# Tagged Questions

The abstract study of topics encompassing quantity, structure, space, change, and other properties

620 views

### How to calculate the center and radius of a circle based on points

I have a set of lat/long points. I need to calculate the center point and radius of a circle that will encompass all the points. The co-ordinate system used is latitude/longitude as per google maps. ...
379 views

### Finding Intersection of Two Circle given Lat/Lon and radius?

I am attempting to calculate the intersection of two circle on the Earth with a given latitude, longitude and radius. I started with this How to calculate the intersection of 2 Circles? These circles ...
370 views

### Check if a point coordinate is between linestring coordinates

I know that, linestring is a vector and if i want to check that, if point coordinates are between linestring beginning and ending coordinates then i need to use vector comparison (x2 > x && ...
2k views

### Doing Math calculations within ArcMap Dynamic Text?

Is it posssible to perform any math on ESRI ArcMap dynamic text? For example I have the area of a SDE park layer's SHAPE.AREA, but it is in m2 because the layer is in NAD_1983_UTM_Zone_17N. I want ...
1k views

### Calculating angle of polyline at midpoint using Python/ArcPy?

Trying to calculate the angle of a line at its mid point using python; this will be used to display flow direction on a water network. I've developed this script, which works in terms of generating ...
718 views

### How to convert latitude, longitude to EPSG 3857?

I'm looking to study the math involved to see how a given latitude and longitude in decimal degrees can be converted to epsg 3857. Can anybody point to a good reference or a possible python/c/c++/java ...
26 views

### How to resolve a rectangle with know points? [closed]

How do I find the coordinates(lat, lon) for D and E in the following rectangle? I know: A (lat, lon) B (lat, lon) C (lat, lon) AE, BE, AC
5k 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 (37....
36 views

### Finding GeoTIFF GeoTransform when camera position is known

In short, I want to create a GeoTIFF from aerial images taken with a camera whose position (x, y, z, roll, pitch, yaw) and parameters (focal length etc.) are known. No ground control points are known. ...
76 views

### Bearing to X,Y, Z

I’m working on a small project where I’m testing the ability of a laser to accurately measure the angle of a wire. My control for the experiment gives me X,Y,Z coordinates for a point on the wire and ...
61 views

### Calculate location on line with known azimuth to point

I have the following situation (consider distances up to 300m - without great circle etc. affects): How can I calculate the unknown location when I have all other locations in the triangle and ...
97 views

### How to generate missing points in GPS trajectories?

I have some GPS trajectories that include gps locations recorded on variable frequencies (every 1 min ,5 min , 20 min,etc.)using a geographic projection WGS84. In my work, i need a fine-grained GPS ...
31 views

### calculate turning acceleration from a compass

I have degree and timestamp and want to calculate the turning acceleration. What to trigger if the compass is turning fast. Is there a mathematic way to get an acceleration parameter?
181 views

### Understanding location storage and query algorithms?

One of the most important aspects of a GIS-equipped database is that it provides the user with the capability to quickly query for all points within some arbitrary geographic area that match some ...
349 views

### Distance with Bearing Calculation not working

I have this function in Python that calculate distance from a point with bearing. Problem is the latitude part is generating the wrong answer and i cannot figure out where i went wrong: def ...
28 views

### Determining North-South Line Via Watch Method?

I read about Determining North-South Line Via Watch Method recently (page 9). What is the underlying geometric/celestial reason this works? What is the error to true north given this method? Is ...
43 views

### Arithmetics with Coordinates [duplicate]

I wonder if I can do simple arithmetics with coordinates. Can I do substraction of coordinates like 2.570801 (lng) 46.89023 (lat) / 17.424316 (lng) 55.15377 (lat)?! Or will that get messy without a ...
99 views

### Index express the similarity in shape between two data sets

I have two data sets. One is points in the blue curve. The other is points in the green curve. Now I want to find a property (P) or something else like index that has the following characteristics: ...
93 views

### What mathematical processes does a GPS receiver use to determine position?

I'm writing a report on the mathematics of GPS, but I'm wondering what methods the GPS actually uses. What I've done is set up the four sphere equations and solve them using the Newton-Raphson method ...
373 views

### Project location on a (great circle) path

I've been searching this SE site for quite a few hours now, and I'm still struggling to find a solution to my question. My goal is that given a way in OSM and my location (lat/lon coordinates), I want ...
2k views

### How to “calculate” distance-to-ground of all 18 OSM zoom levels?

Assuming I'm building a 3D solution with the "world" being mapped to global geo-data supplied by OSM / Cloudmade... think http://www.webglearth.com but with completely different goals and use-cases. ...
36 views

### how do calculate nearest point in earth map with coords

I am having trouble calculating nearest point for another point with earth coordinates. I am particularly interested in calculating the intersection of linestring vector with earth coordinates. I'm ...
307 views

### Aerial photogrammetry book with all the math

Can anyone recommend a book that hits all the math for the general situation of doing serious photogrammetry calculations on aerial photographs? Particularly an inexpensive book or one I can get ...
63 views

### How do I compute uncertainties in the positions transformed using Helmert transformation?

I am familiar with Python, MATLAB and Mathematica. My data is given by Cartesian coordinates (positions in X,Y,Z (meters), standard deviations XX, YY, ZZ (meters) and a correlation matrix (XY, YZ, ZX)....
56 views

### How to organize/cluster nodes moving on the same direction

The Problem I am working on a problem of clustering for mobile nodes. Initially, I though of clustering the nodes based on their angle of movement (relative to the x-axis). However this situation ...
114 views

### Comparing compass bearings

I have several compass bearings: bTrue = 190° b1 = 250° b2 = 100° b3 = 170° b4 = 90° I want to compare b1 - b4 and find out how close they are to bTrue. So bTrue is 100%. How much percent is then ...
85 views

### Is there a method to tell which hemisphere a point belongs to, in WGS84 geoid, where the equator is an arbitrary ellipsis?

I use the WGS84 geoid (because I'm working with a GPS chip). I define an ellipsis that splits the surface in two parts, lets name these 'A' and 'B'. This ellipsis is defined by two points 'a' and 'b'...
106 views

### mathematics of spatial diffusion models

There are different types of spatial diffusion such as contagious model, migration model, etc. What are the good books to learn about the mathematics behind these spatial diffusion models?
269 views

### Getting GPS coordinates perpendicular and parallel to AB

I already posted this question here And I got the solution thanks to Fang but the problem is that the coordinates I need to use are GPS coordinates and apparently GPS needs a different formula than ...
100 views

### Convert Raster into Cell by Cell Table

I'm hoping to run some Python mathematics on a raster, outside of ArcGIS. It's important to have a cell by cell table for the analysis I want to run. I plan to store it in a python dictionary similar ...
395 views

### How to take cosine squared of raster using python

I have an equation y = cos^2(x) where x is a raster. How can I write this equation in python?
353 views

### Comparing two maps with two different libraries

I'm currently making a demonstration to compare the two OpenLayers libraries (2 and 3). For doing this, I have made two div elements and put the different maps on each other. The goal is to make a map ...
77 views

### Formula for charting a course around the globe, given a location and degree heading?

I'm looking for a formula that takes a long/lat coordinate and a degree heading, (e.g. "I'm standing in San Francisco and I'm facing 45º from north"), and which can draw a line across a map projecting ...
128 views

### Finding the shortest distance between a point and a line

I read and understood the following GIS question and the accepted answer, calculating-the-distance-between-a-point-and-a-virtual-line-of-two-lat-lngs I can return the value in the ShortestLength ...
4k views

### Calculating the distance between a point and a virtual line of two lat/lngs

Please refer to the example and corresponding image. I would like to achieve the following: provide two locations (lat/lng), which are shown below as A and B. From this, a virtual line would be drawn ...
89 views

### How can i add script with math functions to model builder?

I am very new to model builder + python. (Sorry for my english too) I am trying to make a model. Don't know if it matters to upload it. If you want i can. I want to calculate variance from a points-...
36 views

### Calculate end point Height above the MSL of the target point given a starting point, distance, azimuth and elevation [duplicate]

We need to find the end point height (from the earth surface) given the start point lat, lon, azimuth (270 deg), distance (500 km) and elevation above the horizon of start point (10 deg). The ...
27 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 ...
409 views

### Do I need to run regression in each samples separately?

I'd like to do smooth NDVI image by regression analysis; response of time series NDVI image to Julian date to represent the seasonal changes in NDVI as a function of Julian day. The time series NDVI ...
51 views

### Calculating raster values from center to edges to represent normal distribution

Edit for simplification/clarification: What I want to do is take a raster and calculate cell values from center to edges such that the center has an arbitrarily determined high value which decreases ...
924 views

### Trilateration Math Check

I'm trying to crate an indoor trilateration program working off of N BLE objects. Where I have any number of beacons in a room and my ipad can track its location within them to a sub meter degree of ...
624 views

### Trilateration issue

My program isn't making use of any geographical data, but I'm hoping that the users experience in the subject can help me with my current issue. The project I am working is trying to locate a user in ...
208 views

### T-shaped polygons

Is there any coefficient that can indicate T-shaped polygons ? Examples of T-shaped polygons :
3k views

### What formula is used for distance between 2 points in Google Maps?

What formula is used by Google Maps for calculating the shortest distance between 2 points (having their Lat, Lng coordinates)? Is it purely based on Haversine? Or is it something different? Is there ...
245 views

### Is it possible to solve Differential Equations in ArcMap and/or ERDAS Imagine?

I would like to know if it is possible to solve differential equations and run them directly in either ArcMap or ERDAS Imagine, similar to the raster calculator in ArcMap?
490 views

### How to determine vector between two lat/lon points

For all the math geniuses out there...given two lat/lon points (point A and point B), what is the simplest way to find the vector needed to reach point B from point A. For example, the vector needed ...
231 views

### What are the set of projections that can be accurately georeferenced using polynomial 2?

Background I'm starting with a map from the internet (Encyclopedia Britannica) and georeferencing it using QGIS 2.0.1, I get really accurate georeference solution using polynomial 2 transformation: ...
221 views

### How to locate a house on the 3D Map correctly?

I've done my 3D map generation in WebGL/THREE.JS project and have an issue with the building locations. I have the data about building position ( its polygon ) from DB server, but first of all I want ...