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

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5
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1answer
449 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
970 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
524 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
9k 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
235 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
967 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
16k 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
118 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
469 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
4k 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
919 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
897 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
2k 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 ...
3
votes
1answer
630 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
510 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 ...
7
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
335 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
3k views

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

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
319 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
792 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
847 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
823 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
1k 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).
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vote
2answers
318 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
169 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
293 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 ...
39
votes
5answers
11k 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
17k 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
785 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 ...
13
votes
7answers
19k views

Calculating Lat/Lng X miles from point

I am wanting to find a latitude and longitude point given a bearing, a distance, and a starting latitude and longitude. This appears to be the opposite of this question (Distance between lat/long ...
8
votes
3answers
813 views

What kinds of line segments/edges require high accuracy in a true surface-of-the-ellipsoid representation?

I've been musing (and doing prototype coding) for a 'projection free' geographic codebase with your basic point, line & polygon primitives. Rather than dealing with all the sacrifices that come ...
10
votes
3answers
2k views

What is the right solution (and map projection) to compute distances between points located all over the World?

After my study on map projection I realized that it is very difficult to choose a projection that allows to compute simultaneously the distances between a great deal of points if these points are ...
6
votes
1answer
660 views

Is it impossible to measure Right of Way in ArcGIS?

I'm helping bring CAD people into ArcGIS so that everyone throughout the company is on the same page and there is one database for everything. Right now, one of the biggest hurdles is making sure all ...
4
votes
1answer
459 views

No difference between distances measured in projected and non-projected data

I'm performing measurements of distances in Km between a lot of localities by using the "Point Distance" in ArcGis 9.3. I realized that the results obtained after using projected coordinate system are ...
24
votes
3answers
15k views

Why is law of cosines more preferable than haversine when calculating distance between two latitude-longitude points?

In fact, when Sinnott published the haversine formula, computational precision was limited. Nowadays, JavaScript (and most modern computers & languages) use IEEE 754 64-bit ...
13
votes
3answers
5k views

Algorithm to find nearest point

I've a list of a few hundred cities with their latitude/longitude. Given another location (also in lat/long) I need to find the nearest city. As I don't use any GIS, by now the obvious algorithm is ...
2
votes
3answers
1k views

Distance between a line layer and several other line features (arcGIS 9.3 Arcview Licence)

I have a "Drain" line layer (with 150 lines) that I need to calculate the distance from lines to all objects within 120m. I've tried doing a spatial join and its great but I need more than just the ...