# Tagged Questions

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

140 views

### How to create a map colored by distance to nearest point in R

I'm new to GIS and R-- hope this question makes sense. I have a dataframe(geo07) containing two variables that record the long/lat values for about 6000 points (mat_long & mat_lat). These ...
132 views

### calculate distance between points crossing the antimeridian

How can I calculate the distance between two points (lon/lat) if any of the points exceeds the antimeridian (+-180 longitude)? Im using the distVincentyEllipsoid {geosphere} to calculate the shortest ...
3k 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 ...
2k 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 ...
877 views

### Create raster distance around a single point feature class

Okay, so I'm relatively new to ArcMap and I'm trying to use the Fuzzy membership for suitability test. I have a single point feature class that I want to use for this analysis. I know that in order to ...
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 ...
277 views

### How to calculate the shortest geographical distance between a line and a point? [duplicate]

I'm trying to calculate the shortest distance between a line (described as a pair of [lat, long]s) and a point (lat, long) accurately. I've read many Wikipedia pages, but I'm new to the topic. I've ...
101 views

### Distance from centre point to other points using QGIS?

I have a question of something I actually thought was pretty simple...I have a few points around a centre point. Now I want to know the distance from each point to the centre point. Is it possible to ...
1k 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 ...
202 views

### PostGIS: Get closest point between geometry and Multipoint

I think my question is not that difficult for GIS professionals, but i didn't found an answer to my problem (even not in other questions). Problem: I have given two tables (table1,table2) with Points ...
171 views

### Finding areas with high POINT density from PostGIS table using Python

I have a PostGIS table with thousands of POINT objects and I want to find areas that have a high density of points. I have the DBSCAN clustering algorithm implemented in Python which does exactly ...
242 views

### The ratio Pixel distance to geographical distance?

I have had this problem for several days and I have no idea to solve it. The problem is that I am trying to find out the length and width of ships from a Bing map. I got the location point (lon, ...
33 views

### Calculation size limit to creating distance matrix using QGIS?

I have a shapefile of postal code for a city (Montréal). I would like to calculate the distance between all postal code. I tried to run the distance matrix after converting all postal code to a ...
154 views

### Find point close to points from postgis table

I have a postgis point table with a large list of cities. I need to find duplicates in it, but only if they are 10km close each other, which means that is the same city. For example, I have 5 points ...
172 views

### Calculating Distances between coordinates

I have perused through the other questions that are very similar to mine but am still having some trouble. I have 75 coordinates in WGS84 that I brought in from an Excel table. They are now on my ...
212 views

### Statistics: Estimating U.S. population-weighted average temperature from 100+ daily airport station measurements

I have recently signed up for a developer's key for the Census API (http://www.census.gov/developers/) and will be using a Python wrapper class to access the Census database. My goal is to find the ...
82 views

### <#> doesn't give a useful distance [duplicate]

I'm new to postgresql/postgis and trying to measure a distance. So st_distance() may be the most accurate, it's the slowest too (as I've read). I read that one can use geometric (instead of ...
117 views

### Calculating distances from points to the centre of cells

I am using QGIS 1.8.0 (using older version because I need the Qmarxan plugin which is not available for 2.4.0). I have a study area that has a vector laying of "planning units", or cells over the top ...
35 views

### How to calculate distance from point to polygon with a time frame?

Using the Near tool, I knew that I can just calculate the distance of each house to the nearest fire. However, I only want to keep fires that happened in the past 7 years for each house. For example, ...
299 views

### What is an efficient Algorithm to draw a straight line from points?

I have some cross section survey data, which is like this: X Y Z pt_dt 2970969.635 359725.0088 83.4242 1-x 2970968.278 359722.2182 83.2591 1-x 2970941.771 359670.127 83.0655 1-x 2970961.369 ...
253 views

### Create circles around a point on a map measuring the radius in hours

Disclaimer: I am not experienced in GIS and hope this question fits in this category. I was wondering whether it is somehow possible to create a circle* around a city, using Google Maps or the like, ...
423 views

### How to measure correct distances in a project with OpenLayers background?

I have 3 lat/long points as follows: A = {35.257246,139.721256} B = {35.256541,139.721491} C = {35.256326,139.7203271} 1) Measurement result by Movable Type Scripts: By using the distance ...
823 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 ...
360 views

### Is there a way to calculate closest distances to a point without using Near Analysis?

I frequently get asked to calculate distances from a specific point (A drilling well in the middle of the sea for example) to a number of Environmental layers (Protected Areas, Pipelines, Other wells ...
52 views

### Calculate distance for point to point based on value in field of first point

I am trying to figure out the best way to calculate the distance for each student from the school they attend. We have 2 shapefiles - the student locations with a field identifying the school they ...
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 = ...
420 views

### Calculate distances between polygon centres in QGIS

Is there a practical way to calculate distances between polygon centroids in QGIS? I have a UK city region map divided into administrative units (1 ward = 1 polygon). I want to represent their ...
215 views

### How to show average walking distance to closest point in census tract in ArcMap?

Given a map layer of point locations, and a second map layer of census tract polygons for the same area, how would you create a map layer that shows the average walking distance to the closest point ...
77 views

### Buffering algorithm [closed]

Does anyone know the algorithm of buffering? I had difficulty in drawing buffers. So I tried many values to acquire 1km buffer. I found value 0.008966 produces 1km buffer. Then I calculated inverse ...
449 views

### How do I calculate Manhattan distance with PostGIS?

I am using the ST_Distance function to calculate the distance between two geometries (a train station and a building) Since I know that all buildings and all train stations are in Chicago, which has ...
36 views

### Scale on map requires correction coefficient. But why? [duplicate]

I am computing the distance of a map I am getting from ArcGIS' REST services by using a calculator as provided by this answer. In a nutshell, it uses a GeodeticCalculator for distance computation ...
68 views

### How to set a defined distance between nodes to digitize in qgis?

Using QGIS (by now I have the 2.4 version) I would like to set some parameter (I don't know if such exists) that would impose a definite or maximal distance between nodes when digitizing a polyline or ...
270 views

### Distance Between Two Points vs Length of Linestring

So I have two points that I want to calculate the distance between. If I use: SELECT ST_Distance_Spheroid(point_a, point_b, 'SPHEROID["GRS 1980",6378137,298.257222101]') / 1000 FROM ( ...
251 views

### GeographyFromText and ST_SetSRID+ST_MakePoint different results?

Why am I getting different results? SELECT ST_DISTANCE( ST_GeographyFromText('SRID=4326;POINT(13.401111 52.383343)'), --berlin ST_GeographyFromText('SRID=4326;POINT(9.997559 53.533778)') ...
303 views

### How to calculate the distance of sites to riverways

How do you calculate the distance of about 10 sites scattered across a region to bodies of water (rivers and lakes) using ArcGIS 10.1? I have the lat/lon coordinates of the 10 sites as a point ...
143 views

### GeoDjango order_by('distance') not working as expected?

Using GeoDjango, I am trying to sort a list of users based on the distance from a point. It does generate a list, but its not ordered by distance, though I specify that in my query. This is the query ...
413 views

### Calculating distances between consecutive points along rivers (polygon) using ArcGIS Desktop?

I have radio-tracking locations of semi-aquatic mammals. Now, I would like to calculate the distance between the consecutive locations using the river as the animals would swim (opposite to as the ...
70 views

### Calculate distance in point collection algorithm

I've got collection of points which are sorted by x,y and distance between n and n+1 (array of objects [{x:0,y:0},{x:1,y:1}....] I would like to calculate distance between all points (point 1 distance ...
342 views

### FME - calculating distance to points along a line

I am new to FME, and trying to get my head around what should be pretty straightforward issues, but I find myself going around in circles Basically I want to determine the distance (chainage) to a ...
121 views

### Determining closest representation of polygon as collection of points+radii

Have a bit of a tough question, which I realize there may not be an easy solution to. Figured what better place to ask. I'm attempting to transform a polygon into a series of arbitrary points with ...
524 views

### Calculate distance using 2 sets of lat/long values in the same record

I have a point layer with over 90K records in it. For each record I have lat/long field for incident, and lat/long for engine location. Is there a way to find the distance between Incident point and ...
5k views

### Splitting lines automatically at specific distances using ArcGIS Desktop?

I have a set of polylines which I need to split at varying distances from their starting points. In general, I'm looking for a something similar to the SPLIT function within the editor tool. There ...
842 views

### Calculating distance between two sets of Decimal Degree coordinates?

I have coordinates in decimal degrees e.g: point A:Lat,Lng(5.317101667,-2.023303333) and point B:lat,lng(5.317093333,-2.023318333). The altitude in Meters at Point A is 11m and the altitude and Point ...
53 views

### Devising measure of vertical distance from spring line?

I am building a model (using Logistic Regression) to explore the relation between a binary categorical dependent variable (parcels agricultural production quality) and several predictors, among which ...
312 views

### Distance from rivers, taking into account terrain elevation

I am interested in building a raster of the distance from rivers in a territory under study. I have digitized the course of the rivers in ArcGis 10.1. I have used the 'Euclidean Distance' tool to ...
240 views

### Calculate distance between point and linestring and how to represent that on QGIS?

I have loaded my data with osm2pgrouting and I have my network with ways (Linestring) and nodes (Point). The problem is : I have a database of doctors addresses (point) and I should calculate the ...
274 views

### MMqgis (hub distance) error in distance

So I am trying to calculate the distance of several points to a coastline, using hub distance (mmqgis plugin) in Qgis Dufour 2.01. I am using the default coordinate system (WGS84) and I, already, ...
509 views

### Using grayed out distance/direction tool in ArcGIS for Desktop?

I have a set of five points (all with specific latitudes and longitudes) and I want to create a set of points which will be about 80 kms from the first set. I understand that I can use the ...