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

learn more… | top users | synonyms

7
votes
2answers
4k views

QGIS calculate distance of point along a line

I have a polyline (movement path) and points recorded along the line. I would like to calculate for each point the distance along the line in Quantum GIS. I hope for a result which will add a new ...
3
votes
2answers
1k views

GeoDjango Order by distance for Model that is linked to User who has a location on their user profile

I need to order my query model by distance, however the point field in question is not on the model class but on the user profile and the i am getting an error when attempting the following. g = ...
1
vote
1answer
1k views

Calculate the distance between two contours

I have two contour polylines (single shapefile) and I would like to calculate the mean, min and max distances between the two lines. Is there a function in ArcMap 10 (ArcInfo license, incl. Spatial ...
5
votes
1answer
1k views

How to find the two furthest points between a group of points?

I have a table with 20000 records and with those columns Shop, longitude, latitude, geom I would like to find a way to find the pair of ths farthest shops between a selection of shops For example we ...
2
votes
3answers
9k views

How to calculate how long an arc second is for a given long/lat?

I am wondering what area is covered by a dataset which is one arc second wide.
4
votes
1answer
918 views

Calculation of average point distances from one another within a polygon grid

I am working with processed LiDAR data of forested areas in ArcMap 10, with various area based statistics extracted for each 30x30m polygon grid-cell in a shapefile. There are approximately 20,000 of ...
1
vote
1answer
2k views

Measuring on OpenLayers map

These days, I am trying to develop web map using openlayers. I copy source code from here Then I changed code to display my data.B ut it does not work, even map is also not showing. In chrome shows "...
2
votes
2answers
3k views

How to get vector feature information (distance and extent ) on OpenLayers

I have basic WMS layer and vector layer in openlayers. Using EditingToolbar i can draw some features as shown below Then I want to get some information (like distance and extent) of drawn features ...
1
vote
1answer
532 views

Calculating distance between two points on map using ITM coordinates?

How to calculate the distance between two point on the map using ITM coords? i have a map with items on it all with ITM coords and i need to return all items in X meters of radius from my location. ...
5
votes
2answers
5k views

How do I get the distance meter value between two geometries in PostGIS?

I have a simple question about calculating distances in PostGIS. I would like to get the distance between two geometries. I am using this sid : 4269 in meters what i am doing now is this : ...
19
votes
2answers
480 views

Precision when working with spatial data in GIS

Is there a basic or introductory study that examines and compares the precision of spatial data when working with varying precison of the data input, like having 1, 2, ... decimal places? with the ...
3
votes
1answer
2k views

WGS point to WGS line segment (great circle) distance

How would I go about resolving this in C#? I have a line segment (great circle distance) defined by two Lon-Lat pairs (call them points A and B). A third point somewhere on the Earth sphere. The ...
7
votes
1answer
1k views

Appropriate distance metric for spatial clustering of geographic coordinates

I have a set of locations in geographic coordinates, and I would like to group the points using hierarchical clustering followed by tree-cutting at various "heights" in order to calculate group-wise ...
3
votes
1answer
192 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 ...
6
votes
1answer
3k 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
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 ...
1
vote
2answers
1k views

QGIS layers no longer overlay when Enable 'on the fly' CRS transformation is on

My QGIS project has two layers - one retrieved from GADM (administrative boundaries of Guinea Bissau) and another one of the villages collected in the field using GPS Decimal Degrees - D.ddddd. If I ...
8
votes
1answer
5k views

Calculating distance to points in QGIS

Is there a way of calculating the distance to the nearest points in QGIS? In ArcGIS there is a function called Euclidean Distance, which can take an input vector or raster, and generate a raster of ...
3
votes
2answers
1k views

Finding the minimum and maximum distance between an observer and a lat/lon bounding box

I have three points in geographic coordinates (latitude, longitude, altitude). One of the points represents an observer, above the Earth. The other two points define a bounding box. I'd like a ...
4
votes
1answer
749 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
2answers
605 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 ...
3
votes
3answers
9k views

Distance between GPS coordinates

Given a database of GPS points, a center GPS location, and a radius R (in meters), how can I find all points in the database that are within a distance of R of the center point? Will the distance iso-...
8
votes
3answers
862 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
876 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?
4
votes
2answers
9k views

How to use Distance Matrix tool in QGIS?

I have a point data set. Now there are cluster of points based on a field. So I take out one such cluster which has points with same field.I want to find distance between all the points in cluster and ...
11
votes
4answers
16k views

How do I calculate the bounding box for given a distance and latitude/longitude

Hi need to be able to calculate a bounding box or circle for a Given WGS84 latitude and WGS84 longitude, and distance but have no Idea where to start! The distance from the start lat Lon would be 10KM ...
9
votes
1answer
9k views

Simple PostGIS ST_Distance query for two points from the same geometry table?

Note: This question was published at Stackoverflow at first. I have a geometry table points_table with SRID 4326 and a few points in it. I need to find a distance between a pair of points (features) ...
3
votes
2answers
1k 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 ...
2
votes
1answer
1k views

How to use Google's Distance matrix on server side?

I am developing a web application wherein i need to find the closest bus-stop from a users location and mark it on a map. I have the list of bus-stops on my server. I am using Google's Distance Matrix ...
3
votes
1answer
1k views

clip linestring by length

Is there a way to clip a linestring based on distance? For example, linestring from a to b is 150 meters. I would like to get the linestring from a to a point that is is 75 meters away from a ...
1
vote
0answers
114 views

Calculate Point C using distance and bearing from points A and B? [duplicate]

Possible Duplicate: Calculating Lat/Lng X miles from point I'm from old school so have not done math for ages. So I need some help to solve this problem, please :) I have two points such as A(...
15
votes
1answer
970 views

Monte Carlo simulation using QGIS and pgRouting on optimal sidewalk construction

I am new to spatial analysis and would appreciate some general direction on a project I am attempting, outlined below (I am starting from scratch). GOAL: To find the best locations to install 2000 ...
4
votes
3answers
6k views

How do I determine the center point of several features in OpenLayers?

I have several polygons being drawn on a map, usually representing a country or province or state. Depending on some chosen data, different regions may be selected, so what I was hoping is that there'...
4
votes
1answer
324 views

Projecting gps data to get length of resulting line shape in ArcMap 10.0

I have gps data in WGS84 geographic coordinates. I will use the gps data to build a line shape in ArcMap 10.0. The data falls in UTM 15N. To get most accurate length of line, should I project the ...
3
votes
2answers
6k 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 ...
4
votes
4answers
3k views

Using a list of geographic locations, and determining the X closest locations to a user-defined location

I've got a list of geographical locations in an Excel spreadsheet. I want users to be able to search for a user-defined location, and then have the X number of closest locations from the list pulled ...
1
vote
1answer
2k views

Radius of Curvature Python/Arc, how access x,y coordinates

I have a polyline in ArcMap 10 and I am able to script the length of the line in Python using this bit of code: #Calculate Radius of Curvature #try: # Import system modules import sys, string, os, ...
5
votes
1answer
522 views

How do I get the upstream distance to all points in a DEM from a single downstream point?

I want to get the upstream distance to all points in a DEM from a single downstream point. The goal is to create a "downstream distance to a point grid". This then would allow me to create "distance" ...
7
votes
2answers
2k 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
3answers
564 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 ...
22
votes
6answers
14k views

How to cluster spatial data in R?

I am very new to R. 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 page and tried clustTool ...
3
votes
1answer
2k views

MS SQL Server's STDistance output differs from Google Earth/Maps straight line distance

I am testing SQL Server STDistance function in the following way: DECLARE @g geography; DECLARE @h geography; SET @g = geography::STGeomFromText('POINT(53.553813 9.99158)', 4326); SET @h = geography:...
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 ...
5
votes
1answer
1k views

Calculating radius / buffer on EPSG 3785 in meters vs buffer in WGS 84 in meters

The goal is working in EPSG 3785 and in particular Google Maps, one wishes to render (on a tile) a circle of a given radius in meters. The rendering is done in pixels. I would guess that one could ...
3
votes
1answer
1k views

Measuring distance between points along a river system

I have a forked river with multiple x,y data points along it and I need to measure the distance between these points when travelling along the river. However the forked part is throwing a wrench into ...
5
votes
2answers
28k views

Looking for a Tool to Calculate Distance Between Points (Between Layers)

I am a college student using ArcEditor 10.0 for a semester project measuring distance to hospitals from census tract centroids. This is my first time using ArcGIS, and I have no formal training. So ...
0
votes
1answer
128 views

ArcGIS WebADF Distance tool

Is there a tool in the WebADF that will let me draw a straight line and calculate the distance between the two points.
3
votes
2answers
2k views

ST_Distance versus ST_Distance_Spheroid?

As my client software uses lat/lon coordinates when communicating with my (spherical mercator) postgis database i decided to ST_Transform every geometry to WGS-84. However i noticed that ST_Distance ...
9
votes
5answers
5k views

Better Distance Measurements in Web Mercator Projection

I am working with an ESRI stack, storing my layers in a sql-spatial-enabled-SDE- geodatabase (Geometry type, Web Mercator-3857). I am building a web mapping application, so by default, the tiles are ...
5
votes
2answers
517 views

PostGIS ST_Distance vs. pgRouting

I am looking to create a city directory web app, and the site will need to be able to calculate distances between two geospatial points (like the distance between the user and a restaurant, or the ...