[PPT1] Introduction to Surveying and Mapping Flashcards
Geomatics
- the science concerned with the measurement, representation, analysis, management, retrieval and display of spatial information describing both the Earth’s physical features and the built environment.
- includes disciplines such as: Surveying, Geodesy, Remote Sensing & Photogrammetry, Cartography, Geographic Information Systems, Global Positioning Systems
Surveying
- The art of making measurements of the relative positions of natural and man-made features on the earth’s surface, and the presentation of this information either graphically or
numerically. (NJDOT Survey Manual, p.3) - The art and science of determining angular and linear
measurements to establish the form, extent, and relative position of points, lines, and areas on or near the surface of the earth or on other extraterrestrial bodies through applied mathematics and the use of specialized equipment and techniques. (J.P. La Putt, 1987)
Professional Surveying
The application of knowledge of the:
– science of surveying measurement;
– legal principles of boundary location;
– laws related to boundaries & land use;
– applicable mathematical & computational theories and
principles;
– natural & other forces which affect positional accuracy;
– land planning & development concepts pertinent to
subdivision of land & property surveys;
– land record & land tenure concepts;
– geodetic & other earth-related sciences to the analysis, design, & execution of surveying & mapping projects & the design of land mapping
The Surveyor
A surveyor is a professional person with the academic qualifications and technical expertise to:
– practice the science of measurement;
– assemble and assess geographic related information;
– use that information for the purpose of planning and
implementing the efficient administration of the land, the sea and structures thereon; and
– instigate the advancement and development of such
practices.
Eratosthenes (276 BC-194 BC)
- Some claimed that his measurements are with an error
of less than 2% and that was 2200 years ago! - However, most literatures cited his measurement as
16% too big compared to the accepted modern circumference of the earth around the poles.
School of Surveying (150 BC)
School of surveying was established by Romans to teach:
* town planning
* map making and
* building of roads and aqueducts
Ptolemy produced maps (120 BC)
“If the earth was spherical then a proper representation could be obtained by a geometrical projection of that surface”
“What can be mapped could be ruled.”
An old belief that was the main reason for people to study Surveying.
Ancient Surveying Instruments
- Astrolabe
- Dioptra
- Roman Groma
- Libella
- Merchet
1. Astrolabe
- Developed sometime in 140 B.C.
- Credited to Hipparchus
- Further improved by Ptolemy
- Metal circle, pointer hinged at the center, held by a ring at the top
- Originally designed for determining the altitude of stars
- Ptolemy’s version is an astronomical instrument
on which the celestial sphere is projected stereographically
2. Dioptra
- Perfected by Heron of Alexandria
- Used in leveling and measuring horizontal and vertical angles
- Mounted on a tripod (50 cm tall)
- Apparatus pivoted on a circular plate, moved around by a worm screw, driven by a small handle
- The top plate was mounted on a toothed semicircular plate and was adjusted in the vertical plane by another worm drive.
- Angles could be read off the top disc, which was scored with two lines crossing at right angles.
- The sighting and reading elements were made of bronze.
3. Roman Groma
- principal tool used by the Roman surveyors to trace on the ground simple and orthogonal alignments, necessary to the construction of roads, city, temples and agricultural lands subdivision.
Parts of Roman Groma
- Ferramento - a pole in hollow metal equipped in the inferior extremity with metallic cone-shape point for the fixing
- Stelleta - Cross arms fixed at right angles and pivoted eccentrically upon the ferramento
- Cornicula - extremities of the stelleta where plumblines are suspended
- Rostrum - a strong pole with the cylindrical extremities: one to receive the swivel pivot of the stelletta, the other for the grafting in the vertical pole; the distance among the two cylinders is exactly a foot (0.3048 m)
4. Libella
- Assyrians and Egyptians as first users
- A-frame with a plumb line suspended from its apex and used to determine the horizontal
- Horizontal foundations of the great pyramids of Egypt defined by libella
5. Merchet
- Device for measuring time and meridian
- First used by the Chaldeans (approx. 4000 B.C.)
- By sighting through the slot and past the plumb bob string, a straight line could be projected.
Parts of a Merchet
- a slotted palm leaf through which to sight
- bracket from which a plumb bob is suspended
Uses of Ancient Surveying Instruments
- Determine geographic coordinates
- Establish the horizontal
- Measure horizontal and vertical angular and linear distances
- Determine time and meridian
Recent Technologies
Total Station System
Digital Photogrammetry
Satellite Positioning System
◦ USA – NAVSTAR GPS
◦ Russia –GLONASS
◦ European Union –Galileo
Geographic and Land Information Systems
Recent Technologies
- Total Station System
- Digital Photogrammetry
- Satellite Positioning System
- USA – NAVSTAR GPS
- Russia – GLONASS
- European Union – Galileo
- Geographic and Land Information Systems
Uses of Survey
- Establishment of boundaries of land
- Fixing of national and state boundaries
- Charting of coastlines and navigable streams and lake
- Precise location of definite reference points throughout the country
- Collection of valuable facts concerning the earth’s
magnetism at widely scattered stations throughout the country
General Classifications of Surveys
- Plane Surveying
- Geodetic Surveying
- Plane Surveying
surveying in which the mean surface of the earth is
considered a plane, or in which its spheroidal shape is
neglected
- Geodetic Surveying
takes into account the true shape of the earth
Types of Surveying
- Control Survey
- Property Survey
- Topographic Survey
- Hydrographic Survey
- Mine Survey
- Route Survey
- Construction Survey
- Photogrammetric Survey
1. Control Survey
consists of establishing the horizontal and vertical positions of arbitrary points
2. Property Survey
performed to determine the length and direction of lot lines and to establish the position of these lines on the ground
3. Topographic Survey
made to secure data from which may be made a topographic map indicating the configuration of the terrain and the location of natural and human-made objects
4. Hydrographic survey
refers to surveying of bodies of water for the purposes of
navigation, water supply, or subaqueous construction
5. Mine Survey
utilizes the principles for land, geologic and topographic surveying to control, locate and map underground and surface works related to mining operations
- Route survey
refers to those control, topographic and construction surveys necessary for the location and construction of lines of transportation or communication, such as highways, railroads, canals, transmission lines and pipelines.
- Construction Survey
performed to lay out, locate and monitor public andprivate engineering works
- Photogrammetric Survey
utilizes the principle of aerial and terrestrial photogrammetry, in which measurements made on photographs are used to determine the positions of photographed objects.
Definition of Terms
(Level surface, Zenith, Nadir, Horizontal Plane, Line & Angle)
- Level surface – a curved surface every element of which is normal to a plumb line
- Zenith – direction away from the center of the earth and above the observer’s head
- Nadir – direction toward the center of the earth
- Horizontal plane- plane tangent to a level surface at a particular point
- Horizontal line – a line tangent to a level surface. In surveying, it is commonly understood that a horizontal line of sight is straight.
- Horizontal angle – an angle formed by the intersection of two lines in a horizontal plane.
- Vertical line – a line perpendicular to the horizontal plane; a vertical line in the direction toward the center of the
earth is said to be in the direction of the nadir. - Vertical plane – is a plane in which a vertical line is an element
- Vertical angle – angle between two intersecting lines in a
vertical plane - Zenith angle – angle between two lines in a vertical plane where it is understood that one of the lines is directed toward the zenith.
- Nadir angle – angle between two lines in a vertical plane
where it is understood that one of the lines is directed toward the nadir. - Grade/Gradient of a line – slope of the line or rate of ascent or descent
