topic Re: Coordinate System and converion in Coordinate Reference Systems Questions

Coordinate System and converion

rajujee — Tue, 28 Apr 2020 12:40:49 GMT

Hi,

I need guidance, tips to understand, translate coordinate system. I am using an internal asset management system that is keeping coordinate (x, y) as -8889118.673429, 5342798.016983. It is located in Hamilton ON.

Any idea what type

How I can compare with coordinate system WGS 84?

Thanks a bunch

Re: Coordinate System and converion

BojanŠavrič — Tue, 28 Apr 2020 16:37:49 GMT

raju vayu, coordinates of your point are probably in Projected Coordinate System called WGS 1984 Web Mercator (auxiliary sphere), WKID 3857. They are projected with Mercator Auxiliary Sphere projection from latitude and longitude values defined in Geographic Coordinate System WGS 1984, WKID 4326. If you project those values back to geographic coordinates, you would have much smaller numbers, roughly -79.8523124, 43.2021892.

I hope this helps.

Re: Coordinate System and converion

rajujee — Thu, 30 Apr 2020 18:19:12 GMT

Thanks Bojan for helpful information. I have related question. I am using esri map service to project these values into WGS84(WKID 3857). Can I publish in meter as 'display unit' . Is it possible?

Re: Coordinate System and converion

BojanŠavrič — Thu, 30 Apr 2020 21:04:34 GMT

I am not familiar how exactly map service works or if you can use linear units on WGS84, but those values should always be in angular units. Meters do not make any sense when data is in geographic coordinates: a degree span at the equator is different then 1 degree near a pole.