Metzger + Willard, Inc. (MWI) survey personnel have a wide range of experience in delivering land surveying products including route surveys, boundary surveys, topographic surveys, legal descriptions and sketches, right-of-way maps, construction staking, as-built surveys, and wetland delineation surveys. Past projects include the real-time kinematic (RTK) Global Positioning System (GPS) location of approximately 30,000 utility components with centimeter accuracy and various route surveys totaling more than 50 miles. Our Chief Surveyor, Dr. Tom Davis, holds dual registration as a professional engineer and land surveyor with more than 25 years of experience in industry and education.
Equipment and Computer Software
Survey equipment used by MWI field personnel includes Sokkia and Topcon electronic total stations, Leica robotic total stations, Leica and Topcon differential levels, Leica RTK GPS receivers, Ashtech static GPS receivers, Carlson Explorer survey data collectors, Motorola radios, and fully equipped, late model survey trucks.
MWI uses Carlson Survey with Carlson X-Port to collect, process, and adjust total station survey data. Differential level runs are processed and adjusted using Microsoft Excel; GPS data are processed and adjusted using Ashtech Solutions and Leica Geo Office. Carlson Survey provides extensive coordinate geometry capabilities that are used to produce land surveys and base maps with final editing and layout accomplished in AutoCAD or Civil 3D, depending on client requirements and preferences.
United States Geological Survey (USGS) and Environmental Systems Research Institute (ESRI) data file formats are accommodated by Global Mapper and ArcGIS for survey planning and preliminary mapping functions. Additionally, MWI’s Survey Department has the ability to write in-house computer software to process survey data and provide extended functionality in AutoCAD and other applications. Innovative technologies to visualize National Geodetic Survey Control Stations (NGSCS) (Fig. 1) and other geodetic tools for Google Earth are currently under development.
Figure 1. NGS Reference Marks
Quality Assurance/Quality Control Plan
Surveying jobs begin with static or RTK GPS sessions to establish two or more on-site control points. Static GPS sessions involve NGS horizontal control monuments of first or higher order, while RTK GPS sessions rely on the Florida Permanent Reference Network (FPRN) (Fig. 2) to provide access to continuously operating reference stations (CORS) with real-time differential network corrections. All static GPS sessions are adjusted in a single network and subjected to rigorous quality tests before acceptance.
Additional control points are located as vertices in one or more closed traverses with established horizontal control as initial and terminal points. All traverses are checked for acceptable angular and linear closure before adjustment.
Figure 2. FPRN CORS
All control points are included in one or more closed differential level runs with benchmarks of third or higher order. All level runs are checked for acceptable closure and adjusted. All secondary survey points are located from adjusted and leveled control with foresight limits that yield trigonometrically leveled elevations of acceptable accuracy.
The survey is mapped on a high resolution, color orthophoto (Fig. 3) before drafting. Knowledgeable technicians, typically with field experience, complete the map from field notes with reference to the orthophoto. Any discrepancies are resolved in either the office or field, and finally, a project walkthrough is performed by a crew chief, comparing the map to features on the ground. The MWI survey map is a superior product with mnemonically named layers for each attribute of every point code and adheres to high standards established by our CADD Manager and Autodesk Certified Professional, Jason Stilp, in compliance with client requirements.
Figure 3. Color Orthophoto
MWI makes every effort to provide survey staff members with a safe and healthful work environment. MWI’s Safety Program incorporates by reference the Florida Department of Transportation (FDOT) Survey Safety Handbook (SSH). All survey employees actively participate in the Program by completing and signing the Safety Indoctrination form (SSH, Exhibit “A”). Many survey employees hold current first aid, cardiopulmonary resuscitation, or automated external defibrillator (FA/CPR/AED) certification. Our Subsurface Utility Engineering (SUE) Manager and Safety Officer, Larry Murray, has more than 25 years of experience in the land surveying industry and supervises all work in rights-of-way and other hazardous areas. Mr. Murray has current certification in FDOT Maintenance of Traffic (MOT) from the Tampa Area Safety Council (TASC).