Thus Arthur’s Seat, an extinct volcano in the centre of Edinburgh, has a BNG grid reference of NT2755072950. People working in the UK may have to go through another step to convert their data into the British National Grid format (BNG), which uses two-letter codes to define 100km-wide square regions instead of presenting the full 13-figure coordinates. Taking things even further, see the following of how to do GIS analysis using only Python with the Geopandas library: British National Grid and the OSGB36 datum. Python can do maps, too check out the Cartopy, Fiona and Shapely libraries. If you are playing with coordinate transforms, then it is likely that at some point you are going to want plot stuff on a map. # įor other systems, check out the pyproj website. Xx, yy = ansform(wgs84, isn2004, lat, lon) Coordinate system changes are done with the transform function. This is even the case with GPS or GoogleEarth data, which use the specific WGS84 datum. In most cases, you will want to change between coordinate systems. 2.) Changing between different coordinate systems Note: older versions of pyproj use pyproj.Proj("+init=EPSG:4326") syntax and return coordinates in lon, lat order. UTM27N=pyproj.CRS("EPSG:32627") # UTM coords, zone 27N, WGS84 datum UTM26N=pyproj.CRS("EPSG:32626") # UTM coords, zone 26N, WGS84 datum Osgb36=pyproj.CRS("EPSG:27700") # UK Ordnance Survey, 1936 datum Wgs84=pyproj.CRS("EPSG:4326") # LatLon with WGS84 datum used by GPS units and Google Earth # Define some common projections using EPSG codes # Define a projection with Proj4 notation, in this case an Icelandic grid These are called EPSG codes and can be looked up on. These can be defined using the Proj notation (see Proj4 documentation for details) but it is easier to set up commonly-used projections by referring to their standard code numbers. The first step is to define pyproj ‘objects’ to represent the coordinate systems that you want to use. Pyproj can be installed via the pip package manager ( pip install pyproj). I had been using both for a while but only recently discovered the pyproj module that performs coordinate transformations inside Python itself. Both are open source, so you are free to install them on as many computers as you want and to share them with your friends. The Proj4 libraries are a set of programs for performing coordinate system transformations. Python is an easy-to-use programming language which, thanks to a growing number of cool extension modules, is really taking off in the world of scientific data handling.
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