUM["WGS_1984", ...
2
votes
1answer
3k views

distanceTo is giving wrong result in OpenLayers?

Hi i am using distanceTo from OpenLayers to calculate the distance between two locations these are map details Geographic = new OpenLayers.Projection("EPSG:4326"); Mercator = new ...
39
votes
2answers
5k views

How accurate is approximating the Earth as a sphere?

What level of error do I encounter when approximating the earth as a sphere? Specifically, when dealing with the location of points and, for example, the great circle distances between them. Are ...
7
votes
3answers
6k views

Splitting lines automatically at specific distances using ArcGIS Desktop?

I have a set of polylines which I need to split at varying distances from their starting points. In general, I'm looking for a something similar to the SPLIT function within the editor tool. There ...