Surveying, Surveyors and Geographic Information Systems Curt Crow NOAA s National Geodetic Survey September 22, 2009 URISA New England, Bedford, NH
Surveying The technique and science of accurately determining the location of points on or near the surface of the earth and the distances and angles between them. Surveying by Francis H. Moffitt
Surveying To accomplish their objective, surveyors use elements of: geometry, engineering, trigonometry, mathematics, physics, and law geometry: from Greek geōmetriā, to measure land : geō-, geo- + metron, measure
Land Surveying The detailed study or inspection, as by gathering information through observations, measurements in the field, research of legal instruments, and data analysis in the support of planning, designing, and establishing of property boundaries. It often involves the re-establishment of cadastral surveys and land boundaries based on documents of record and historical evidence, as well as certifying surveys of subdivision plats/maps, registered land surveys, judicial surveys, and space delineation. from the American Congress of Surveying and Mapping
Land surveying includes associated services such as: mapping and related data accumulation construction layout surveys precision measurements of length, angle, elevation, area, and volume horizontal and vertical control surveys the analysis and utilization of land data
Surveying through History Surveying has been an essential element in the development of the human environment since the beginning of recorded history (ca. 5000 years ago) and it is a requirement in the planning and execution of nearly every form of construction. Its most familiar modern uses are in the fields of transport, building and construction, communications, mapping, and the definition of legal boundaries for land ownership.
Egyptian Surveys the Rope Stretchers In ancient Egypt, when the Nile River overflowed its banks and washed out farm boundaries, boundaries were re-established by a rope stretcher, or surveyor, through the application of simple geometry.
Egyptian Surveys the Pyramids The nearly perfect squareness and north-south orientation of the Great Pyramid of Giza, built c. 2700 BC, affirm the Egyptians' command of surveying.
Stonehenge 2500 BC Recent discoveries indicate that the monument was set out by prehistoric surveyors using peg and rope geometry
Roman and Arab Empires The Romans, established land surveying as a profession and they established the basic measurements under which the Roman Empire was divided including a tax register of conquered lands (300 AD). The rise of the Caliphate led to extensive surveying throughout the Arab Empire. Arabic surveyors invented a variety of specialized instruments for surveying, including: Instruments for accurate leveling: A wooden board with a plumb line and two hooks, an equilateral triangle with a plumb line and two hooks, and a reed level. A rotating alhidade, used for accurate alignment A surveying astrolabe, used for alignment and measuring angles
England and Europe In England, The Domesday Book by William the Conqueror (1086) contained names of the land owners, area, land quality, and specific information of the area's content and habitants. But, it did not include maps showing exact locations Continental Europe's Cadastre, created by Napoleon Bonaparte (1808) contained numbers of the parcels of land (or just land), land usage, names and value of the land 100 million parcels of land surveyed and mapped at scales of: 1:2500 and 1:1250 The Cadastre spread quickly around Europe but faced problems in Mediterranean countries, Balkan, and Eastern Europe due to cadastre upkeep costs and troubles "A good cadastre will be my greatest achievement in my civil law NB
The Survey of the Coast On February 10, 1807, President Thomas Jefferson founded the Survey of the Coast to provide nautical charts to the maritime community for safe passage into American ports and along our extensive coastline. Later known as the Coast and Geodetic Survey and now known as NOAA s National Geodetic Survey
Three Surveyors and some other guy
The Last Spike (1881) by Thomas Hill
Jupiter & #119 May 10, 1869 at Promontory Summit, Utah
A Surveyor's Five Main Areas of Work Research, analysis, and decision making Field work - Data acquisition Computing - Data processing Mapping - Data representation Stake-out - Positioning points on the ground
The Two Major Methods of Surveying Geodetic Surveying Takes into account the shape of the earth. Generally high in accuracy and covers large areas Plane Surveying Assumes that the measurements are made on a flat plane. Generally covers smaller areas
Types Of Surveys Control establishes the position of arbitrary horizontal and vertical points for the support of subsequent surveys and precise mapping. Topographic determines the configuration of the surface of the earth and objects on that surface. Cadastral establishes the positions of boundary or property lines. (aka Property or Boundary Survey) Construction lays out the horizontal and vertical positions of objects of a designed project. Hydrographic determines the depth of water, configuration of the bottom and heights and times of tides in a body of water. Many more types including Route Surveys, Forensic Surveys
What do a GIS and a Survey have in Common? Both are information management systems which can: Collect, store, and retrieve information based on it s spatial location Identify locations which meet specific criteria within a targeted area Explore relationships among data sets Spatially analyze the data within each area Display and analysis of the selected area numerically and graphically
Building the Foundation All of this data is georeferenced: linked to a specific location on the surface of the Earth through a system of coordinates A GIS or a survey are not limited to objects and their position, both can incorporate properties of these objects as additional data within the project Understanding the framework is critical, ie. datums and coordinate systems
Coordinate Systems Surveyors are knowledgeable about Mapping Datums. They routinely deal with: Current and historic datums Geodetic and tidal datums Maps and charts with No Datums Surveyors have experience finding solutions to spatial problems in the field
Accuracy The surveyor and the GIS specialist have approached accuracy from opposite directions Surveyors are skilled in measurement techniques GIS specialists manage, analyze and display large amounts of critical data from a wide variety of sources High speed computers, sophisticated mapping software and GPS have brought them together The massive amount of data collected with mapping grade and sub-meter GPS brought GIS from digital renderings to spatially correct drawings
Surveyors and GIS Specialists have a Problem Surveyors are driven by the details GIS Specialists see the big picture For the most part, each understands the limitations of their data Problems arise when the Surveyor or the GIS Specialist or, more commonly, a third party misunderstands that data, or the map or the coordinate values derived from a digital model
Technology Stops for No One mapping grade and sub-meter GPS made GIS accurate to a point, but technology rolled on like that train in Utah New high-resolution, stable platform, precisely controlled digital imagery has made 1-meter photos look like cave drawings. In less than ten years we have gone from 1-meter imagery to 3- inch imagery We ve rubber-sheeted very old data to match the new maps. Now we have to rubber-sheet the good data to match the really good imagery
New Relationships The GIS and Survey communities need to work together to utilize each others skills. Surveyors can help keep the data in sync For example: a community obtains new orthophotography that is more accurate than the existing base data in their GIS. Surveyors have the equipment, technology and expertise to perform these spatial updates From an online interview with Brent Jones, Survey Manager, ESRI
Where does Survey fit in the GIS World? Surveyors can: Assist in the establishment of the control and parcel base Collect data of geographic features to improve the accuracy of remotely sensed imagery like orthophotos Develop the points, lines, and areas for import into the GIS Use their measurement knowledge to write the Metadata Assist in the planning, development, and maintenance of the GIS