Tagged Questions

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

359 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 ...
1k views

Toblers's Hiking Equation and Slope Dilemma

I'm trying to use Toblers's Hiking equation to determine economical backgrounds of some hillforts. The equation is anisotropic which means that the speed of movement that it calculates differs whether ...
540 views

Finding distance between consecutive points using ArcGIS Desktop?

I am wondering how I can get the distance between consecutive GPS locations in ArcMap 10 (i.e. the distance between consecutive GPS locations sent in during a wildlife telemetry study).
2k views

projection change to create buffer in QGIS

I am about to become desperate... I like to create buffer around several points - if possible - with a declaration of the size in km of these buffers. Just to show you what I am working with: My ...
570 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 ...
1k 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 ...
47 views

Finding distance between points in two different layers along route in ArcMap?

I need to find the distance between points in separate layers along a stream network. I have source sites for macro-invertebrates and sites where they are lacking. I need to find the distance between ...
185 views

Calculate nearest distance in ArcView, XY coordinates

I am really lost and struggling because I have never used an Arc system before. I have two datasets. One with house locations, and the other with investment locations- each locating by XY coordinate. ...
837 views

geotools Linestring distance in meters

I want to use geotools for working with gis data. I'm most concerned about distance calculations, not so much about drawing a map. What I still couldn't figure out is how to make distance calculations ...
575 views

Converting from kilometers to degrees distances?

We have geometries in a Postgis database with SRID WGS84 and we have found lookups directly in degrees to be much faster than in kilometres, because the database can skip the projections I would think....
9k views

Which tools and methods can be used to create isochrones?

I'd like to get an idea for what's involved in creating isochrones for a series of sites, with a reasonable degree of accuracy to the estimates. A general outline would be great, though my scenario ...
2k 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 ...
1k views

Total great circle distance along a path of points (PostGIS)

I am looking for an SQL query that sums the distances between a series of points using PostGIS. The situation is as follows: I have 2 tables: tracks and points. Points belong to a track and thus ...
3k 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 ...
1k 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 ...
11k views

Return all results within a 30km radius of a specific lat/long point?

I have a table with a column the_geom which contains data similar to: ...
287 views

Identifying south facing mountain land, above an elevation, within a slope range, less than fixed distance from major roadways

This odd question comes from believing that such an analysis is plausible in a GIS system. Only, I don't how to accomplish the various discrete steps implied from the Title, nor where to get a topo ...
288 views

Measuring distance to roads using raster data in ArcMap?

I am using ArcMap 10.1 on a Windows x64 system. I am trying to analyse the driving force of urban land use land cover changes. I have 7 raster files represents distance to roads, distance to river, ...
1k views

Surface distance on DEM between two coordinates

Given two coordinates on a digital elevation model (DEM), how do I compute the actual distance traveled between the two locations, assuming a straight line route? How will changing the resolution of ...
1k views

Analysing movement using cost surfaces with ArcGIS 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 ...
869 views

Identification of consecutive points within a specified buffer

I have a point file, hourly relocations of an animal, and I want to be able to place a buffer around each point and calculate the number of subsequent points which are within the buffer zone. I am ...
634 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 ...
927 views

Draw line between points from multiple datasets

I have 2 point datasets and want a tool or script to draw a line between all points in one dataset to all the points in the 2nd dataset. Is it possible? I have tried ESRI "Point Distance" and "...
224 views

Measure distances between specific features in QGIS for Desktop

I'm completely new using PyQGIS and developing plugins. Currently I have a layer with the X and Y coordinates of electric distribution poles, where each pole is a feature. What I need to do is ...
1k views

Projections appropriate for global analysis that preserve area and that preserve distance (but not necessarily in the same projection)

I am looking for a projection (or a set of projections) that decently preserve distances so that I can buffer every country in the world and have a similar level of minimal distortion for each. I ...
2k 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 ...
2k 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 ...
239 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 ...
901 views

How to measure distance between points based on elevation?

I need to be able to measure distances between points, however the distance need to be calculated in relations to elevation. The points are homes of storytellers from the 19th century and the places ...
12k views

How to calculate new point coordinates from distance and angle using ArcGIS SDK for iOS?

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 ...
886 views

How to use/interpret/visualise a distance matrix with unknown coordinates?

How would you go about using a distance matrix where points have no coordinates, i.e. what useful statistics can be made and how to visualise it in some useful way?
762 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 ...
454 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 ...
121 views

After how much distance does the x,y coordinate system become noticeably distorted?

I'm working with maritime sensors that give information of moving objects it detects, in azimuth, range and elevation, and we convert it to x,y coordinates for our application to be able to process it....
7k views

How to find nearest point for each point in current layer using ArcGIS Desktop?

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 ...
1k 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: 121....
53 views

For Loop Maximum Minimum Distance Between Two Lines

I have a table of line/lane ids in a table called matched_lanes, and I am trying to create a lateral query that on each id in the table to find the maximumum minimum distance between each point. I.e....
672 views

Finding and using data on population density files

I'm attempting to replicate this map for the state of Nevada in QGIS: source: http://www.bostonfed.org/commdev/c&b/2014/spring/map-distance-to-closest-snap-outlet.htm (A SNAP outlet is just a ...
555 views

Query all Object within n kilometer Radius with Hibernate Spatial?

I use hibernate spatial attach a geolocation to a car. My card domain class looks like this: import com.vividsolutions.jts.geom.Point class Card { String name Point location } My program is ...
140 views

Using the accCost() function in R: questions regarding the transition layer

I am trying to use the accCost() function from the gdistance package in R. I load my cost raster using the raster()function from the raster package. According to the documentation, I need first to ...
104 views

GeoDjango - save two Point fields, one for geography and one for geometry

Most of the explanations I've read for geography and geometry seem to suggest that one must only use either geometry or geography, and that the only way to use both is to cast/convert between one and ...
597 views

Way to find minimum value from a group of values - QGIS?

I'm wondering if there is a way to find the minimum value of a group within QGIS? Basically I need to find the minimum distance of each unique value in a table of about 5000 records. I can do the ...
543 views

How to calculate the average distance among set of points as measure of closeness

I have three series (or tables) of points in PostGIS which I want to compare. I would like to know how "close" each series is when compared to the other two. In other words I would need some measure ...
895 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, ...
2k 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 ...
346 views

Constructing a Voronoi diagram using a complicated travel time metric

I have in my possession four sets of shapefiles: 1. Locations (points), around 1000 2. Roads (lines), each road has a speed attribute 3. Terrain (polygons), each zone also has a speed attribute 4. ...
380 views

Calculating average raster to point distances within census tracts

I have some experience using ArcGIS, but mostly with the field calculator in the attribute table/spatial joins, so I apologize if I say something that doesn't make sense. To provide a bit of ...
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 ...