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

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4
votes
1answer
400 views

How to access the road graph plugin in python?

I am developing a few scripts in Python for QGIS 1.8 to automate some geo-tasks and one of them would be to calculate the shortest distance from a hospital to each building in a town. I would like to ...
3
votes
1answer
149 views

Get the total distance from a point to the end of a linestring

I have a list of GPS coordinates that make up a bus route: busRoute = [(x1, y1), (x2, y2), ... (xn, yn)] I also have a point that may not be exactly on that route (due to GPS error): ...
1
vote
1answer
141 views

What is the preferable value for setting tolerance for selecting a feature

I know it's really a basic question. But I am really confused about this. For selecting a point feature by mouse click, we need to set a tolerance value to create the envelope. And here is the problem ...
1
vote
1answer
968 views

postgis distance calculation between points with lat, long coordinates

Team, I am new to postgis, but a postgres user for quite a while. I would like to compare the geospatial capabilities between postgresql and mongodb. I have the lat.lon, zip code of US locations; ...
3
votes
1answer
281 views

What formula does SQL Server 2008 use in STDistance?

I am analyzing the accuracy of the STDistance function for geographical objects in SQL Server 2008, in order to understand its behaviour better I need to find the underlying formula. Does anyone ...
13
votes
2answers
2k views

What is the approximate error of the Pythagorean Theorem vs. Haversine Formula in measuring distances on a sphere at various scales?

Many people when first trying to calculate distances between two longitude / latitude pairs ask if Pythagorean theorem works as an appropriate distance function. Most often people answer "no, the ...
0
votes
1answer
59 views

error in estimate distance?

i do some experiment place two sensor node between them 4 meter as distance. then i get these GPS information: node1: Latitude: 32, 33.255 , Longitude: 36, 0.6632 node2: Latitude: 32, 33.228 , ...
4
votes
1answer
343 views

How can I make a Postgres/PostGIS ST_Distance_sphere query more efficient?

Within Postgres/PostGIS I have written an SQL query to get the closest distance for each element within a point coordinate table from a polyline table. The query comes back and works correctly, but ...
1
vote
1answer
425 views

Accurate and fast nearest neighbour, which distance function should I use and how to it speed up? [duplicate]

I am solving the following problem: I have a map with many points in it and I need to find the nearest point to given location. Each point carries information about it's latitude and longitude. This ...
3
votes
1answer
521 views

How to create points at shortest euclidean distance to other points?

So, I have a lot of points, and I need to site three new points so they will be at the shortest euclidean distance between all of the other points. In other words, these three new points that I need ...
3
votes
1answer
527 views

Pivot a polyline at vertex or distance using ArcObjects C#

I hope you can help me with that one. I'm using ArcObjects with C# trying to rotate only one part of a polyline at a vertex or distance along the polyline. The polyline is zAware and has values at ...
0
votes
0answers
153 views

Offset a Polygon defined in Lat Lng points by a given distance of miles or km

I am trying apply a positive offset/buffer (enlarge a shape equally from the borders) to a polygon that is made up of a series of latitude/longitude coordinates by a distance that is defined in either ...
3
votes
1answer
345 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) ...
0
votes
0answers
20 views

Distance from rivers-Zonal Statistics [duplicate]

I am using arcgis 10.1 I am trying to calculate euclidean distance from each feature using this large rivers shapefile http://www.arcgis.com/home/item.html?id=44e8358cf83a4b43bc863646cd695945 . And ...
0
votes
1answer
127 views

How to set the length of a line using openlayers

I'm trying edit a polygon by changing the length of some lines by code. Found this method to calculate based on the bearing. But I didn't find anything on how to calculate the bearing, before I start ...
2
votes
1answer
333 views

Correct coordinate systems, but trustworthy distance between points?

I have limited GIS experience with projections and I have some questions about trying to accurately display point data from two different sources in ArcGIS 10.1 in order to do a proximity analysis. ...
9
votes
1answer
255 views

Measuring distances between simultaneous points

I am working with GPS data and so I have UTM's with DATE/Time information. I have 2 groups of species (moose and wolves). I want to join the information from moose to wolves that match in time. So, ...
1
vote
1answer
609 views

Get the distance from a point on a polyline to polyline's from point

I have a polyline and a point on the polyline. I need to find the distance from the from point of the polyline to that point. ICurve.QueryPoint method does the opposite thing. It gives a point ...
2
votes
1answer
534 views

Trilateration 3D - Vincenty's Formula

with reference to Trilateration using 3 latitude and longitude points, and 3 distances. The accepted answer was votes as shown in wikipedia at: http://en.wikipedia.org/wiki/Trilateration in ...
4
votes
1answer
214 views

Distance from waterways

I have an sdc file with water bodies, i.e. oceans-rivers-lakes. I want to combine it with a shapefile with the boundaries of countries all over the world and produce two measures: 1) The average ...
0
votes
2answers
236 views

Road network Analysis

I have a Road layer and Point features of some Bus stops from the same area.I want find the Road distance between the Bus stop.Please help me find it. I have QGIS,ArcGIS,and FME. Thanks, RKM
1
vote
0answers
355 views

Get the distance between 2 WGS84 GEOSGeometries

I currently want to check if 2 given GEOSGeometry objects of type Point are within 100m of each other. (length flexible) Looking at previous asked questions on this topic, most of the answers were ...
3
votes
2answers
787 views

Calculating the distance from each point in one layer to the nearest point in another layer

I am trying to find the average distance from several points in a layer to points in another layer. I am using ArcMap Basic - I know there is a way to do this using the Advanced version of ArcMap but ...
7
votes
4answers
527 views

How to calculate the “depth” of a linestring using postgis

I have linestring features, which look like bent linestrings, hemicycles or convex or concave linestrings. In the moment I can select the distance between the startpoint and endpoint of each feature. ...
3
votes
2answers
561 views

Calculating the distance between points and multiple lines

I have a point shapefile of about 100 points and a polyline shapefile of about 200 lines and I am interested in finding the distance between every point and each individual polyline. My polyline ...
4
votes
1answer
324 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 ...
3
votes
1answer
262 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 ...
8
votes
2answers
640 views

How do I group near points with GPS positions?

I'm an IT person so I don't know too much about projections and so on, I hope you can help me. I have made an application for Android that collects a GPS position, so I have the latitude and the ...
1
vote
1answer
269 views

Rasterize vector with gdal

"I would like to calculate the Euclidian distance from a residence to a public service of interest e.g. the distance from a residence to a green space (as the crow flies) in QGIS. After browsing the ...
1
vote
1answer
523 views

QGIS, Euclidean distance analysis [duplicate]

i wanna generate euclodian distance map for my road data. I 'll use it for multi criteria analysis. I can get it by using Arcgis Euclodian Distance tool but i wanna generate it in QGIS environment. I ...
0
votes
1answer
123 views

How to find features within a distance? [duplicate]

I insert the values from lat/long into the points. Those users move around and send me new Lat/long and of course , I made an update of the position. I need to find people that are in a distance ...
3
votes
4answers
1k views

Calculate min distance between points in PostGIS

I have point layer in PostGIS database. Help please with query which add for each points in layer distance in attribute table between this point and another nearest point. Thanks! Update Calculate ...
1
vote
0answers
70 views

Allocate places according to distance

I've asked this over on Stack Overflow but thought that someone may have a GI point of view that may help: As an over-simplified example I have a list of events that have a maximum attendance: ...
4
votes
1answer
2k views

Calculate distance between X/Y coordinates by individual in R

In R, I'd like to calculate the straight-line distance between each capture of an animal in my dataset - no need to take into account the curvature of the earth. I have a dataset that looks like ...
8
votes
1answer
496 views

Calculating distance from points to different class in raster

I am looking for some advice on how to calculate the distance from a point to a different class of a raster. Specifically, I have observations (points) of animal use overlaid on land cover data. For ...
1
vote
0answers
485 views

Distance Matrix in QGIS

Can anyone help me with the distance matrix tool in QGIS? Is there a tutorial about it? It sometimes crashes when I use it and the values that it produces seem strange. I am a beginner in QGIS, so I ...
1
vote
2answers
251 views

Why is pgrouting driving distance skipping edges?

I have a road network where I do a driving distance operation through pgrouting. This is my SQL: SELECT * FROM driving_distance('SELECT gid AS id,source,target, cost FROM ...
0
votes
3answers
356 views

Calculate 'Rectangle' Coordinates Given 2 Points and width [closed]

I want to create a rectangular polygon using two points as guides. So let's say a journey starts in Egypt and ends in London, my polygon should have 4 points: 10 miles further from London than Egypt ...
4
votes
2answers
1k views

Spatial distance analysis in QGIS

I'm quite new to QGIS and trying to figure out how to analyze the following problem. I have three layers: settlements point layer with 253 entries waste treatment facilities point layer with 24 ...
5
votes
1answer
646 views

Calculating distance in WGS84 (MySQL and Geoserver)

Here is the environment in which I work: An application using geo-referenced data Database MySQL 5.5, storing georeferenced points A Geoserver server, connected to the MySQL database Here is the ...
2
votes
1answer
414 views

How to Determine to world map size in pixel given this data?

How to Determine the world map size in pixels given this data? Map size of a particular area say, for example: Makati city, Philippines with bounds: Top-Right: 121.0281, 14.56497 Bottom-Left: ...
13
votes
3answers
581 views

How can I represent distance using the dashes or markers of a vector line?

I am a very basic user and dont know the lingo to get to the gist of my question so some background might help. Ive volunteered to create a pre-incident planning system for my rural fire department. ...
4
votes
1answer
205 views

API for time and distance between two addresses?

The Google TOS appears to limit the use of API for time and distance between two addresses to use in conjunction with a displayed map. Does anyone know of any other mapping data source that offers a ...
5
votes
1answer
820 views

Distance Matrix tool in QGIS. How to get result in metric? [closed]

I'm trying to calculate the distance between points in layer with distance matrix tool. And keep getting strange results no matter what. Like this MASTER ------------SLAVE ---------------- DISTANCE ...
5
votes
5answers
2k views

How to calculate distances in a point sequence?

I'm looking for help calculating the distance between a sequence of points that are in a single Shapefile in QGIS. Below is what my data look like and a blank distance column I've added to show how ...
1
vote
0answers
22 views

How to perform a join on simultaneous spatial and attribute criteria in PostGIS [duplicate]

Possible Duplicate: How to perform a join on simultaneous spatial and attribute criteria in ArcGIS? I have two point layers and want to perform a spatial join on nearest distance. I have a ...
2
votes
1answer
930 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
2k 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 ...
2
votes
1answer
564 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
187 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 ...