# How can I transform my coordinate's values?

Quick question:

I have a given value of a Point(x,y) with respect to one coordinate system, how can I solve the value of the same Point(x,y) but with respect to a second coordinate system?

I will be getting X within [0 -> 1000] range, I need to find its correct value within [-100 -> 100] range.

Example Point(750,SomeY):

• What is the relationship between the 2 coordinate systems? If there is a transformation that maps from the first to the second, then apply that transformation to your points. If there is not such a transformation, then I'm not sure we can answer the question. Commented Aug 3, 2016 at 19:47
• scott, my question IS to find the relationship(equation) that I need to apply on my Point in order to then transform it. To answer your question then no I don't have a relationship between both systems, yet. Expected value is 50. Commented Aug 3, 2016 at 19:50
• Your figure is the answer! The unknown $x$ is $?=50$. Commented Aug 3, 2016 at 19:57
• @EmilioNovati, this is an example that I know about. What if I have a million different points and I want the generic formula. Now this is different right? Commented Aug 3, 2016 at 19:59

## 1 Answer

If you're just focusing on $x$, it seems like a very simple transformation. You're taking $x \in [0, 1000]$ and you're trying to map it to $[-100, 100]$. If you send $0 \rightarrow -100$ and $1000 \rightarrow 100$, you can make a simple function

$f: [0, 1000] \rightarrow [-100, 100]$ where $f(x)=x/5-100$. So $f(0) = -100$ and $f(1000)=100$.

• This is it. Thank you very much :). Yes I am focusing on X but I am using the same scales for Y so it should work as it is too. Commented Aug 3, 2016 at 20:06