Date:         Fri, 7 Jul 2006 13:20:44 -0400
Reply-To:     Subject Coordinates Discussion List <[log in to unmask]>
Sender:       Subject Coordinates Discussion List <[log in to unmask]>
From:         Joe Aufmuth <[log in to unmask]>
Subject:      New thread -- GPS coordinates and place name authorities for new
              coordinate fields
Comments: To: Subject Coordinates Discussion List <[log in to unmask]>
Content-Type: text/plain; charset="iso-8859-1"

I presume they are called authority records for a reason.  So who will be the *authority* for the coordinates collected and the places named?  If selective availability gets turned off for GPS reception a position could vary by at least 200 meters.  There are many other variables effecting GPS accuracy, including signal multipathing.  General GPS users are often unaware of these problems.  Granted accuracy is not the issue as I have previously stated.  The main reason for the fields is to be able to find information about location X,Y.  My question is, who is the appropriate "authority* for naming and collecting coordinates of a location that is used in a catalog record?  In your example, would this be the local historical society?  The researcher who created a particular report or map?  The question of local place name authority records has been the topic of many discussions and I have never heard of any conclusions or recommended procedures concerning how a place name or its coordinates are chosen.  I don't care who does it or how, so long as the metadata is complete enough to allow me, or any other user, to determine if the accuracy is sufficient for a particular purpose.

One thing we all agree on is your statement "[in a separate subfield
from the coordinates, please, which will make machine processing and
indexing easier]"  -- this really is the whole point of the discussion.

Joe

-----Original Message-----
From: Subject Coordinates Discussion List [mailto:[log in to unmask]]On
Behalf Of Houghton,Andrew
Sent: Thursday, July 06, 2006 9:38 AM
To: [log in to unmask]
Subject: Re: [SUBCOOR] The proposal passed MARBI!


> -----Original Message-----
> From: Subject Coordinates Discussion List 
> [mailto:[log in to unmask]] On Behalf Of Joe Aufmuth
> Sent: 03 July, 2006 09:43
> To: [log in to unmask]
> Subject: Re: [SUBCOOR] The proposal passed MARBI!
> 
> If we're going to use GPS for authority records, what level 
> of accuracy will be acceptable?  Will there be a standardized 
> method of collection?  Typical handheld "walmart" receivers 
> greatly vary in their measurements.  Elevations in particular 
> can be quite poor.  So, who will be generating the authority 
> records and the subsequent coordinates and elevations?  
> Surveyors?  GNIS?  NGA? Catalogers?  Who will be testing the 
> accuracy of the coordinates used?

The question is how important *is* accuracy?  That handheld
Wal-Mart receiver might be +/- 30 meters and a surveyor's unit
in the centimeters range.  Does that really make a difference
when a patron wants to know the general vicinity someplace is?

Now, these coordinates could be used for other purposes, where
accuracy might be an issue.  However, lets say there is a local
place of historical significance to your community.  It doesn't
appear in any GNIS database.  So are you going to pay a surveyor
several hundred dollars to give you the coordinates or are you
just going to send someone to the place with a handheld unit to
take measurements?

Certainly the answer to that question depends on a number of 
factors.  The format should provide information on the collection 
method.  When a more accurate method is available, then certainly 
it would be best to record that information or update the originally 
collected information.

The point being, the format shouldn't dictate one collection method 
over another, but provide a place to record the type of collection 
method in addition to the actual coordinates. [in a separate subfield
from the coordinates, please, which will make machine processing and
indexing easier]


Andy.