topic Re: ARCMAP - READING TRANSFORATION / PROJECTION TABLES in Data Management Questions

ARCMAP - READING TRANSFORATION / PROJECTION TABLES

ChuckTurlington — Mon, 29 May 2017 21:31:02 GMT

Hello,

I am using ArcMap 10.4.1 to performing Transformation/Projection using Project under Arc Tool Box Projections and Transformations. If I wanted to check the Transformation / Projection table applied to my point, is it possible to review this information ?

Re: ARCMAP - READING TRANSFORATION / PROJECTION TABLES

DanPatterson_Retired — Mon, 29 May 2017 23:57:57 GMT

from here do you mean grid based?

Re: ARCMAP - READING TRANSFORATION / PROJECTION TABLES

ChuckTurlington — Tue, 30 May 2017 01:49:07 GMT

Are the Grid Based Methods what ESRI uses in the background calculations ?

Re: ARCMAP - READING TRANSFORATION / PROJECTION TABLES

DanPatterson_Retired — Tue, 30 May 2017 01:58:27 GMT

Chuck in the main section on transformation, equation-based and grid-based... the grid-based ones you will notice are documented for the US and Canada since they are using reference points. Australia and New Zealand have adopted the NTv2 method as well. If you are talking about a specific projection or coordinate system, then you have to specify which one you are talking about. There are links for specific ones like NAD83 to WGS84 etc.

Re: ARCMAP - READING TRANSFORATION / PROJECTION TABLES

ChuckTurlington — Tue, 30 May 2017 12:15:47 GMT

Thanks Dan,

I am referring to moving between WGS84 (geographical, meters), and NAD83 Int'l feet or NAD83 US feet mostly.

Re: ARCMAP - READING TRANSFORATION / PROJECTION TABLES

VinceAngelo — Tue, 30 May 2017 14:01:21 GMT

It's not possible to have WGS84 GCS with units of meters (geographic coordinate systems always have angular units). Only a projected coordinate system (PCS) could have units of meters. If you don't know where you are, it will be difficult to get where you want to go.

- V