converting my WGS 84 co-ordinates into screen x and y

I am stuck on a little problem of creating a simple map app. what i am trying to learn is the mathematics behind the conversion of my WGS 84 GPS co-ordinates.

this is the problem:

I have two WGS 84 co-ordinates; lat:53.7506 Long:-2.3931 + lat:53.7638 Long:-2.4212 I want to convert these values onto points on my screen x = 'a' value between 0 and 200 and y = 'a' value between 0 and 200

i have said a value as this value will be derived from the lat and long figures as mentioned above.

can anyone help please?

i have tried normalising the figures using the formula N = V/D (N being the normailsed value with V being the co-ordinate value and D being the max value of the screen area which in my case is 200. this didnt work as all the figures generated was all in the 199 - 200 range but I have gotten lost with the thought process on this now so I need some help.

I a开发者_高级运维m sure there is a formula for calculating the right but i cannot seem to find it

please help as I need to sleep well tonight :)

thanks

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It is a simple linear mapping for x, and one for y with a twist:

x) as the lower limit is the left hand side, you can simply use

x = (long + 180)/360 * x_max

y) as long 0 is in the middle, you'll need to substract/add accordingly:

y = (y_max/2) - (lat/90) * (y_max/2)