California Surveyors Forums

Hello,

Any of you experienced in writing airport parcel descriptions using geodetic coordinates?

I am creating a parcel description which relies on an airport runway that is located by geodetic coordinates (Lat & Long). The parcel being described is a portion of a parcel of a parcel map lying westerly of a runway protection zone parcel. I must describe the runway protection zone parcel which is a strip of land at the end of the runway.

This is a first for me in mixing geodetic positions with parcels that have been created by subdivision so I would invite any advice or cautions when writing the description.

David

Please consider reviewing "Advanced Land Descriptions."

http://www.pallamaryandassociates.com/b ... vLand.html

http://www.amazon.com/Advanced-Land-Des ... 0910845530

Awesome!! Thank you Mr. Pallamary

The survey should be tied to the two primary airport control points published by NGS

My caution is to make sure your work is based on the same epoch (and datum for that matter) that was used for the geodetic coordinate listing of the protection zone. The same position will have shifts in the NAD 83 lat/ long for different epochs. Sometimes quite significantly.

make multiple ties within the description to ensure the Intent is clear.

Here is a good example of what not to do.

BTW, the federal government just issued a letter addressing the issues I raised and based upon these problems, they are revising the development of data like this.

Here is the letter the feds just issued.

Michael,

Thanks for posting that! I followed the link and read the white paper on how the SLA boundary was established. Good stuff!

Yes, what pleases me the most is the feds recognized there was a problem and they are fixing it. I am a huge fan of public/private collaborations. They always seem the best route. You are a prime example if that approach. We need a thousand more guys and gals out there like you!

mpallamary wrote:Here is a good example of what not to do.

BTW, the federal government just issued a letter addressing the issues I raised and based upon these problems, they are revising the development of data like this.

I suggest you re-read the reference document the BOEM refers to in their letter. Note its title includes the statement "A Federal-State Success Story".

In reading the letter and the linked reference document, it is clear that their effort is purely to counter your article, much as Chuck and Evan have done themselves.

They are not "fixing" or changing anything in their process. Instead their efforts with this latest letter and white paper are intended to better educate the survey community on their successful efforts that culminated in the U.S. Supreme Court ruling. In their (and mine and many others) eyes, a successful ruling they had sought.

Suler, John. "The online disinhibition effect." Cyberpsychology & behavior 7.3 (2004): 321-326.

Michael,

That is a fascinating read. I especially relate to the Minimization of Status and Authority. I am intrigued with the interaction of LSITs and students with elder statesmen and those of us a little long in the tooth.

To your point - what I call the Stan Myron effect - anonymous posters; if only I could bring myself to adopt an alter ego. Hmmm ...

Some of us longer than others.......

BTW, I just received a wonderful email from the staff at BOEM. They are going to let me know the next time they work on a state/federal boundary line. We may collaborate on covering the process.

Warren, I have been and am involved in several cases involving boundary disputes along the shoreline and state lands. When we were in the middle of one of these, I received the attached in an unmarked, brown envelope postmarked from Sacramento.

Sophomoric indeed.

Wow, well you must have touched a nerve somewhere ...

Steve Martin wrote:The survey should be tied to the two primary airport control points published by NGS

Steve,

When you say "control points" are you referring to physical monuments (control points), or locations (may not be monumented), that are published by NGS. The NGS has geodetic coordinate values at the two ends of the runway however monuments found in the field are not found listed in the NGS data sheets.

Check out the photo of a monument found that appears to be a tie to the runway end. I wish it the stamping identified who set it.

David

David,

There is a lot of information on Aeronatical surveys on the NGS web page:

http://www.ngs.noaa.gov/AERO/aero.html

There is a link to the Primary airport control Station (PACS) and Secondary Airport Control Station (SACS) in the NGS database:

http://www.ngs.noaa.gov/cgi-bin/airport ... YPE=PACSAC

For the monument in your photo, have you checked with the Surveyors at the agency that owns the airport? i.e. County airport, City airport or Port District? Often times they will have reams of records for historical surveys.

When I worked for the County, we already had a 1st order control survey at McClellan/ Palomar Airport (CRQ) before NGS came thru with their airport control surveys and set new points.

It should be worth noting that not all Airports have PACS/SACS. Secondly, nails set at the ends of the runways may not be at the published coordinates provided by the NGS for the FAA, which are runway ends for the declared distances. I would suggest re-observing the nails and then inversing the distance to compare with the published distance (if available) of the runway. I would assume you would be writing the description for the Approach RPZ, which starts 200' from the threshold, which may not be the runway end if there is a displaced threshold.

Steve is correct on getting as much information from the Airport Manager/engineer. Sometimes Airport Layout Plans will not be the most accurate in their information, as they are a planning tool for future engineering projects. Try to find previous design plans for the runway, most runway pavements have a life of around 20 years, so you should be able to at least find a resurfacing plan set that is relatively recent.

Brad Luken

Thank you all.

Unfortunately our little airport is not listed by the NGS for PAC and SAC marks. The RPZ does start at 200-feet. True that the airport layout is not that accurate. I noticed that the lat and long listed for the new runway ends did not round the fraction of seconds correctly (simply dropped the trailing digit).

If anyone would like to critique the description I wrote I would welcome the scathing.

David

If you would like, I can take a look at it. Will this be used for an avigation easement? Send it to: brad.luken@flysfo.com