TAG: Survey Scene

Establishing orthometric heights using GNSS — Part 5

February 3, 2016By
Figure 9. Plot depicting the changes in adjusted heights due to constraining all published NAVD 88 leveling-derived orthometric heights except for station Phaniel (using GEOID12B) .

Basic procedures and tools for ensuring GNNS-derived orthometric heights meet the project’s desired accuracy
In the latest installment of our ongoing series, the focus switches from GNSS-derived ellipsoid heights to procedures and tools for ensuring GNNS-derived orthometric heights meet the project's desired accuracy. read more

Data is the crop: GNSS used by surveyors and farmers

January 6, 2016By
Photo credit: ViaMoi via Foter.com / CC BY-NC-ND

As technology continues to march forward, and storage and data evaluation use grows, the surveyor and the farmer will begin to use each other’s skillsets to increase their own productivity. So how do we get there? First, we must establish how each side uses their prospective GPS tools. read more

Establishing orthometric heights using GNSS — Part 4

December 2, 2015By

Part 1 of this series appeared in the June Survey Scene newsletter, Part 2 appeared in the August newsletter, and Part 3 appeared in the October newsletter. Upcoming Survey Scene newsletters will carry additional columns in this series. Basic Procedures and Tools for Ensuring GNNS-Derived Ellipsoid Heights Meet the Project’s Desired Accuracy In Part 1 of this series, I discussed the basic concepts of GNSS-derived... read more

Technology Adoption Slow in Small Towns

November 4, 2015By

I was born in a small town and I live in a small town. I’ll probably die in a small town, but only if you want to call a blue-collar city of 75,000 people small. My friends are small town and my parents still live here in this same small town. It was here in this small town that I... read more

This article is tagged with , and posted in Opinions, Survey

Establishing Orthometric Heights Using GNSS — Part 3

October 7, 2015By
A depiction of the United States geoid. Areas in yellow and orange have a slightly stronger gravity field as a result of the Rocky Mountains.

Part 3 describes the differences between a scientific gravimetric geoid model and a hybrid geoid model, and why it is important to use both geoid models in your analysis. read more

More, More, More. Accuracy, Accuracy, Accuracy.

September 2, 2015By
How accurate is good enough for the majority of this sector?

Reliable, consistent positioning accuracy has always driven new product development in the survey and mapping sector of the GPS/GNSS market. It’s remarkable how quickly the provided accuracy in successive new survey products over the years has increased the required accuracy from users and customers in the field, and consequently the desired accuracy in a feedback loop to the product developers.... read more

Establishing Orthometric Heights Using GNSS — Part 2

August 5, 2015By
Figure 2. NAD 83 (2011) Network Design for Stations EA0873 and EA0875. [Note: GNSS Vectors for GNSS projects GPS 1588 and GPS 2057 were provided by NGS].

GNSS-derived ellipsoid heights are the basis for GNSS-derived orthometric heights, so it makes sense to make these ellipsoid heights as close to error free as possible. This article will discuss guidelines for detecting, reducing andr eliminating error sources in ellipsoid heights. It will focus on guidelines for establishing accurate ellipsoid heights in a local geodetic network. (Part 2 of a series) read more

Establishing Orthometric Heights Using GNSS — Part 1

June 3, 2015By and
David B. Zilkoski

Editor’s Note: This month, we introduce a column by David B. Zilkoski, one of our two new Survey Scene editors. Zilkoski has worked in the fields of geodesy and surveying for more than 40 years, including serving as director of the National Geodetic Survey. See his full bio at the end of this article. He is joined by coeditor David Doyle, who contributed the May column. The Three Types of... read more