# Questions tagged [mathematics]

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

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### 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 ...
408 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: ...
2k 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 Calculating intersection of two Circles? These circles will ...
571 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 ...
3k 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 ...
10k views

### Converting latitude, longitude (epsg:4326) into 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 Ppython/C/C++/...
2k 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 && ...
205 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)....
972 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 ...
3k 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. ...
158 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 ...
498 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 b1,...
1k 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 ...
2k views

### Getting GPS coordinates perpendicular and parallel to AB?

I already posted a question at Stack Overflow I got the solution from @Fang but the problem is that the coordinates I need to use are GPS coordinates and apparently GPS needs a different formula than ...
234 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 ...
7k views

### Math formula for transforming from EPSG:4326 to EPSG:3857

Is there any math formula for transforming from EPSG:4326 to EPSG:3857 ? i want to implement it in php code
7k 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?
544 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 ...
140 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 ...
1k 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 ...
398 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'...
158 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 ...
906 views

### Running regression in each sample separately?

I'd like to smooth an 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 ...
2k views

### Trilateration Math Check

I'm trying to create 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 ...
1k 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 ...
345 views

### T-shaped polygons

Is there any coefficient that can indicate T-shaped polygons ? Examples of T-shaped polygons :
17k 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 ...
154 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?
2k 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 ...
10k 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 ...
392 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 (Encyclopaedia Britannica) and georeferencing it using QGIS 2.0.1, I get really accurate georeference solution using polynomial 2 transformation: ...
655 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 ...
4k views

### Detecting invalid polygons (self-intersecting or touching)

An invalid polygon can be defined as one that intersects itself, or one where the lines make contact, ie, the two shapes at the top of this picture. Given the XYPoints of a polygon, what logic (...
199 views

### Math related sum distance problem with TSP content

I hava an interesting problem related with GIS / MATH / TSP. If I calculate the distance between A and B on a x/y-style coordinate system it is obvious to use the following formula: sqrt((Ax-Bx)^2+(...
564 views

### Find items within a Bounding Box

Not 100% sure if this is the correct place to ask my question so I apologise if it isn't. Also, I have very limited experience with GIS systems, so please pardon my ignorance if some of my terminology ...
343 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?
2k views

### How to sum or even perform more complex mathematical operations (multiply, add a constant, ...) two GDAL grids?

I have two grids with same cell size, same starting position (top left) and same grid size. I want to sum the grids and create a sum grid as an result: e.g. grid A + grid B = grid C How can I ...
3k views

### Calculating mean slope: Harmonic or Arithmetic Mean?

I have to calculate the average upslope percent slope for a large dataset, the basic method is detailed here. However, I've begun to wonder if harmonic mean might be more appropriate than the ...
4k views

### Drawing Ellipse with OpenLayers

I am trying to draw ellipse on the client side using openlayers with some mathematical functions from drawing ellipse with svg. I have achieved drawing it but not rotation what I have written for ...
11k views

### Calculating intersection of two 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. For example, given: Lat/Lon ...
2k 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 ...
2k views

### Find the nearest point on a line

I have a line that exists between two latlon positions, and a point on a certain latlon position. What I want to know is what the nearest point on that line is (in respect to the other point). So a ...
2k views

### How to place markers on the outline of a circle in google maps?

I have the center of a circle and it's radius and I need to place variable amount of markers on the outline/stroke of the circle. The distance between this markers should kept same, so if I have 8 ...
510 views

### Proper use of Modulus "%" operator in ArcMap [closed]

Objective: Gather pour points to define a specific-sized watershed. In this case, 1000 pixels. (for this thought exercise, watershed is to mean any point that flows through a pour point, regardless of ...
4k 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 ...
704 views

### Recreating A Lat/Long Grid Using a Specified Formula

I'm trying to recreate the Gridded Mercury emissions 2000 (0.5 x 0.5 degree grid) designed by the Arctic Monitoring and Assessment Programme. The file is in ASCII format, but without any coordinates. ...
9k views

### How to find a point half way between two other points?

I'm working on implementing the OSM Mobile Binary format for map data, and because it uses a 16 bit delta for each point along a way, it cannot represent a way if there is a large distance between two ...
243 views

### Math module VS PostGIS

I have a simple (and maybe stupid) question for you today. I have to compute intersection points between GIS polygons and imaginary lines I draw thanks to a script of mine... And I wonder if it would ...