What spatial reference should I use?
The most commonly used spatial references in web mapping are 4326 – World Geodetic System 1984 (WGS 84) and 3857 – Web Mercator. WGS 84 is the geographic coordinate system used by the Global Positioning System (GPS), which makes it one of the most commonly used spatial references.
Which projected coordinate system should I use?
Web Mercator is a common projected coordinate system designed for web mapping applications. Most of Esri’s basemaps are tiled in Web Mercator, so they can have the greatest compatibility. However, this projection does not preserve areas, distances, or angles.
What does SRID 4326 mean?
The SRID is used to tell which spatial reference system will be used to interpret each spatial object. A common SRID in use is 4326, which represents spatial data using longitude and latitude coordinates on the Earth’s surface as defined in the WGS84 standard, which is also used for the Global Positioning System (GPS).
What is the difference between UTM and WGS 84?
The difference is that WGS 84 is a geographic coordinate system, and UTM is a projected coordinate system. Geographic coordinate systems are based on a spheroid and utilize angular units (degrees).
What are the three basic spatial entities?
In the socioeconomic realm, points, lines, and areal units are the fundamental entities for representing spatial phenomena. An entity is any singular, identifiable and separate object.
Where does the WGS-84 status report come from?
The WGS-84 Status Report is based on information in the Aeronautical Information Publication (AIP) or equivalent publication of each country. Many countries include only international airport and airspace information in their AIP. The coordinates associated with domestic and military airports and airspace may not be WGS-84 compliant.
When was the WGS 84 reference frame established?
The system origin also serves as the geometric center of the WGS 84 ellipsoid, and the Z-axis serves as the rotational axis of this ellipsoid of revolution. It was established in 1987 with the intent of aligning with the Bureau International de l’Heure (BIH) Terrestrial System, also known as the BTS reference frame.
Is there a datum other than WGS-84?
There is a statement in the country AIP or equivalent publication indicating that a geodetic reference datum other than WGS-84 is used. There is no statement or an unclear statement in the country AIP or equivalent indicating the geodetic reference datum used.
What is the difference between NAD83 and WGS84?
The North American 1983 datum (NAD83) uses the Geodetic Reference System (GRS80) ellipsoid while the World Geodetic System of 1984 (WGS84) uses the WGS 84 ellipsoid. The dimensions of these ellipsoids differ slightly.