topic Re: ArcGIS Pro 2.5: What does the “angular unit” represent in the geographic coordinate system? in ArcGIS Pro Questions

ArcGIS Pro 2.5: What does the “angular unit” represent in the geographic coordinate system?

JamalNUMAN — Fri, 12 Jun 2020 18:37:41 GMT

ArcGIS Pro 2.5: What does the “angular unit” represent in the geographic coordinate system?

I couldn’t figure out what does the “angular unit” represent in the Geographic coordinate system

Re: ArcGIS Pro 2.5: What does the “angular unit” represent in the geographic coordinate system?

DanPatterson — Fri, 12 Jun 2020 20:08:59 GMT

in general, angular units can be in degrees (or its variants like DMS), radians, grads or gons .

It is a property of a GCS and important in raster projection amongst other things.

Unit options—ArcGIS Pro | Documentation

Direction units for editing—ArcGIS Pro | Documentation

How the Cell Size Projection Method environment setting works—Geoprocessing | Documentation

Re: ArcGIS Pro 2.5: What does the “angular unit” represent in the geographic coordinate system?

JamalNUMAN — Fri, 12 Jun 2020 20:23:24 GMT

Right, but it’s not clear what does it represent.

For example, for the “Clarke 1880 Benoit” spheroid and “D Palestine 1923” Datum, the angular unit is 0.0174532925199433.

What does this value represent? What does it indicate for in terms of geometry?

Re: ArcGIS Pro 2.5: What does the “angular unit” represent in the geographic coordinate system?

JoshuaBixby — Fri, 12 Jun 2020 20:34:07 GMT

Geographic coordinate systems require an angular unit, but the value of the angular unit is really about geometry and not geography. Since radians are the international unit for measuring angles, a geographic coordinate system that wants to use degrees or some other angular unit of measure must provide a conversion factor. Since there are 2*pi radians in 360 degrees, 1 degree equals 0.0174532925199432.... radians.

Re: ArcGIS Pro 2.5: What does the “angular unit” represent in the geographic coordinate system?

JamalNUMAN — Fri, 12 Jun 2020 21:00:30 GMT

Many thanks guys for the help.

It could be less confusing if the word radian follows the number

Angular Unit = Degree (0.0174532925199433 Radians)

I could see that the linear unit conforms with same logic

Linear unit: meter (1.0)

Re: ArcGIS Pro 2.5: What does the “angular unit” represent in the geographic coordinate system?

DamilolaOlufemi — Thu, 18 Jun 2020 01:59:11 GMT

I think it also shows the ground/real measurement of the location. Hence the angular unit indicates the geometry of the area