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Thread Subject:
projection and inverse projection

Subject: projection and inverse projection

From: Terence Britton

Date: 22 Feb, 2011 17:18:04

Message: 1 of 2

Hi there, can anyone help me, im trying to perform the following and ive been told MATLAB has the capacity to do it. I am very new to MATLAB so please be as newb friendly as possible :)

1.) Read in an image to matlab using the imread() function, which is a rectangular picture of the earth (e.g http://www.trdefence.com/wp-content/uploads/2011/01/earth-in-infrared.jpg)[i can do this part]

2.) reverse (or inverse) cylindrically project the image so I reproduce the sphere it was projected from. I believe the projection in the example image for instance is either a Mercator projection or Miller projection (both members of the cylindrical subset of map projections) , so either an inverse mercator or inverse miller.

3.) lastly,project the reproduced image of the sphere onto the surface of a plane. This I believe is called an azimuthal projection.

I would be extremely grateful for any help.

Thanks Terence.

Subject: projection and inverse projection

From: TideMan

Date: 22 Feb, 2011 19:53:18

Message: 2 of 2

On Feb 23, 6:18 am, "Terence Britton"
<terence.brit...@student.manchester.ac.uk> wrote:
> Hi there, can anyone help me, im trying to perform the following and ive been told MATLAB has the capacity to do it. I am very new to MATLAB so please be as newb friendly as possible :)
>
> 1.)   Read in an image to matlab using the imread() function, which is a rectangular picture of the earth (e.ghttp://www.trdefence.com/wp-content/uploads/2011/01/earth-in-infrared...)[i can do this part]
>
> 2.) reverse (or inverse) cylindrically project the image so I reproduce the sphere it was projected from.  I believe the projection in the example image for instance is either a Mercator projection or Miller projection (both members of the cylindrical subset of map projections) , so either an inverse mercator or inverse miller.
>
> 3.) lastly,project the reproduced image of the sphere onto the surface of a plane.  This I believe is called an azimuthal projection.
>
> I would be extremely grateful for any help.  
>
> Thanks Terence.

Matlab has a mapping toolbox and there is a free toolbox for Matlab
here:
http://www.eos.ubc.ca/~rich/map.html
but it's not immediately obvious to me how you'd apply the projections
to an image.
Certainly, m_map is designed to work on vectors of latitude and
longitude, not pixels, so I guess you would have to transform pixels
into latitude, longitude first..............

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