topic Re: UTM Map Projections Help and SPCS shapefile in ArcGIS Enterprise Portal Questions

UTM Map Projections Help and SPCS shapefile

timothydeloriea — Wed, 04 Jul 2012 15:24:38 GMT

I am putting together a presentation about map projections and coorinate systems and would greatly appreciate some clarification about UTM Zones and the State Plane Coordinate System (SPCS).

I have a basic understanding of the concepts and usage of these systems, but have come across a usage that is confusing to me. Specifically, my question is:

What is meant by NAD 83 UTM 12 North?

Is it simply the same thing as 12N?

I know (think I know) that in local applications (something that may be plotted on a 1:24,000 map), it is appropriate to use a UTM projection. But for North America, the use of a UTM zone in column N is better suited for regional (multiple states) display; because projections using zone N preserve the general shape and expected apearance, while distance and area are a bit distorted.

For example, when I worked in the desert in southern California we used UTM zone 11S. not 11N

So is UTM 12N sometimes refered to as UTM 12 North because it is often used to display areas of North America? Or am I just mixed up on the matter?

And I also can't find a shapefile displaying the SPCS Zones on a map. Where can I find one of those?

Re: UTM Map Projections Help and SPCS shapefile

HardolphWasteneys — Wed, 04 Jul 2012 19:36:58 GMT

T..,

reasonable question; there is some ambiguity in the nomenclature since the N or S following the UTM ZONE number can refer to either latitude bands, which alpabetically progress from the south to the north, or just Northern hemisphere and Southern hemisphere, thus telling you which way to measure the northing or southing.
Here is a good Wikipedia reference http://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system

Since the origin of all UTM zones is at the central meridian of each zone and on the Equator the latitude band information is redundant once you have a northing or southing for a point. Latitude bands N and S both occur in the northern hemisphere so the S you refer to in California is just that, a latitude band and happens to be north of band N which is just above the equator. Potentially confusing so you should have to state what nomenclature is being used, but in common practice the N and S just refer to North and South.

Hardolph

Re: UTM Map Projections Help and SPCS shapefile

timothydeloriea — Thu, 05 Jul 2012 12:41:27 GMT

Thanks Hardolph! That clears it up for me.

T..,

reasonable question; there is some ambiguity in the nomenclature since the N or S following the UTM ZONE number can refer to either latitude bands, which alpabetically progress from the south to the north, or just Northern hemisphere and Southern hemisphere, thus telling you which way to measure the northing or southing.
Here is a good Wikipedia reference http://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system

Since the origin of all UTM zones is at the central meridian of each zone and on the Equator the latitude band information is redundant once you have a northing or southing for a point. Latitude bands N and S both occur in the northern hemisphere so the S you refer to in California is just that, a latitude band and happens to be north of band N which is just above the equator. Potentially confusing so you should have to state what nomenclature is being used, but in common practice the N and S just refer to North and South.

Hardolph