Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
I am working on a geographic project in Java.
The input are coordinates : 24.4444 N etc
Output: a PLAIN map (not round) showing the point of the coordinates.
I don’t know the algorithm to transform from coordinates to x,y on a JComponent, can somebody help me?
The map looks like this:
http://upload.wikimedia.org/wikipedia/commons/7/74/Mercator-projection.jpg
Thank you
Given your sparse example, the range of your inputs will be (90.0N – 90.0S) and (180W – 180E). It is easiest – and standard – if you convert South and West to negatives giving you latitudes of (90.0..-90.0) and longitudes of (180.0..-180.0).
Given the size of your canvas – let’s say it is 140×120 pixels – you get:
or:
where I have ordered the operations to minimize rounding error. This assumes the canvas has point (0,0) in the upper-left or, if not, that you are Australian.
Added: you just threw in the bit about Mercator projections making my simple answer incorrect (but possibly still usable by you if you don’t actually care about projection)