How to conserve 2D lattice distances when layed onto a surface?












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Given a surface $varphi(x,y) = begin{pmatrix}x \ y \ f(x, y)end{pmatrix} in mathbb{R}^3$, where $f$ is continous (and differentiable), $x, y in mathbb{R}$, I am trying to find a map $begin{pmatrix} hat{x} \ hat{y}end{pmatrix} = Phibegin{pmatrix}x\yend{pmatrix} $ such that the distances of given points in the $x$-$y$-plane (e.g. square lattice, hexagonal lattice) are conserved when "layed" on the surface under the transformation $Phi$. By intuition, such a transformation should contract points if the surface is steep and just adopt the points from the $x$-$y$-plane where it is flat.



Does such a transformation $Phi$ exist? And can it be derived or approximated for a given function $f$?



I tried to approach this problem in 1D: for a curve $begin{pmatrix}x \ f(x)end{pmatrix}$ this can be solved by reparameterizing the curve such that it has unit speed. One can think of this as laying a chain of equidistant points onto the curve.
For the 1D case I created a Jupyter Notebook but now I am stuck on how to expand this to two dimensions.










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    $begingroup$


    Given a surface $varphi(x,y) = begin{pmatrix}x \ y \ f(x, y)end{pmatrix} in mathbb{R}^3$, where $f$ is continous (and differentiable), $x, y in mathbb{R}$, I am trying to find a map $begin{pmatrix} hat{x} \ hat{y}end{pmatrix} = Phibegin{pmatrix}x\yend{pmatrix} $ such that the distances of given points in the $x$-$y$-plane (e.g. square lattice, hexagonal lattice) are conserved when "layed" on the surface under the transformation $Phi$. By intuition, such a transformation should contract points if the surface is steep and just adopt the points from the $x$-$y$-plane where it is flat.



    Does such a transformation $Phi$ exist? And can it be derived or approximated for a given function $f$?



    I tried to approach this problem in 1D: for a curve $begin{pmatrix}x \ f(x)end{pmatrix}$ this can be solved by reparameterizing the curve such that it has unit speed. One can think of this as laying a chain of equidistant points onto the curve.
    For the 1D case I created a Jupyter Notebook but now I am stuck on how to expand this to two dimensions.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      Given a surface $varphi(x,y) = begin{pmatrix}x \ y \ f(x, y)end{pmatrix} in mathbb{R}^3$, where $f$ is continous (and differentiable), $x, y in mathbb{R}$, I am trying to find a map $begin{pmatrix} hat{x} \ hat{y}end{pmatrix} = Phibegin{pmatrix}x\yend{pmatrix} $ such that the distances of given points in the $x$-$y$-plane (e.g. square lattice, hexagonal lattice) are conserved when "layed" on the surface under the transformation $Phi$. By intuition, such a transformation should contract points if the surface is steep and just adopt the points from the $x$-$y$-plane where it is flat.



      Does such a transformation $Phi$ exist? And can it be derived or approximated for a given function $f$?



      I tried to approach this problem in 1D: for a curve $begin{pmatrix}x \ f(x)end{pmatrix}$ this can be solved by reparameterizing the curve such that it has unit speed. One can think of this as laying a chain of equidistant points onto the curve.
      For the 1D case I created a Jupyter Notebook but now I am stuck on how to expand this to two dimensions.










      share|cite|improve this question









      $endgroup$




      Given a surface $varphi(x,y) = begin{pmatrix}x \ y \ f(x, y)end{pmatrix} in mathbb{R}^3$, where $f$ is continous (and differentiable), $x, y in mathbb{R}$, I am trying to find a map $begin{pmatrix} hat{x} \ hat{y}end{pmatrix} = Phibegin{pmatrix}x\yend{pmatrix} $ such that the distances of given points in the $x$-$y$-plane (e.g. square lattice, hexagonal lattice) are conserved when "layed" on the surface under the transformation $Phi$. By intuition, such a transformation should contract points if the surface is steep and just adopt the points from the $x$-$y$-plane where it is flat.



      Does such a transformation $Phi$ exist? And can it be derived or approximated for a given function $f$?



      I tried to approach this problem in 1D: for a curve $begin{pmatrix}x \ f(x)end{pmatrix}$ this can be solved by reparameterizing the curve such that it has unit speed. One can think of this as laying a chain of equidistant points onto the curve.
      For the 1D case I created a Jupyter Notebook but now I am stuck on how to expand this to two dimensions.







      multivariable-calculus differential-geometry






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      asked Nov 28 '18 at 16:39









      tam724tam724

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