I am trying to create a simple tool that uses this website's functionality http://cat.prhlt.upv.es/mer/ which parses some strokes of text to a math formula. I noticed that they mention that it converts the input to InkML or MathML.
Now I noticed that according to this link: Tradeoff between LaTex, MathML, and XHTMLMathML in an iOS app? you can use MathJax to convert certain input to MathML.
What I need clarification/assistance with is how can I take input (say from finger strokes) or a picture and then convert it to a format in which I can provide this website from an iOS device and read the result at the top of the page. I have done everything regarding taking a picture or drawing an equation on an iPhone but I am just confused how I can take that and feed it to this site in order to get a result.
Is this possible, and if so how?
I think there's a misunderstanding here. http://cat.prhlt.upv.es/mer/ isn't an API for converting images into formulae—it's just an example demonstration of the Seshat software tool.
If you're looking to convert hand-drawn math expressions into LaTeX or MathML (which can then be pretty printed on your device), you want to compile Seshat and then feed it, not the website, your input. My answer here explains how to format input for Seshat.