The measure of separation between two entities or locations that may or may not be connected, such as two points.
2
votes
1answer
76 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 ...
10
votes
3answers
2k views
How to cluster spatial data in R?
I am very new to R, so please bear with me : >
I have bunch of data points with latitude and longitude. I want to use R to cluster them based on their distance.
I have already taken a look at this ...
8
votes
2answers
677 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
23 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 ...
7
votes
3answers
4k views
How do I calculate the bounding box for given a distance and latitude/longitude
Hi need to be able to calculate a bounding box or circle for a Given WGS84 latitude and WGS84 longitude, and distance but have no Idea where to start! The distance from the start lat Lon would be 10KM ...
0
votes
0answers
261 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
927 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
0answers
73 views
finding a location on a line using a point and a relative distance with arcgis js api
The problem I'm trying to solve is to find a point on a line given another point on the same line and a distance from the same point. I've been looking on the various RouteTask examples but they ...
2
votes
1answer
404 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 ...
3
votes
3answers
1k 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
340 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
237 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 ...
7
votes
1answer
534 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
218 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 ...
2
votes
1answer
2k views
Calculating the minimum distance between points and polygons in QGIS
I have two vector layers: one point and one polygon and I want to calculate the minimum distance of each point from the polygons (ie the distance from the closest point of the closest polygon). Is ...
5
votes
1answer
116 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 ...
3
votes
1answer
145 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
114 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
872 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
726 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 ...
1
vote
1answer
219 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
417 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
254 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 ...
2
votes
1answer
1k views
How to find nearest point for each point in current layer?
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 ...
4
votes
1answer
771 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
776 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 ...
2
votes
4answers
1k 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:
...
4
votes
3answers
2k views
Splitting lines automatically at specific distances?
I have a set of polylines 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 it is ...
3
votes
1answer
1k 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
351 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
333 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 ...
3
votes
2answers
516 views
How to calculate how long an arc second is for a given long/lat?
The title says it all, really. I am wondering what area is covered by a dataset which is one arc second wide.
Thanks,
Rob
7
votes
3answers
194 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 ...
3
votes
2answers
512 views
How do I get the distance meter value between two geometries in PostGIS?
I have a simple question about calculating distances in PostGIS.
I would like to get the distance between two geometries. I am using this sid : 4269 in meters
what i am doing now is this : ...
7
votes
1answer
411 views
Appropriate distance metric for spatial clustering of geographic coordinates
I have a set of locations in geographic coordinates, and I would like to group the points using hierarchical clustering followed by tree-cutting at various "heights" in order to calculate group-wise ...
4
votes
1answer
235 views
Projecting gps data to get length of resulting line shape in ArcMap 10.0
I have gps data in WGS84 geographic coordinates. I will use the gps data to build a line shape in ArcMap 10.0. The data falls in UTM 15N.
To get most accurate length of line, should I project the ...
3
votes
3answers
3k views
Distance between GPS coordinates
Given a database of GPS points, a center GPS location, and a radius R (in meters), how can I find all points in the database that are within a distance of R of the center point?
Will the distance ...
3
votes
2answers
110 views
How to find the distance within which a set percentage of features fall?
Someone asked a question earlier about finding the number of features within a certain distance of another feature in ArcView. I have the opposite question: is there any way, in ArcGIS 10, to find the ...
3
votes
1answer
804 views
How do I perform a proximity search with Postgis?
OK, so I downloaded the Geonames database (cities1000) and wrote a small Ruby program to import them into my table (geo_cities). I then added geography column called geog.
So after all of that, I ...
2
votes
1answer
331 views
Calculating distance from points to nearest “eastern” polygon
I am using ArcGIS 10, and trying to do the following:
I have a layer file of points (industrial facilities), and I would like to calculate the distance from each point to the nearest "eastern" ...
4
votes
3answers
2k 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 = ...
7
votes
4answers
4k views
Calculating Lat/Lng X miles from point
I am wanting to find a latitude and longitude point given a bearing, a distance, and a starting latitude and longitude.
This appears to be the opposite of this question (Distance between lat/long ...
1
vote
2answers
296 views
QGIS layers no longer overlay when Enable 'on the fly' CRS transformation is on
My QGIS project has two layers - one retrieved from GADM (administrative boundaries of Guinea Bissau) and another one of the villages collected in the field using GPS Decimal Degrees - D.ddddd.
If I ...
2
votes
2answers
537 views
Finding the minimum and maximum distance between an observer and a lat/lon bounding box
I have three points in geographic coordinates (latitude, longitude, altitude). One of the points represents an observer, above the Earth. The other two points define a bounding box. I'd like a ...
3
votes
1answer
934 views
Calculating distance to points in QGIS
Is there a way of calculating the distance to the nearest points in QGIS? In ArcGIS there is a function called Euclidean Distance, which can take an input vector or raster, and generate a raster of ...
3
votes
2answers
400 views
Distance Calculation Output Does Not Identify Input Points
I'm using ArcMap 10 to do distance calculations between a large set of points, using the point distance calculator. The output table generated gives me distances correctly, but the output categories ...
14
votes
1answer
530 views
Monte Carlo simulation using QGIS and pgRouting on optimal sidewalk construction
I am new to spatial analysis and would appreciate some general direction on a project I am attempting, outlined below (I am starting from scratch).
GOAL: To find the best locations to install 2000 ...
3
votes
2answers
2k views
How to use Distance Matrix tool in QGIS?
I have a point data set. Now there are cluster of points based on a field. So I take out one such cluster which has points with same field.I want to find distance between all the points in cluster and ...
6
votes
3answers
399 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 ...
