Is it safe to use ray casting algorithm to check if a coordinate is inside a polygon specified as coordinates? Purpose of my question is because the longitudes are not parallel in a Cartesian sense, so is that a problem? If so, how big of a problem is it (for how big polygons it can matter for example), and how can I correct it? For example, can I map lat/lon to another domain and use ray casting safely?
I don't know much about GIS, but willing to learn anything related to my question.