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

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2
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1answer
777 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 ...
0
votes
0answers
164 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
490 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 ...
5
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 ...
4
votes
1answer
170 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 ...
7
votes
2answers
142 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
237 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?
8
votes
1answer
768 views

Problem analysing movement using cost surfaces (involving ArcGIS's 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 ...
2
votes
3answers
1k 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 ...
8
votes
4answers
1k views

Looking for a fast, open-source raster cost-distance function to use in code

I've been scouring the internet for a fast, open-source cost-distance function that I can embed inside my code. The functionality should basically work like the ArcGIS implementation where I can ...
1
vote
1answer
522 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 ...
1
vote
2answers
256 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
45 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
211 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 ...
2
votes
1answer
411 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 ...
1
vote
1answer
2k views

How to get the shortest distances between features on separate polygon layers?

Suppose I have a county-level map for the state of North Carolina, U.S. Suppose I would like to compute the shortest distance of each county to any point along the border of Georgia. How would this ...
1
vote
2answers
573 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 = ...
3
votes
1answer
133 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 ...
0
votes
1answer
111 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 ...
7
votes
5answers
2k views

Calculate distance in km to nearest points (given in lat/long) using ArcGIS

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 ...
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 ...
3
votes
1answer
339 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
297 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 ...
1
vote
0answers
116 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 ...
5
votes
2answers
5k views

How to calculate new point coordinates from distance and angle?

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 ...
2
votes
1answer
95 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 ...
8
votes
2answers
1k 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 ...
1
vote
0answers
25 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 ...
0
votes
0answers
431 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
2k 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 ...
2
votes
1answer
711 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 ...
4
votes
3answers
3k 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 ...
19
votes
2answers
410 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 ...
6
votes
2answers
385 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
783 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 ...
4
votes
1answer
419 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 ...
3
votes
1answer
203 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
153 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
1k 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 ...
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 ...
1
vote
2answers
2k 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 ...
2
votes
1answer
397 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 ...
2
votes
0answers
792 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
446 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
1k 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", ...
1
vote
1answer
2k 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 ...
4
votes
4answers
2k views

Geodjango- get the distance between 2 points

Sorry to be asking yet another geodjango newbie question. What I want to do is quite simple, I have 2 locations defined by gps coords, lat / long like returned by google maps: ...
6
votes
1answer
2k 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 ...
5
votes
1answer
597 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 ...
4
votes
1answer
576 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 ...