convertcoordinatespython
Does anyone know of any packages out there that implement a pure python method to convert lat/long coordinates to MGRS coordinates?
PyPi has a package, but it requires some c-extensions from another source, and I didn't want to use that. I figured before I go an recreate a complicated process, I'm hoping the community can make my life a tad easier.
Thanks everyone!
You can use the GDAL Python bindings. Examples on how to use it can you find here.
For example you create points with lat/lon like this
from osgeo import ogr # first import the library
point1 = ogr.Geometry(ogr.wkbPoint)
point1.AddPoint(13.381348,52.536273) # Berlin
point2 = ogr.Geometry(ogr.wkbPoint)
point2.AddPoint(11.557617,48.136767) # Munich
Create a transformation from EPSG:4326 (lat/long) to EPSG:3035 (Projected coordinate system for Europe in meters)
inSpatialRef = osr.SpatialReference()
inSpatialRef.ImportFromEPSG(4326)
outSpatialRef = osr.SpatialReference()
outSpatialRef.ImportFromEPSG(3035)
coordTransform = osr.CoordinateTransformation(inSpatialRef, outSpatialRef)
Transform our points
point1.Transform(coordTransform)
>> POINT (4550348.379724434576929 3275002.535206703934819 0)
point2.Transform(coordTransform)
>>POINT (4436977.705661337822676 2781579.793173507787287 0)
And get the distance like this
point1.Distance(point2) # Distance in meter from Munich to Berlin
>>> 506279.480221 # roughly 506 km
Or you can create a polygon
ring = ogr.Geometry(ogr.wkbLinearRing)
ring.AddPoint(-23.378906,68.974164) # North West Corner of Europe
ring.AddPoint(-23.378906,34.307144) # South West Corner of Europe
ring.AddPoint(31.464844,34.307144) # South East Corner of Europe
ring.AddPoint(31.464844,68.974164) # North East Corner of Europe
ring.AddPoint(-23.378906,68.974164) # North West Corner of Europe (to close to polygon)
polygon = ogr.Geometry(ogr.wkbPolygon)
polygon.AddGeometry(ring) # rough bounding box around Europe
polygon.Transform(coordTransform) # transform it
And check if the polygon contains the point
polygon.Contains(point1) # Does Europe contain Berlin?
>>> True # It does ;)
And for the rest you can write functions to do what you want.
the native GPS coordinate system is WGS 84, but one should be wary that the GPS could have been configured to another Lat/long system (wrong datum induce up to 150m error). Looking at your data this is most probably lat/long in decimal degree DDD.DDDDDD for Longitude and DD.DDDDDD for latitude (need to divide both by 10e6). I assume this because you probably have the same precision in Lat and Long, and you don't need three digit for Lat ( -90 to 90) contrary to Long (-180 to 180).
EDIT: However, you should make sure that it is not DD°MM.mmmm by looking at the digits after the degree: if the value never exceed 59.9999, then it was probably DD°MM.mmmm (especially if your point is in the sea, which is not the case here) as suggested by @mkennedy
after, you can convert to Web Mercator (Google maps projection). See here for the code and here for a free converter (Tatukgis)
Best Answer
I'm the developer of the PyPI package. You could simply port the GeoTRANS code that lives in this package to Python if you want a pure-Python extension. Do you want to use this on AppEngine or something? Otherwise, a ctypes wrapper to a C extension that you don't have to worry about at all with pre-compiled versions for Windows is as good as it'll get...