GPS latitude and longitude coordinates converted into plane

gps android high Trask Lvge projection

A recent survey in the area of ​​GPS on Android a project, the general idea is to approximate the area of ​​the region into polygons, using GPS to get the latitude and longitude of each vertex, and then converted into latitude and longitude coordinates of the plane (BJ54, 6 degrees belt), and finally calculate polygon area. Using latitude and longitude conversion during high Trask Lvge zonation projection, namely the central meridian of each zone as the central meridian longitude and latitude band to the equator projected onto the horizontal axis, vertical axis of the central meridian of the Cartesian coordinate system. The question now is if the two were put in a different longitude, the latitude band in their not directly coordinate projection operation between the results. I think you can find distance between the coordinate value calculation is only made with the same central meridian high Trask Lvge projection transformation come, because these points are relative to the same coordinate origin. What do you think you do not know.<-! Main posts under Banner (D4) -><-! Posts under the main text (D5) ->
Reply:
All you measure longitude point averages as your central meridian.