How to continuously plot GPS data (Lat/Long) ?
I want to feed the UI with Lat/Long data (from GPS device or file)
and plot a line/track [as at the right]
Please advice me how solve this
  Should I plot a x/y graph using the Lat/long as is ?
  Is there some ready java package/API that I can use ?
Attached are the sources for two classes I've built for dealing with lat/long values.
LatLong.java PixGrid.java
A LatLong object itself merely holds a lat/long value and has methods to convert it to various forms.
The PixGrid object is more interesting;
it maps between lat/long space and a pixel grid suitable for display.
A key feature is PixGrid's tool to map lat/longs to pixels.
To use this tool, I capture an image from GoogleEarth and note down the lat/long values for points on the image.
Then I make a table listing for each point its lat/long value
and its x,y position in the image. From this table,
the tool builds a mapping between pixel space and lat/long space.
The leastsquares routines I used are from virtualrisk.cvs.sourceforge.net/viewvc/virtualrisk/util/lma/; it is now moribund, but here's a cached copy.
PixGrid has two parts that could in separate applications. The first analyzes a table of points given both map pixel coordinates and latlong values. With a least squares fit it computes the parameters for the four equations relating pixel location to latlong. For instance, the longitude corresponding to x,y is computes by longitude = p1*x + p2*y + p3. The second part of the computation does those calculations. Between the two parts, the parameters are saved with Java's serialization support.
A more robust solution would compute an AffineTransform so image scaling could be readily supported.
For these notes I also wrote a demo program, PixGridDemo.java, to display a map and show the lat/long value for the mouse location: :
(The green border is from Window's "Steps Recorder".
I used it to capture the image with the cursor.)
