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What is a specific location of a place using latitude and longitude coordinates?
A place’s absolute location is its exact place on Earth, often given in terms of latitude and longitude. For example, the Empire State Building is located at 40.7 degrees north (latitude), 74 degrees west (longitude).
What data type would a longitude latitude pair of coordinates typically use in Python?
Use DECIMAL(8,6) for latitude (90 to -90 degrees) and DECIMAL(9,6) for longitude (180 to -180 degrees). 6 decimal places is fine for most applications.
Is the lat-lon absolute in a CRS?
According to a given CRS, the lat-lon is absolute (i.e. one location has one coordinate value). A CRS includes a geodetic datum which includes the ellipsoid definition, optioally a prime meridian (often defaults to Greenwich, UK – sets the origin of longitude values), angular unit (usually degrees), and axes.
Which is the default CRS for latitude and longitude?
WGS84, a CRS for latitude-longitude coordinates, is very popular on the web. This has lead to the idea that this CRS can be considered a default CRS. In fact, many specifications have done so (basic geo, GeoJSON, geosparql).
What happens if the CRS of a location is different?
The lat-lon coordinates of a location are almost always different if the CRS is different. The differences can be large–a few hundred meters–or small–centimeters. Since the coordinates are on a ellipsoid, you can’t apply Cartesian, 2D, measurements.
How are coordinates determined in GeoJSON with no CRS?
GeoJSON uses the same default as GeoSPARQL: if no CRS is specified, coordinates are assumed to be WGS84 with reversed axes. GeoJSON has a general rule that for geodetic CRSs the coordinates always have the order longitude, latitude. CRSs can be identified by a string value (so it is not possible to use designate a CRS reference as a URI).