GIS questions

[Anonymous]

does anyone know the specific difference between AZ83-CIF and AZHP-CIF coordinate system?  Is it an elevation difference?

thanks

Brenda

[parkr4st]

Brenda

AZ83-CIF is NAD83 international feet

AZHP-CIF is HARN(HPGN) based

http://www.ngs.noaa.gov/faq.shtml  site offers an explanation  (click on what is HARN or HPGN)

Dave

[harold.jones]

Following this conversation, as I have the same question.  A consultant provided a base map that purports to be in AZHP-CIF, but we normally use AZ83-CIF.  When I "query" their drawing from within Civil3D, this consultant's base map is about 62.5-ft north of where I think it should be based on our own internal base maps.  So far no one from my agency nor this consultant, have been able to give me a satisfactory explanation.  All of this is sort of confusing, but thank goodness there are folks who specialize in geodetic survey.  I am not too, too concerned because the project will get built with respect to at least two "known" survey benchmarks and an assumed basis of bearing, but I am just trying to get smarter about this stuff and always worried about surprises.  Ha Ha

[ChicagoLooper]

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@harold.jones wrote:

<<.......A consultant provided a base map that purports to be in AZHP-CIF.....>>

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Does this consultants drawing have an assigned coordinate system? If it doesn't, then the drawing may not be AZHP-CIF at all but something else or not have an assigned coordinate system at all.  

What happens when you turn on Bing Hybrid Map in the consultant's drawing? Does the Bing basemap look correct? If it does, then fine, but if it does NOT then there are two possibilities:

1. AZHP-CIF is not an appropriate coordinate system for the site, OR
2. The consultant's method used to assign AZHP-CIF to modelspace is incorrect which has resulted in a northing error of +/-62 feet.