Spherical geometry is the geometry of the two-dimensional surface of a sphere.

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Moving object of fixed dimension without distortion

I am trying to move a polygon object in a shapefile to a new location. I will perform an offset so that the process can be automated by shifting the object to a new geographic coordinate or moved by ...
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0answers
28 views

How do I convert Lon and Lat to pixels in map using world file?

I have a tiff map file, with a tfw world file that has these parameters (lon/lat in radians): 0.00000107180145766 \\ A 0.0000000000 \\ D -0.0000000000 \\ B -0.0000009331315579 \\ E ...
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1answer
159 views

Mercator bias plot in Leaflet

I was inspired by this wikipedia image from the mercator projections page to hack around with leaflet. The idea was to interactively have your cursor move a continent and that it would be corrected ...
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1answer
512 views

Specifying a rectangle as two latitude/longitude pairs, one for center and one for size

I am trying to make sense of the Google S2 library for spherical math (it works like this). I need to get a rectangle for searching for nearby entities in a database, based on a point and a distance ...
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5answers
8k 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 ...
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3answers
1k views

How to calculate the intersection of 2 Circles?

I'm trying to figure out how to mathematically derive the common points of two intersecting circles on earth's surface given a center Lat/Lon and a radius for each point. Ex. Given: Lat/Lon ...
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2answers
39 views

Spherical law of cosine what does the 'a' represent?

I want to use the spherical law of cosine formula, θ = atan2( sin Δλ ⋅ cos φ2 , cos φ1 ⋅ sin φ2 − sin φ1 ⋅ cos φ2 ⋅ cos Δλ ), to calculate distances between coordinates, but, I cannot for the life ...
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0answers
32 views

Pont to Point and Point to Line Calculations [duplicate]

We have been beeating our head against a wall trying to get point to point and point to line segment (perpindicular) to work in PHP. I posted the other day as well but did not include the code in ...
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38 views

Point to Line Calculations

We are looking to take a point and compare it against the nearest point to an adjacent line. All values are in lat/long. We tried using some of the concept found on the board but found it did not ...
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0answers
18 views

Find coordinate of point on the boundary of a circle given a latitude/longitude and radius [duplicate]

I understand how to use the haversine formula to compute the distance between two points on the earth. However, I would like to answer a similar, albeit different question. How can I compute the ...
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0answers
24 views

Find square with latitude and longitude for given lat and lng and distance [duplicate]

I have the coordinates of some point, lets say lat and lng, I want to find the latitude and longitude of top left and bottom right corners of the square, whose sides are located k kilometers from the ...
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2answers
82 views

How to find the destination point given a start point, distance and bearing?

If I have a starting point as well as distance and a bearing to the destination point, how can I find the coordinates of the destination point using PostGIS? I'm looking for a PostGIS equivalent to ...
3
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0answers
63 views

Given distances from two locations how to accurately find geographic coordinates [duplicate]

I am working on a research problem which requires me to calculate a geographic location accurately (with error distance of few meters), given distances from two geographic locations. For instance: ...
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1answer
110 views

Converting Lambert Conformal (x, y) of spheroid to (lon, lat) of NAD83 with proj/cs2cs?

Revised Trial: Correct? According to Andre Joost advice, I tried with "+towgs84=0,0,0", and the both two ways seem to get the same answer that mkennedy posted below. So, just to make sure, anybody ...
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0answers
50 views

Compute visibility graph on sphere

I have a PostGIS table with some polygons (stored using the geography data type). They represent regions on a spherical earth. For each pair of vertices chosen from among all the polygons, I want to ...
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2answers
173 views

Given a flight path given in latitudes and longitudes, how do I find another flight path that is parallel to the path given?

Given a flight route that is given in latitudes and longitudes, how do I find another route that is "parallel" to the route given (find a perpendicular line to each waypoint given)? I think the best ...
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2answers
85 views

Is there an average size for British postcodes?

Is there an average size for British postcodes? Or a method of determining the size for a particular British postcode? Thanks. Considering creating a related program and this would be valuable ...
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0answers
28 views

Quickest method for determining which postcode is 2 miles north of original postcode? [duplicate]

What is the Quickest method for determining which postcode is 2 miles north of original postcode? For instant L17. I know how to determine the distance between 2 points as below, but the above ...
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1answer
44 views

Hard to get my head around, generating average price for houses in each quadrant

I'm able to determine the average price of houses sold in a particular area (like the squares on image below) dependent upon postcode. Although I can generate the average sale price for a particular ...
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1answer
53 views

How do I convert OS coordinates (X and Y) to longitude and latitude coordinates?

How do I convert OS coordinates (X and Y) - Eastings and Northings to longitude and latitude coordinates? For example X and Y below X (Eastings): 347904 Y (Northings): 287484
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1answer
87 views

How do I figure out the grid references (Eastings and Northings) necessary to create a circular 1 mile radius around one location?

How do I figure out the grid references necessary to create a circular 1 mile radius around one location? For instance: Grid Reference: SO 47904 87484 X (Eastings): 347904 Y (Northings): 287484 ...
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1answer
84 views

Defining a line from geographic coordinate points.

On a flat surface we can define any point on line which passes from point1 (x1,y1) to point2 (x2,y2) via simple trigonometry. How can we do that with latitude and longitude of 2 points? Imagine we ...
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1answer
124 views

How do I figure out the longitude and latitude coordinates necessary to create a circular 1 mile radius around one location?

How do I figure out the longitude and latitude coordinates necessary to create a circular 1 mile radius around one location? I don't mind how many coordinates that takes. For instance: Latitude = ...
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4answers
859 views

How to calculate the visible sky percentage

Hi I am writing a project and I am stuck: can anyone explain as simply as possible how to calculate the visible sky percentage? I have done a satellite survey and have worked out the height of ...
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0answers
75 views

Intersection between a ray from lat, lon, alt, with pan, tilt and earth's surface

I have a problem that consists of finding the intersection point between a ray from a given lat, lon, alt, that is looking to a given pan and tilt angles and the earth's surface. I need the lat, lon ...
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0answers
39 views

recalculate latitude and longitude from a pixel in a cropped map

i want to recalculate a geographic coordinate from a pixel in a map. For this i have the size and the coordinates from the map to convert a coordinate to a pixel is use the algorithm, you find at ...
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3answers
434 views

How to compute distance between 4500 points fast?

I am working on a location problem with 150 customers (points) and 30 facilities (points). I have determined the location of any customer and facility by google earth and then saved them in a KMZ ...
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0answers
113 views

How to approximate point to segment distance on sphere?

I would like to approximate the distance of a line segment from a reference point on the map (coordinates are gives as lat/lon). In the Cartesian coordinate system I would simply find the closest ...
2
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3answers
1k views

Local Coordinate to Geocentric

The ultimate question, I need a transformation matrix to take a point in local space representing a roughly 500m x 500m place in New Mexico centered at -108.619987456 long 36.234600064 lat. The final ...
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0answers
158 views

Feature.geometry.transform not working

// World Geodetic System 1984 projection var WGS84 = new OpenLayers.Projection("EPSG:4326"); // WGS84 Google Mercator projection var WGS84_google_mercator = new ...
3
votes
3answers
293 views

Formula for coordinates (lat, lon), azimuth and distance.

I would like to know how to find a set of coordinates on a small circle some distance from another point. For example, lets say A = (39.73, -104.98) #Denver B = (39.83, -106.06) #point ...
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2answers
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How accurate is approximating the Earth as a 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 ...
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1answer
702 views

Line intersection with circle on a sphere (globe or earth)

How can I find the intersection point of a line and a circle on a sphere (on earth) Please, if any one knows a good solution help. Thanks in response :)
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2answers
235 views

Variation of algorithms to find point from another point with bearing and distance

There are several algorithms to calculate distance between two latitude/longitude points. Haversine Hubeny Lambert-Andoyer Vincenty's formulae for inverse problem But there are not so many ...
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1answer
123 views

Rhumb lines intersection

I looking for algorithm how to find out whether two rhumb lines given by point1 with azimuth1 and point2 with azimuth2 have intersecting point. Have anyone idea how to find intersection ? For ...
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1answer
88 views

How to get screen coordinate from geographic one?

I need to know, how can I convert some geographic coordinates to the screen one. I want to remind you about desktop coordinates system, how it look like: I've developed soft, which is loading map ...
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0answers
81 views

How can I convert LIDAR based measurement to UTM coordinate?

I have lidar based measurement with azimuth elevation and range, I would like to convert this data to UTM coordinate. I know the position of the lidar in UTM coordinate system, so I developed the ...
2
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1answer
122 views

Does spherical equilateral triangle T contain point P?

I am working on a Python script to: compute the vertex coordinates of a geodesic sphere/icosahedron, project the triangles onto a sphere, then find which spherical triangle contains an arbitrary ...
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0answers
182 views

Locating the centroid (center of mass) of spherical polygons

I'm trying to work out how best to locate the centroid of an arbitrary shape draped over a unit sphere, with the input being ordered (clockwise or anti-cw) vertices for the shape boundary. The density ...
3
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2answers
207 views

Is there a world projection that looks like a 3D globe?

I would like to try and show data such that it appears as if it was on google earth. For example, in this case, the view of the earth is circular-like and the data shown curves around. Are there any ...
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2answers
4k views

How to convert Distance, Azimuth, Dip to XYZ?

I have an excel spreadsheet with header and survey drill data. Header data contains hole ID, and location coordinates, and the survey data contains related downhole survey with Distance, Azimuth and ...
2
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1answer
227 views

Map projection lat, lon to pixel?

I'm trying to find the concave hull of a lat, lon pointset but when I project my points on my map it doesn't look like expected. I've tried a lineare projection and a spherical projection. My data is ...
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1answer
552 views

Transform regular lat/lon to rotated lat/lon

I am currently working with climate data projected in a rotated lat/lon grid and came across this excellent 'cookbook' by mkadunc on how to manually transform rotated lat/lon to regular lat/lon: ...
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3answers
3k views

Lon/lat transformation

First I should clarify I don't have previous experience with the field, so I don't know the technical terminology. My question is as follows: I have two weather datasets: The first one has the ...
2
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1answer
97 views

Draw a line and a buffer around it onto the spheroid

I need to draw a line between two points and create a buffer around this line. The only difficulty is that I need to draw not a "cartesian" line but a line that is laying on the spheroid. I tried to ...
2
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0answers
52 views

How can I figure out whether a sphere is intersecting the Earth between a given lon/lat range?

Given a lon/lat range that represents a tile on the Earth's surface, I need a computationally efficient way to figure out if a spherical volume defined by a point (assume ECEF coordinates) and a ...
2
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0answers
197 views

Specifying a bounding rectangle using Google's S2 package for spherical geometry [duplicate]

This is my first post on GIS, I hope it is not too trivial a question. I work on a project on Google AppEngine, which is backed by a NoSQL datastore. This makes a proximity filter different from ...
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0answers
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Finding the exact coordinates of circle's extreme east and west points on a sphere [duplicate]

I'm currently implementing the Bentley-Ottman algorithm applied to spheres, involving intersections of many spheres on one sphere, circles in most cases of course. This requires locating "event" ...
2
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0answers
94 views

Find arc endpoint with bearing and radius counting with curvature of the earth?

So my problem is that I have start point [lat,long] for arch, bearing, radius and I need compute end point [lat,long] ? End point should be in 180 degrees angle from start point and I should be aware ...
4
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1answer
73 views

What information is needed to determine the section of the earth's surface visible in a photograph?

What information (either provided by a user or taken from sensor readings) would be required to determine the geographic area encompassed by a photograph? It seems like the area visible from a ...