shapefile - What does an esri projection file represent? -
i have managed confuse myself here. trying determine associated *.prj file accompanies esri shapefile means. if have *.prj file has in it:
projcs["wgs 84 / world mercator", geogcs["wgs 84", datum["wgs_1984", spheroid["wgs 84",6378137,298.257223563, authority["epsg","7030"] ], authority["epsg","6326"] ], primem["greenwich",0, authority["epsg","8901"] ], unit["degree",0.0174532925199433, authority["epsg","9122"] ], authority["epsg","4326"] ], projection["mercator_1sp"], parameter["central_meridian",0], parameter["scale_factor",1], parameter["false_easting",0], parameter["false_northing",0], unit["metre",1, authority["epsg","9001"] ], axis["easting",east], axis["northing",north], authority["epsg","3395"] ] two things being defined in here. projected coordinate system , geographic coordinate system.
- does mean coordinates in shapefile have been calculated , if wish go geographic coordinates need use above projection variables transformation or meta data value indicating current transformed coordinate values?
i want draw shapefile using opengl need trasformation based on projection information or use coordinates read shapefile?
looking @ answer: https://gis.stackexchange.com/a/2386
it appears prj file represents current projection. each coordinate in shapefile in denoted coordinate system...
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