I am working with EPSG 27700 polygon data in PHP. All the polygons are in the UK. The polygons do not have holes inside them. I'm hoping to be able to calculate the area of these polygons. For this I believe I need to take two steps. Firstly to convert the coords into something where x an y are the same distance and then once that is done to calculate the area inside each polygon.
My naive solution would be to use some graphics package to draw the polygon onto an image and count the coloured squares.
What's a good coordinate system for this? UK Easting & Northing is my best guess.
Is there a PHP library or easily(!) implemented algorithm to find the area inside a polygon defined by a list of points?
Alternatively, should I be getting out of my comfort zone and learning to use a proper GIS system?