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
votes
1answer
928 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
113 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 ...
14
votes
1answer
811 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
4k 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 ...
4
votes
1answer
303 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 ...
2
votes
1answer
3k views

How to find nearest point for each point in current layer?

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
2k 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
1k 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
405 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" ...
6
votes
2answers
883 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
501 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 ...
16
votes
5answers
7k views

How to cluster spatial data in R?

I am very new to R, so please bear with me : > 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 ...
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 = ...
7
votes
3answers
233 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
917 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 ...
4
votes
2answers
14k 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
115 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
4k 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
456 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 ...
5
votes
2answers
3k views

java vividsolutions jts wgs-84 distance to meters

my (java) project uses com.vividsolutions.jts.geom, which provides a distance function. After some googling I finally found that the return value from this function is in central angle degrees, when ...
3
votes
1answer
874 views

Distance between points and polygons in QGIS / PostGIS

I need to work out the distance between a table of polygons and a table of points. The table of polygons has different site boundaries, and the point table has points relating to each of the site ...
2
votes
2answers
870 views

MySQL Query to fetch all cities and POI's near the route

I'm implementing alghorithm to search POI near the route (array of Lat, Long points). My problem is that I don't know how to calculate distance beetween line segment and POI. Look at picture that I ...
2
votes
1answer
1k views

Using a geodjango PointField with geography=True, my distance calculations are wrong

Here's my model: class ExchangeArea(models.Model): """ An Exchange Service Area, calculated from a phone exchange and surrounding census tracts. """ coordinates = ...
10
votes
3answers
1k views

How can I find the most remote spot in Eastern United States?

I have this hunch that I could travel no more than 50 miles from the most remote spot in the Eastern United States (east of the Mississippi River), in the direction of the nearest road, and find a ...
2
votes
1answer
597 views

How do I query for all polygons within a distance from a point?

Call me stupid, but somehow I couldn't figure out how to do the following. I've got a testing shapefile with 18 features, which I successfully imported into GeoDjango (1.3, running on Spatialite). As ...
6
votes
2answers
497 views

Calculate stop times/distances of transport lines - tools and procedure?

I need to calculate stop times of bus lines (extrapolation) I have: Shape file with all stops shape file with control points where bus time was taken Shape file with all bus routes csv file with ...
5
votes
1answer
1k 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 ...
6
votes
1answer
2k views

Calculate distances between series of points in postgis

I have a postgres/postgis table containing a series of sequential points. I want to add a new column to the table which contains the distance between each point and the first one, and so forth until ...
2
votes
1answer
1k views

Find distance from a point to linestring

I have table (shapetable) with my coastline shape file loaded. I have another table (pointtable) with lat long points. Wondering how would i go about writing a sql query to find the distance between ...
4
votes
2answers
324 views

Total newbie. Creating map from aerial photo of golf course in QGIS

I have a aerial photo in tif with a tfw file of the golf course that I work at. I would like to create vector data of different features on the course such as greens fairways tees, etc. to calculate ...
9
votes
4answers
3k views

Connecting line features and determining the length of the longest line

I have a line feature (see image) representing a river that I created using the Stream_to_Feature tool. The attribute table contains several records representing different lines - the problem is the ...
4
votes
3answers
2k views

Comparing two point shapefiles that contain lat/longs and compute distance using ArcGIS Desktop?

I have 2 sets of point shapefiles in ArcGIS Desktop (group A and B), each set has around 1000 entries that contain lat/long. What I want to do is compare Group A against Group B and figure out for ...
2
votes
2answers
2k views

How to perform trilateration using 3 lat/lon points without distances?

I read this thread Trilateration using 3 latitude and longitude points, and 3 distances explaining about trilateration using 3 latitude and longitude with measured distance. The problem is I want to ...
7
votes
3answers
315 views

How to check if parcel is located by golf course

Is there any simple way for me to run millions of parcels through some type of script to see if a shape file parcel is on a golf course? For example if I have a layer that has all the golf courses and ...
4
votes
3answers
3k views

How to properly utilize DWITHIN Spatial Filter in OpenLayers

Given the following code: var points = []; points.push(new OpenLayers.Geometry.Point(-110, 38)); points.push(new OpenLayers.Geometry.Point(-108, 40)); var lineString = ...
4
votes
1answer
772 views

Calculate coordinate ( lat / long ) with another coordinate and distance

I already have a formula that can calculate the distance between 2 geographic coordinates: public function getGeoDistance(Coordinate $geoCoord1,Coordinate $geoCoord2){ if(is_object($geoCoord1) ...
3
votes
3answers
764 views

Looking for a Java library for tracking positions, and querying regions

I have a deceptively simple requirement to create a software component to record and update some mobile position information, then be able to perform simple queries concerning mobiles in a particular ...
4
votes
2answers
787 views

Plugin for average distance from node to polyline in QGIS?

Is there a plugin available that will calculate this? EDIT 1: The red polyline is the average distance of the point to the black polyline. The red polyline is what I want to display. Alternatively, ...
4
votes
1answer
991 views

Does the Bing Maps API have a distance to coast service?

Does the Bing API contain a distance to coast service from an address? All we need to do is calculate the distance to a major coastline (Atlantic or Gulf of Mexico).
1
vote
2answers
310 views

normalizing Haversine distance

I need to normalize the Haversine distance. What's the maximum Haversine distance ? The Earth circumference I guess ? how much is it ? thanks
0
votes
0answers
167 views

Is there a tool that tells how many features there are within a set distance in ArcView?

I'm looking to create a raster, in ArcView, that represents how many features (either points or polygons) are within a certain distance from any given location within a study area. I know there must ...
2
votes
1answer
1k views

Transform polygon to equivalent circle, QGis

I have a polygon and I'd like to find the radius of an equivalent circle from a particular point within the polygon. The polygon would have a large (infinite) number of points evenly distributed ...
9
votes
2answers
3k views

Measuring distance in spherical Mercator vs zoned UTM

I've got points in WGS84 lat/long and I'd like to measure "small" (less than say 5km) distances between them. I can use the haversine formula from http://www.movable-type.co.uk/scripts/latlong.html ...
5
votes
2answers
3k views

Calculate distance of points along a route

I am struggling with the calculation of the distance between points along a stream (points are located 0-20m away from the stream) in ArcGIS 10. The points are simple xy-data in UTM. I created a ...
6
votes
2answers
286 views

Metric/parameters to compare length of polyline

What would be a good metric to compare the length of two polylines? A very naive approach would be to define a maximum delta which the two lines can differ. I'm looking for more approaches. For ...
38
votes
5answers
10k 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 ...
13
votes
5answers
16k views

Finding distance of point along polyline?

We need to find the distance of a series of point along a given polyline. We have a polyline dataset repsenting rivers in a catchment, broken up into river reaches (FID 1 through 35 for example). We ...
3
votes
3answers
776 views

How do you produce a output table containing distances between mineral grains at various azimuthal directions?

I am using ArcGIS 10, the newest version and I am a senior at Western Carolina University and working on my senior thesis and the data set in which I have are images of mineral thin sections all ...