Hi All

I hope this post find everyone well and in good health

  1. Explain how differences in heights are reduced by adapting the raw   

              measurements to refined data. Explain reductions relating to sea level, close,

              and mean. 

Any help would be appreciated

Regards

MAt

This Content Originally Published by a land surveyor to Land Surveyors United Network

Views: 361

See Your Saved Posts Timeline

☇ Reply to this

Replies to This Discussion

I need a more clear question. What's your survey project and are you dealing with littoral data???

Dear Mr. Win,

I will try to give an explanation, but first, here are a few links to previous comments.

Link 1
Link 2
Link 3

Link 4
Link 5

  • Explain how differences in heights are reduced by adapting the raw measurements to refined data.

Perhaps the best short explanation I have is to consider people who speak different languages but who think it is the same one, e.g., Britain and U.S. natives. Some of the sentences almost make sense but some of the words used need to be correlated.

Let's take a simple example of elevations in which the measured elevations seem slanted. They are higher on the east  relative to the ones on the west. If our project controls are supposed to rule the project and adjustment of our observations by tilting your observations until they agree with the control. that was an oversimplification, of course, but not too far off.

An adjustment (or localization/calibration) develops the necessary functions to bring your observations into conformity with the control. Adjustment can be quite simple or ridiculeslycomplex, but their purposes are to do what I described.

Often one or more observations or control points will prove to be outliers and removed from the process.

  • Explain reductions relating to sea level, close, and mean.

MSL:  Sea Level is an average value of the level of the sea at a tide guage over an 18.6 year period, the time it takes for all the influences on the tides to cycle through.

At one time, (in large part because running levels for any great distance was a daunting task) the CSG&GS took the MSL at several guages around North America averaged their MSLs and developed the MSL29 vertical datum. It bacame obvious that these were not actually MSL, so the datum was renamed NAVD29. Since leveling was a local affair it served until the 1980s.

We now have a better datum, a hybrid datum called NGVD88. Its zero is far more consistent but NOT MSL because MSL only exists at a tide guage. So much for MSL. Except at tite guages, we don't know where MSL is.

Close:  I presume you mean the verb close = to shut. In surveying parlence, to close means for an observation to agree with a previous one. A level loop closes if the ending value is the same or very nearly the same as the original value.

Mean:  Again, I'm not sure of your request. Mean = simple average of some numbers.

I hope you find this helpful.

JAC

http://opencommons.uconn.edu/thmeyer_articles/2

What Does Height Really Mean

Meyer, Roman, Zilowski     2006

Yes! Tom's, Dan's and Dave's essay is a great source.

Thanks, Mr. Noblitt.

JAC

im guessing the question is written way that everyone interrupts it differently.

The explanantion is meant to include or show how differences in heights are reduced by adapting the raw measurements to refined data. Their explanation must cover reductions relating to sea level, close and mean. Explanations may include these points:

Curvature and vertical refraction zenith angles measured for horizontal and vertical reduction of long lines require curvature and refraction corrections.

The manufacturer’s specifications for most total stations indicate that the earth's curvature and atmospheric refraction are internally computed and the corrected horizontal and vertical distances displayed. This correction can be eliminated (or balanced) by taking the mean of two reciprocal measurements.

The reciprocal procedure means that a distance and a zenith angle are measured at point A to point B and then from point B back to point A.

At longer distances -- over 1000 meters (3280.8 feet) -- it is better to use this averaging solution than the on board correction factors provided within these total stations, even when they are in perfect adjustment.

i maybe readying into the question way too much who knows

thanks for your help tho

Cheers

Mat

RSS

Where Thousands of Professional Land Surveyors, Students of Surveying and Educators are United through Collaborative Knowledge and Purpose.

Dedicated to the Memory of Skip Farrow (1953-2015)

+ Surveyor Sharer

Drag Button to bookmark bar and view submitted links here.Will soon be moved to a directory

AFGHANISTAN SURVEYORS ALBANIA SURVEYORS ALGERIA SURVEYORS AMERICAN SAMOA SURVEYORS ANDORRA SURVEYORS
ANGOLA SURVEYORS ANGUILLA SURVEYORS ANTIGUA & BARBUDA SURVEYORS ARGENTINA SURVEYORS ARMENIA SURVEYORS
ARUBA SURVEYORS AUSTRALIA SURVEYORS AUSTRIA SURVEYORS AZERBAIJAN SURVEYORS BAHAMAS SURVEYORS
BAHRAIN SURVEYORS BANGLADESH SURVEYORS BARBADOS SURVEYORS BELARUS SURVEYORS BELGIUM SURVEYORS
BELIZE SURVEYORS BENIN SURVEYORS BERMUDA SURVEYORS BHUTAN SURVEYORS BOLIVIA SURVEYORS
BOSNIA & HERZEGOWINA SURVEYORS BOTSWANA SURVEYORS BRAZIL SURVEYORS BRITISH INDIAN OCEAN TERRITORY SURVEYORS
BRUNEI DARUSSALAM SURVEYORS BULGARIA SURVEYORS BURKINA FASO SURVEYORS BURUNDI SURVEYORS CAMBODIA SURVEYORS
CAMEROON SURVEYORS CANADA SURVEYORS CAPE VERDE SURVEYORS CAYMAN ISLANDS SURVEYORS CENTRAL AFRICAN REPUBLIC SURVEYORS
CHAD SURVEYORS CHILE SURVEYORS CHINA SURVEYORS COLOMBIA SURVEYORS COMOROS SURVEYORS
CONGO SURVEYORS DEMOCRATIC REPUBLIC OF THE CONGO SURVEYORS COOK ISLANDS SURVEYORS COSTA RICA SURVEYORS COTE D'IVOIRE SURVEYORS
CROATIA SURVEYORS CUBA SURVEYORS CURACAO SURVEYORS CYPRUS SURVEYORS CZECH REPUBLIC SURVEYORS
DENMARK SURVEYORS DJIBOUTI SURVEYORS DOMINICA SURVEYORS DOMINICAN REPUBLIC SURVEYORS ECUADOR SURVEYORS
EGYPT SURVEYORS EL SALVADOR SURVEYORS EQUATORIAL GUINEA SURVEYORS ERITREA SURVEYORS ESTONIA SURVEYORS
ETHIOPIA SURVEYORS EUROPEAN UNION SURVEYORS FAROE ISLANDS SURVEYORS FIJI SURVEYORS FINLAND SURVEYORS
FRANCE SURVEYORS FRENCH GUIANA SURVEYORS FRENCH POLYNESIA SURVEYORS GABON SURVEYORS GAMBIA SURVEYORS
GEORGIA SURVEYORS GERMANY SURVEYORS GHANA SURVEYORS GIBRALTAR SURVEYORS GREECE SURVEYORS
GREENLAND SURVEYORS GRENADA SURVEYORS GUADELOUPE SURVEYORS GUAM SURVEYORS GUATEMALA SURVEYORS
GUERNSEY SURVEYORS GUINEA SURVEYORS GUINEA-BISSAU SURVEYORS GUYANA SURVEYORS HAITI SURVEYORS
HOLY SEE SURVEYORS HONDURAS SURVEYORS HONG KONG SURVEYORS HUNGARY SURVEYORS ICELAND SURVEYORS
INDIA SURVEYORS INDONESIA SURVEYORS IRAN SURVEYORS IRAQ SURVEYORS IRELAND SURVEYORS
ISLE OF MAN SURVEYORS ISRAEL SURVEYORS ITALY SURVEYORS JAMAICA SURVEYORS JAPAN SURVEYORS
JERSEY SURVEYORS JORDAN SURVEYORS KAZAKHSTAN SURVEYORS KENYA SURVEYORS KIRIBATI SURVEYORS
KOREA SURVEYORS KOREA REPUBLIC OF SURVEYORS KUWAIT SURVEYORS KYRGYZSTAN SURVEYORS LAO PEOPLE'S DEMOCRATIC REPUBLIC SURVEYORS
LATVIA SURVEYORS LEBANON SURVEYORS LESOTHO SURVEYORS LIBERIA SURVEYORS LIBYAN ARAB JAMAHIRIYA SURVEYORS
LIECHTENSTEIN SURVEYORS LITHUANIA SURVEYORS LUXEMBOURG SURVEYORS MACAU SURVEYORS MACEDONIA SURVEYORS
MADAGASCAR SURVEYORS MALAWI SURVEYORS MALAYSIA SURVEYORS MALDIVES SURVEYORS MALI SURVEYORS
MALTA SURVEYORS MARSHALL ISLANDS SURVEYORS MARTINIQUE SURVEYORS MAURITANIA SURVEYORS MAURITIUS SURVEYORS
MAYOTTE SURVEYORS MEXICO SURVEYORS MICRONESIA SURVEYORS MOLDOVA SURVEYORS MONACO SURVEYORS
MONGOLIA SURVEYORS MONTENEGRO SURVEYORS MONTSERRAT SURVEYORS MOROCCO SURVEYORS MOZAMBIQUE SURVEYORS
MYANMAR SURVEYORS NAMIBIA SURVEYORS NAURU SURVEYORS NEPAL SURVEYORS NETHERLANDS SURVEYORS
NEW CALEDONIA SURVEYORS NEW ZEALAND SURVEYORS NICARAGUA SURVEYORS NIGER SURVEYORS NIGERIA SURVEYORS
NIUE SURVEYORS NON-SPEC ASIA PAS LOCATION SURVEYORS NORFOLK ISLAND SURVEYORS NORTHERN MARIANA ISLANDS SURVEYORS NORWAY SURVEYORS
OMAN SURVEYORS PAKISTAN SURVEYORS PALAU SURVEYORS PALESTINIAN TERRITORY OCCUPIED SURVEYORS PANAMA SURVEYORS
PAPUA NEW GUINEA SURVEYORS PARAGUAY SURVEYORS PERU SURVEYORS PHILIPPINES SURVEYORS POLAND SURVEYORS
PORTUGAL SURVEYORS PUERTO RICO SURVEYORS QATAR SURVEYORS RESERVED SURVEYORS REUNION SURVEYORS
ROMANIA SURVEYORS RUSSIAN FEDERATION SURVEYORS RWANDA SURVEYORS SAINT KITTS & NEVIS SURVEYORS SAINT LUCIA SURVEYORS
SAINT MARTIN SURVEYORS SAINT VINCENT & THE GRENADINES SURVEYORS SAMOA SURVEYORS SAN MARINO SURVEYORS SAO TOME & PRINCIPE SURVEYORS
SAUDI ARABIA SURVEYORS SENEGAL SURVEYORS SERBIA SURVEYORS SEYCHELLES SURVEYORS SIERRA LEONE SURVEYORS
SINGAPORE SURVEYORS SINT MAARTEN SURVEYORS SLOVAKIA (SLOVAK REPUBLIC) SURVEYORS SLOVENIA SURVEYORS SOLOMON ISLANDS SURVEYORS
SOMALIA SURVEYORS SOUTH AFRICA SURVEYORS SOUTH SUDAN SURVEYORS SPAIN SURVEYORS SRI LANKA SURVEYORS
ST. PIERRE AND MIQUELON SURVEYORS SUDAN SURVEYORS SURINAME SURVEYORS SWAZILAND SURVEYORS SWEDEN SURVEYORS
SWITZERLAND SURVEYORS SYRIAN ARAB REPUBLIC SURVEYORS TAIWAN; REPUBLIC OF CHINA (ROC) SURVEYORS TAJIKISTAN SURVEYORS TANZANIA UNITED REPUBLIC OF SURVEYORS
THAILAND SURVEYORS TIMOR-LESTE SURVEYORS TOGO SURVEYORS TOKELAU SURVEYORS TONGA SURVEYORS
TRINIDAD AND TOBAGO SURVEYORS TUNISIA SURVEYORS TURKEY SURVEYORS TURKMENISTAN SURVEYORS TURKS AND CAICOS ISLANDS SURVEYORS
TUVALU SURVEYORS UGANDA SURVEYORS UKRAINE SURVEYORS UNITED ARAB EMIRATES SURVEYORS UNITED KINGDOM SURVEYORS
UNITED STATES SURVEYORS URUGUAY SURVEYORS UZBEKISTAN SURVEYORS VANUATU SURVEYORS VENEZUELA SURVEYORS
VIET NAM SURVEYORS VIRGIN ISLANDS (BRITISH) SURVEYORS VIRGIN ISLANDS (U.S.) SURVEYORS WALLIS AND FUTUNA ISLANDS SURVEYORS YEMEN SURVEYORS
ZAMBIA SURVEYORS ZIMBABWE SURVEYORS SURVEYORS

Location Based Surveying Practices

Land Surveyors United is the world's FIRST Global Social Network for geospatial professionals. We have dedicated, geolocated support groups for practically every country, continent and state on earth, for you to utilize for building your personal network. We are all essentially concerned with the same issues, no matter where we are located on earth. However, surveying practices and methods vary depending on the geographic location where we work. If you have noticed similarities and differences between the conditions, laws and practices between two or more areas of the world,discuss it in this forum. Build your reputation online by posting relevant discussions in your local group below.

Join and Introduce Yourself in Your Local Geosocial Forum:

Alabama Alaska Arizona Arkansas California
Colorado Connecticut Delaware Florida Georgia
Hawaii Idaho Illinois Indiana Iowa
Kansas Kentucky Louisiana Maine Maryland
Massachusetts Michigan Minnesota Mississippi Missouri
Montana Nebraska Nevada New Hampshire New Jersey
New Mexico New York North Carolina North Dakota Ohio
Oklahoma Oregon Pennsylvania Rhode Island South Carolina
South Dakota Tennessee Texas Utah Vermont
Virginia Washington West Virginia Wisconsin Wyoming

Not based in the US? Here are other groups for surveyors around the world to join and contribute knowledge and experiences as a land surveyor:

Africa Asia Australia Europe Russia Canada
Antarctica S.America N. America India Malaysia Caribbean

And more... Find your group forum based on location.

Choose Your Equipment Group Here

Handheld US Social Support for Land SurveyorsNIKON Social Support for Land SurveyorsTrimble Social Support for Land SurveyorsTopcon Social Support for Land SurveyorsSokkia Social Support for Land SurveyorsAshtech Social Support for Land SurveyorsNAVCOM Social Support for Land SurveyorsMagellan Social Support for Land SurveyorsLeica Social Support for Land SurveyorsAltus Positioning Social Support for Land SurveyorsMicroSurvey Social Support for Land SurveyorsJuniper Systems Social Support for Land SurveyorsTraverse PC Social Support for Land SurveyorsCarlson Software Social Support for Land Surveyors

what where  
job title, keywords or company
city, state or zip jobs by job search

PLEASE DONATE TODAY. Your generosity preserves surveying and mapping knowledge for future generations. Thank you.

Survey Equipment Troubles?

Geo Visitors Map

Choose Your Group Here

Surveying Equipment Support for Leica, Carlson, Sokkia, Trimble, Topcon, Altus, Nikon equipment


Surveyor Birthdays

Surveyor Birthdays Today

Surveyor Birthdays Tomorrow

© 2017   © Created by Land Surveyors United   Powered by

Badges  |  Contact LSU  |  Privacy Policy  |  Terms of Service

Live Support