proj4.defs("EPSG:27700","+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +towgs84=535.948,-31.357,665.16,0.15,0.247,0.998,-21.689 +units=m +no_defs +type=crs");