# 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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### How to calculate best path between 2 points from a DEM in Qgis?

I'm analyzing the roads and paths of a region by calculating how effective the communication is in the region. First I calculated the shortest paths between the points using the actual road map. Now ...
31 views

### Calculating areas outside a point

I have a university assignment that requires me to find an optimum location for a land fill site. There are various parameters I need to map. I have managed to map all the ones within a distance of ...
31 views

### Vincenty or (Project + Euclidean) for accurate distances

I posted a similar question on stackoverflow, however was directed here for more help. If my main goal was to calculate distances such that my error was minimised to the nearest metre assuming that ...
62 views

### How to group 10k points into closest pairs?

I was first faced with a problem of grouping 1000 pairs into unique pairs to minimise the total distance - since this was a small number I solved it using linear optimisation: Part 1 - Basic/Naive ...
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### QGIS: Distance Matrix tool omitting some points in output table. (qGIS 2.10.1-Pisa)

I have used the Analysis Tools -> Distance matrix to merge two datasets by the closest points. But in my output csv file, some of my points are left out. In the original datasets, none of these points ...
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### Hive GIS ST_GeodesicLengthWGS84 not returning expected distance

I am trying to find the distance between two points (in meters and not degrees) using GIS Tools for Hadoop by ESRI. The ST_Length provides distance in degrees and hence I used the ...
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### Why this pyqgis code cause crash dump in QGIS?

In ArcGIS there is gp.EucDirection to calculate Euclidean allocation, distance, and direction around a point, Is there equivalent function in pyqgis or gdal? I wrote a script with help of gene and ...
41 views

### Finding distance to closest road (polygon to line) in ArcGIS for Desktop?

For my project I need to find the distance to the nearest road from forest polygons. I'm trying to do a weighted overlay analysis (eventually) for a habitat selection project so I think I need to end ...
23 views

### Perpendicular Distance Markers on Polyline in MapInfo?

I have added chainage to a creek polyline in MapInfo v11.0.3 using the 1999 version of "Distance Marker" by Meridian. It looks poor as it does not have the functionality to create the markers ...
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### PostGIS Get the POINT that is x meters away from a fixed point on the route (LINESTRING)

We have a route network stored in the routes table (LINESTRINGs). Basically every sedment (between two vertexes) is inserted as a separate row in this table. Among that we have a locations table ...
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### Calculate the distance between two coordinates (WGS84) in ETRS89

I have an Excel-file with coordinates (WGS84). From these coordinates I create a line (shp) and transform it (ETRS89). After the transformation I calculate the distance from point to point. I do this ...
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### How to create a shapefile from Excel file including coordinates of points and distances between them in ArcGIS?

I wanted to use network analyst in ArcGIS and I have coordinates of points in the network. However, I could not find a shapefile including road information between these points so far (length of links ...
43 views

### Getting point from known points to specific distance of polyline using ArcObjects?

I want to know the coordinates of a polyline from specific point and distance. I have attached image to clear the specification. say, I have a points B(2,3). I want to know the coordinates of A and C ...
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### Scaling distance by area

For each administrative unit, I calculate the median distance between businesses. However, for larger unit, this distance is naturally bigger (and does not paints a fair picture of, say, the effort by ...
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### 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 ...
664 views

### Why is geography faster than geometry for distance calculations?

Intuitively, I thought geometry would be faster than geography distance calculations, but this says otherwise: ...
31 views

### Get distances between boundaries from an SpatialPolygon and raster pixels

I am trying to calculate the distance from several pixels of a raster to a boundary of some polygons in R as it is showed in the image. I have two problems: How to correctly define a boundary from ...
28 views

### Calculate point location with direction and range

I have a latitude and longitude coordinate pair and I want to find another point location (returning lat and long) but only have the angle/direction and distance from the first point. How can I find ...
57 views

### Measure shortest distance around polygon

How do I measure the shortest distance between two points (1 and 2) with respect to a polygon? So the shortest way around the polygon from 1 to 2.
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### How to create for each point feature an Euclidian Distance raster in ArcGIS

I need some comment on how to create an Euclidian distance raster for a point dataset of about 100 features in ArcGIS. I need to create a raster for each single point. My question is, if there is a ...
18 views

### Google Maps Distance Matrix API - Queries per second?

I'm pretty familiar with Google's Distance Matrix API, but I'm unsure about one aspect of the Usage Limitations. The documentation states that you have access to 100 elements per query (element = ...
44 views

### GeoDjango, distance filter based on database column

I have a geodjango model with fields coverage = 10 * 1609.344 reference_point = Point(-72,45) #or some other lat lng class ServiceArea (geo_models.Model): center = ...
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### Is it possible to use ArcGIS to define a boundary around a self-constructed 3D feature?

I am creating a 3D rendering of a future building and would like to know the distance from which this building would be visible from. Is it possible to use ArcGIS to define a boundary that delineates ...
48 views

### What is the real distance between positions?

I'm trying to figure out what gives me the most accurate distance between positions: Measuring distance directly (using Geod.inv)? Measuring distance in 2D (after transforming to a known projected ...
27 views

### GeoDjango and PostGIS distance query efficiency concerns [closed]

For example, if I want a query that says "show me all houses within 50km from here and order them from nearest to furthest", these are the questions and concerns I have: Assuming we are using EC2 ...
70 views

### Creating a point on edge of closest polygon

My project is looking at a grid in the ocean. I want to capture each ocean point's distance to the nearest coastline as a weight, and then use buffer to capture the sum of nightlight data within a 1 ...
31 views

### Extend line to specific distance or a line

I want to extend my polyline to a given distance. How can I do this. I have attached image to clear my specification. I am using .net in ArcMap . I am also using python in the image, I want to ...
74 views

### Distance in meters between two geographic coordinates

I want to determine the distance in meters between two geographic coordinates. The points are: Lat (deg) Lon (deg) A: -33.3930906 -70.5452765 B: -33.3993212 -70.5468767 So if i calc the ...
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### Points proximity to polygons in ArcGIS for Desktop?

I have a point feature class with 1725 records (spread out over NYC) and a polygon feature class with 13 records (also spread out over NYC). What tools or processes can I use to figure out what ...
46 views

### Select points greater than a certain distance from related points based on shared foreign key id

I have a PostGIS-enabled PostrgeSQL db, using QGIS, with data using EPSG:4326, and projected as EPSG:29903. I have a table with points with pk point_id and a table with images with fk point_id. I want ...
69 views

### Average value of polygons within a set distance from a point

I have two vector layers: one polygon and one point layer. The polygon layer has a value from 1 to 10. I am trying to find the average value for all polygons within or partly within a 1-mile radius of ...
62 views

### Buffer from Point or Polygon with Information from Raster

The intent of this work is to define a buffer around a point or polygon based on information from a raster. For instance if a polygon representing a city and the raster defines how long it takes to ...
41 views

### using a linear solver to get a “centre of gravity” of a set of points

As a programmer, if I have a linear solver available. How can I formulate the following problem as a set of constrains / decisions / goals for the linear solver? I have a matrix of say 10*10, so 100 ...
63 views

### ST_Distance loop

I want to create a postgresql function which calculates the distances between random points who are stored in one table. For the Table: CREATE TABLE s_1( id bigserial primary key, the_geom geometry, ...
38 views

### Create a line from an array and measure its length with PostGIS (ST_MakeLine, ST_Length)

do I understand it correctly that it is possible to create a line out of an array with the function ST_MakeLine()? I would like to create a line from several points (more than two) and then calculate ...
58 views

### Get the 2 points immediately before and after a given point in PostGIS

In the picture below: The given point is C, I would like to select A and B, but not Z (which is closer to C than B but it's not immediately after in the LineString). Note that C is always ON the line ...
54 views

### How to calculate multiple distances between set of points and vector grid in PostGIS?

My set contains the following input data: A set of points and a hexagonal (vector) grid. For each cell in the grid, I want to calculate the driving-distance to each point. I thought this would be a ...
45 views

### PostGIS point distance from polygon not 0 when on edge

I have a pretty simple problem: SELECT * FROM ST_Distance(ST_GeographyFromText('POLYGON((70 -40,70 -39,71 -39,71 -40,70 -40))'), ST_GeographyFromText('POINT(70.48 -39)'), False) returns ...
57 views

### Divide line by length with QGIS [duplicate]

I'm a newbie using QGIS 2.12 and I'm trying to split a line in QGIS and place points every x meters. There is a tool in ArcGIS (divide by length add in). How to achieve this in QGIS?
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### Measuring large distances when all layers are in decimal degrees using QGIS?

I just developed a distance matrix between various points across Canada in QGIS. The distances produced are in decimal degrees, and I would like to view them in metric. I am unsure how to do this.
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### Find nearest road distance between two points for over 1000 points

I'm extremely new to QGIS and am learning the material on my own. I have two CSV files with latitudes and longitudes, one has school address information and the other has fast food restaurant ...
35 views

### How to calculate shortest path from points in one layer to points in another layer via roads, in QGIS

I'm a new user of QGIS (and have experience using ArcGIS but zero programming skills) and I'm looking for a way to calculate the shortest path from addresses to subway stations via a network of roads. ...
85 views

### How to calculate the distance to the nearest water source?

I have a polygon hydro layer of my study area and am trying to calculate the distance to nearest water bodies from my site. Since my site are 2km*2km grids I am not sure how to calculate it? Whether ...
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### Extracting distances along a line from postcode a centroid to the nearest point (bus stop)

I'm looking to measure the distance from postcode centroids (point file) in a city to the nearest bus stop (point file) along the road network (line file). In Qgis I can calculate the distance but ...
26 views

### How can I measure the distance between many polygon features and either another polygon or a line in QGIS?

I often have to manually measure the distance between a single site and other sites around it, but obviously this can get long-winded and I feel like there must be a much more efficient way of doing ...
60 views

### Obtaining road distances between each pair of points in point feature class using ArcGIS for Desktop?

In Calculating attribute for network distance between multiple points in ArcGIS Desktop?, an explanation has already been given how to find road distances from a certain point to each point in another ...
60 views

### Copying point features along line features by predetermined distance

first post here. I searched the forum for this issue but other cases were slightly different. Anywho... I have points in a feature class. Each point has its centroid on a unique line feature in a ...
94 views

### Projection for Calculating Distances in Continental United States?

TL;DR Question: I want to calculate distance from point to edge of nearest polygon for 2,000 points in Continental United States. What is the best projection to use? Full Question: I have two ...