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0
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1answer
51 views

Why does a transform from polar coordinates using `TransformedField` not agree with by-hand calculation?

I have the following (simple) system of ODE's that I wish to express in Cartesian coordinates: \begin{align*} r' &= r(1-r)\\ \theta' &= 1 \end{align*} Working it out by hand, by ...
19
votes
1answer
504 views

Analogue for Maple's dchange - change of variables in differential expressions

Maple owns an interesting function called dchange which can change the variables of differential equations, but there seems to be no such function in Mathematica. ...
4
votes
3answers
163 views

Translating Histogram

SeedRandom[1]; RandomVariate[NormalDistribution[], 100]; Histogram[%, Automatic, "Probability"] The above code produces a histogram like I want to translate ...
1
vote
1answer
72 views

Plot a parametric equation in cylindrical coordinates

I'm looking for a way to plot this parametric equation on cylindrical coordinates. r = e^t theta = t+1 z = e^2t Any help would be appreciated
0
votes
1answer
49 views

Change of variables—Galilean transformation

I have a function of two variables, f[x, y], and I wish to do a Galilean transformation, i.e., y = z - v t, where ...
1
vote
1answer
91 views

Is there an easy way to transform unit vectors from spherical to Cartesian coordinates? [duplicate]

Is there a built-in function on Mathematica that will transform unit vectors from one coordinate system to another? I have a vector expressed in spherical coordinates, and I would like to find the ...
10
votes
1answer
204 views

How can I define or use a new coordinate system in Mathematica?

I want to use the dipole coordinate system as defined in this paper: http://arxiv.org/abs/physics/0606044 I see that Mathematica can do all kinds of vector analysis using different kinds of ...
0
votes
0answers
76 views

Von Neumann's method to generate points uniformly distributed on a region of a n-sphere surface

I am trying to generate points uniformly distributed on a region of a single n-sphere surface (all angles in hyperspheric coordinates are between 0 and Pi/2). I decided to use von Neumann's method ...
6
votes
2answers
162 views

How can I output the coordinates of a city in coordinates of the Mercator projection?

On Mathematica version 8, I would like to use CountryData and CityData to mark Paris on a polygon map of France in the Mercator ...
2
votes
1answer
55 views

How to apply a transformation to a grid?

I would like to apply a coordinate transformation, visualised as an action on a two-dimensional grid like The particular example above is $$x^\mu \mapsto \frac{x^\mu - b^\mu x^2}{1-b\cdot x+ b^2 ...
1
vote
1answer
108 views

Astronomy: Transform coordinates from horizon to equatorial

I'm using Mathematica 10. Giving a longitude & latitude on Earth, giving a local time, how can I transform Horizon Coordinte (az , alt) to Equatorial Coordinate (RA , DEC). Use function so I can ...
0
votes
0answers
35 views

coordinate system problem [duplicate]

I had an issue about the coordinate system of mathematica. I have a {800,600} image acquired with a camera. The projection matrix P of the camera is calculated using the calibration task. Now, when I ...
3
votes
0answers
93 views

My code does not give the same results on mathematica 9 and 10 [closed]

I have developed last year an algorithm using mathematica 9. In this algorithm, I remember that coordinate system of Image and Graphics are not the same. However, in mathematica 10 the coordinate ...
3
votes
2answers
164 views

Different between two graph in the Polar Plane

How can I plot $\theta=\cos r$ in polar plane? Of course I know that is different with $r=\cos \theta.$
1
vote
1answer
144 views

Plotting in Elliptical coordinate system

I want to plot an equation in elliptical coordinates. In the traditional elliptical system, Ellipse and hyperbola shares the same confocal point. Is there a plot function that draws a function in this ...
1
vote
1answer
88 views

CoordinateTransformData (cartesian to spherical)

I am using Mathematica v9.0.1.0 and wanted to compare Mathematica's CoordinateTransformData command to Matlab's cart2sph. (Note ...
10
votes
1answer
259 views

Compose many Geometric Transformations for 3D Graphics

I'm struggling to understand what would be a good way to compose several geometrical transformations to create a single TransformationFunction to be applied to a ...
0
votes
1answer
190 views

Order contour points in clockwise

I want to describe shape of an object using contour points descriptor. Given a silhouette (image black white of an object), I extrait the contour points using EdgeDetect[] fonction. After that, I need ...
6
votes
2answers
509 views

Find a right angled triangle

If I am given 10 points in the coordinate system in the for (x,y); where x is the x-coordinate and ...
-1
votes
1answer
87 views

Similarity of two plot to each other [closed]

I want get the similarity of two different plot by Percent ... I have many plots for comparison like below : y : ...
4
votes
1answer
107 views

Convert Locator (x,y) values to Lat/Lon as per GetCoordinates on Map

I want to convert the (x,y) coordinates you get from using a locator on a map to Lat/Lon coordinates - exactly like the GetCoordinates tool does when you right click on a map. ...
3
votes
0answers
174 views

Derivatives with respect to Cartesian coordinates of functions in spherical coordinates

This seems to me to be a common task, and the more surprised I was to not have found much on this. Suppose I have an expression f in spherical coordinates ...
8
votes
1answer
335 views

ImageTransformation: polar to cartesian

I am working on something that requires the polar transformation of some images. I implemented this transformation with ImageTransformation: ...
7
votes
2answers
478 views

Mapping data on Archimedes' spiral

I would like to map my data on Archimedes' spiral and preserve the distance between points on the curve. The test data consists of 20 evenly spaced {x,y} ...
1
vote
1answer
206 views

Using spherical derivatives with NDSolve

I am trying to plot the path of an object around a centre of mass. Obviously this needs spherical coordinates. The problem I encounter is with the derivatives. The Derivatives in spherical coordinates ...
2
votes
1answer
146 views

Plotting in projective space

I am having difficulty figuring out how to plot to projective space. Suppose I have a region which I have plotted such as: ...
0
votes
0answers
81 views

Geometric Transformation not working - degenerate points?

I've successfully used FindGeometricTransformation to project the simplex triangle onto the x-y plane: ...
1
vote
2answers
99 views

What is the 'Mathematica-way' to test a variable transform?

Hello Mathematica experts. I would like to play around with a simple variable transformation, to test some claims about it. I wonder if there is a Mathematica-like way to do this. The specific case ...
1
vote
0answers
122 views

How to construct a coordinate system that owns detailed calibration in the 3D enviroment?

Recently,I write a program to demonstrate the forward kinematics of the SCARA robot.The code showed as below: Using this function to construct the BigArm and ...
1
vote
2answers
499 views

How to make Mathematica use the chain rule?

Lets say I have the following PDE: $$x^2 u_{xx} - u_{yy} + u_y = 0$$ And I have the following change of variables: $$ s(x,y) = x e^y \, \, \, , \, \, t(x,y) = x e^{-y}$$ How can I use Mathematica ...
5
votes
1answer
362 views
0
votes
0answers
100 views

How to make MousePosition be referenced by a coordinate system established over an image?

In the question of How to make a curve selectable from a scaned image and convert it to a list of coordinates, thanks to the excellent answer of Alexei Boulbitch, I knew how to select a series of ...
2
votes
1answer
678 views

Time derivative of unit vector in spherical coordinates

Is it possible to take a time derivative of a vector given in some curvelinear coordinate system (i.e. spherical)? Mathematica would need to take into account the time dependence of the basis vectors. ...
1
vote
1answer
86 views

CoordinateTransformData that works for any dimension

The function CoordinateTransformData in Mathematica only works for three dimension. For example, ...
4
votes
1answer
285 views

Plot a cone in spherical co-ordinates

As we all know in spherical coordinates a function phi = π/3 gives us a cone. The cone makes an angle of π/3 with the imagined ...