The Benefits of an Accurate Survey Data Model
By Ian Harper and Craig Sandy
Surveyors are renowned for not throwing away anything. Every job they have worked on contains some elements of survey information in their records that may be of benefit to them in the future. Thus for years, their file records on paper have been retained as their personal database. The survey plans of subdivisions done by other surveyors and stored on paper in county or state offices are their public database.
The advent of computers and coordinate geometry software then allowed them to store their own measurements locally to create and manage a personal electronic survey database.
We see a future with an electronic geodetic survey database that is accessible to surveyors to use to commence a job; then upon completion of that job, they can add data to it and, most importantly, contribute to improving the spatial quality of that database for the benefit of all.
Surveyors need the ability to electronically access survey data, upload it to their field equipment, record new data, and then manage it. Most electronic field equipment offers this capability as does most survey coordinate geometry software, but they lack the ability to properly manage the data when the surveyor completes the fieldwork and computations. ArcGIS Survey Analyst does all this but, most importantly, enables that data to be entered and stored in a survey database and exported as needed.
Surveyors are creating a survey data model in the office prior to commencing fieldwork to find problems between plans or errors in plans. Time savings may be realized by planning fieldwork with the knowledge of where problems exist.
Surveyors are also taking the survey data model into the field to locate remote or buried survey marks with handheld GPS or real-time kinematic (RTK) GPS with submeter accuracy. Once a survey mark is found, new coordinates can be attributed to that point in the model; the adjustment can be run; and within 15 minutes, the surveyor is then searching for the next mark with much higher precision. This has been a great benefit in rural areas or rugged terrain.
As new surveys are completed, a surveyor builds up a survey database. This information is suitable for recycling for future surveys in the same area. This saves on searching and data entry time and cost on new surveys.
In local government and utilities, surveyors have the ability to work closely with the GIS staff in a mutually beneficial environment. The surveyor is able to collect accurate information on quality and condition of assets for the GIS and provide updates where survey measurements change. The GIS can assist the surveyor with additional information that may assist in locating survey marks, for example, offsets to marks from curbs or power lines, and can utilize information within the GIS for fieldwork. Working as a team, the surveyors meet the requirements of the organization by maintaining a survey-accurate asset management system.
The role of the surveyor is not being replaced, as the survey data model is created from the measurements of surveyors who have defined titles by deed dimensions. This database will only retain this quality if it is maintained by surveyors who understand boundary definition.
With the future advent of coordinated cadastres and proclaimed survey areas, Esri Cadastral Editor provides a system for the management of the boundaries in these areas. Cadastral Editor has the ability to import the existing measurements, adjust boundaries to the control, and maintain cadastral fabric. In addition, the other information within the GIS can be linked to the real representations of the boundaries.
About the Authors
Ian Harper is a principal of Geodata Information Systems in Australia and a registered surveyor, and Craig Sandy is business manager at Esri Australia Pty. Ltd., Esri's distributor in Australia.
For more information, contact Ian Harper, Geodata Information Systems (e-mail: firstname.lastname@example.org); Craig Sandy, Esri Australia (e-mail: email@example.com); or Brent Jones, Esri (e-mail: firstname.lastname@example.org).