Tagged Questions

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

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3
votes
1answer
76 views

GDAL 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 ...
1
vote
1answer
152 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 ...
0
votes
1answer
107 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 ...
4
votes
2answers
899 views

tool to find the routing distance between two latitude/longitude points using OSM data

I need a tool to find the distance between two points whose longitude and latitude are given. I am making an application so it will require bulk queries, so i cannot use google maps distance matrix ...
0
votes
1answer
66 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 ...
2
votes
2answers
194 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
55 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: ...
3
votes
1answer
139 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 ...
1
vote
1answer
557 views

Calculate the distance between two contours

I have two contour polylines (single shapefile) and I would like to calculate the mean, min and max distances between the two lines. Is there a function in ArcMap 10 (ArcInfo license, incl. Spatial ...
7
votes
1answer
139 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
162 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
189 views

Network distance computations using GRASS

I'm an ArcGIS user who's interested in learning to use GRASS. Can anyone point out resources that will help me in learning how to obtain network distances between (1) residential locations (points) ...
4
votes
1answer
322 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 ...
0
votes
3answers
214 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 ...
2
votes
1answer
112 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: ...
12
votes
3answers
193 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. ...
6
votes
5answers
2k 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 ...
4
votes
1answer
172 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
1answer
207 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" ...
14
votes
1answer
499 views

How accurate is approximating the Earth as sphere?

What level of error do I encounter when approximating the earth as a sphere? Specifically, when dealing with the location of points and, for example, the great circle distances between them. Are ...
1
vote
0answers
19 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 ...
0
votes
0answers
50 views

How accurate is spherical geodesic distance? [duplicate]

Possible Duplicate: Approximating earth as sphere We are in a situation where spherical distance computations may be more convenient and faster than ellipsoidal ones. However, I am ...
2
votes
1answer
146 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
150 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
161 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
373 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
90 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
98 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
123 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?
5
votes
2answers
257 views

Dissolving polygons by attribute and in a certain distance (ArcGIS)

in a FeatureClass I have a lot of polygons which contain attributes of different landuse-types. Now I am trying to dissolve those polygons of the same landuse-type, but only if the distance between ...
6
votes
1answer
330 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
0answers
150 views

calculate total Miles in a polygon using Google Map

I have an application that allows the users to create any custom polygon layer on top of google maps, i am interested to know if their is a way to select the road layer in this polygon and then ...
2
votes
3answers
340 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 ...
5
votes
4answers
819 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 ...
3
votes
0answers
324 views

Performing a Multicriteria Analysis Using Distance Along a Road Network

There is the possibility that I will be working on a project which will look at thousands of properties in a region and measure their accessibility to different services (schools, parks, hospitals, ...
1
vote
1answer
243 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
154 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
38 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
126 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 ...
0
votes
0answers
48 views

Interpretation of MODIS VCF Data, concerning walking distance analysis

I'm still working on my diploma thesis (must be one of the last ones in germany..;)) which deals with distance analysis. I want to model walking distances and cost paths affected by slope, vegetation, ...
2
votes
1answer
210 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
718 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
286 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
101 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
99 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
2answers
2k views

How to generate random locations nearby my location?

I am trying to create random locations nearby my location. What i want is to create random latitude/longitude pairs inside a 200 meters circle surrounding my location. This is the formula i came up ...
7
votes
5answers
810 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
3answers
1k 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
192 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
204 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 ...

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