GS (Leveling, Lesson 6)

21問 • 1年前

問題一覧

process of directly or indirectly measuring vertical distances to determine the elevation of points or their differences in elevation

Leveling

the equipotential surface of the earth’s gravity field.

Level Surface

curved line in a level surface all points of which are normal to the direction of gravity and equidistant from the center of the earth

Level Line

curved line in a level surface all points of which are ______ to the direction of gravity and _______ from the center of the earth

normal, equidistant

plane that is tangent to a level surface at a particular point

Horizontal Surface

straight line in a horizontal plane which is tangent to a level line at one point.

Horizontal Line

line parallel to the direction of gravity

Vertical Line

vertical distance between the two level surfaces in which the points lie

Difference in Elevation

imaginary surface of the sea which is midway between high and low tides

Mean Sea Level

any convenient level surface coincident or parallel to mean sea level to which elevation of a particular area are referred

Datum

Types of Leves

Dumpy Level, Hand Level, Builder's Level, Wye Level, Automatic Level, Tilting Level, Transit as a Level, Laser Level

most widely used direct leveling instrument

Dumpy Level

very identical to the dumpy level

Wye Level

used in setting of concrete forms, batter boards, and establishing grades of earthworks.

Builder's Level

particularly useful where the ground is soft or when strong winds blow against the instrument since it can automatically relevel itself.

Automatic Level

“the universal surveying instrument”

Transit as Level

commonly employed for very precise leveling operations and in other general leveling work.

Tilting Level

Example of Instrumental Errors

Instrument Out of Adjustments, Rod Not Standard Length, Defective Tripod

Example of Personal Errors

Bubble Not Centered, Parallax, Faulty Rod Reading, Rod Not Held Plumb, Incorrect Setting of Target, Unequal Foresight and Backsight Distances

Examples of Natural Errors

Curvature of Earth, Atmospheric Refraction, Temperature Variation, Wind, Settlement of Instruments, Faulty Turning Points

Mistakes in Levelling

Misreading the Rod, Incorrect Recording, Erroneous Computation, Rod Not Fully Extended, Moving Turning Points

carto

carto

Mesozoic Era

Mesozoic Era

Mesozoic Marine Life and Dinosaurs

Na Me · 26問 · 1年前

Mesozoic Marine Life and Dinosaurs

Cenozoic

Cenozoic

RA 8371 (CHAPTER 1 & 2)

Na Me · 20問 · 1年前

RA 8371 (CHAPTER 1 & 2)

20問 • 1年前

Na Me

RA 8371 (CHAPTER 3 & 4)

Na Me · 15問 · 1年前

RA 8371 (CHAPTER 3 & 4)

RA 8371 (NCIP)

RA 8371 (NCIP)

GS (TOPOGRAPHY)

GS (TOPOGRAPHY)

GS (CONTROL SURVEY)

GS (CONTROL SURVEY)

Hydrography

Hydrography

GEO 124 LEC 1

GEO 124 LEC 1

COMA

COMA

GS 2 Control Survey

GS 2 Control Survey

GS 2 - Control Survey

Na Me · 8問 · 1年前

GS 2 - Control Survey

8問 • 1年前

Na Me

Hydrography (Lesson 2)

Na Me · 26問 · 1年前

Hydrography (Lesson 2)

HYDRO (LEC 3)

HYDRO (LEC 3)

Law (Lecture 1)

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GS 2 (Lec 1 & 2)

GS 2 (Lec 1 & 2)

COMA

COMA

問題一覧

process of directly or indirectly measuring vertical distances to determine the elevation of points or their differences in elevation

Leveling

the equipotential surface of the earth’s gravity field.

Level Surface

curved line in a level surface all points of which are normal to the direction of gravity and equidistant from the center of the earth

Level Line

curved line in a level surface all points of which are ______ to the direction of gravity and _______ from the center of the earth

normal, equidistant

plane that is tangent to a level surface at a particular point

Horizontal Surface

straight line in a horizontal plane which is tangent to a level line at one point.

Horizontal Line

line parallel to the direction of gravity

Vertical Line

vertical distance between the two level surfaces in which the points lie

Difference in Elevation

imaginary surface of the sea which is midway between high and low tides

Mean Sea Level

any convenient level surface coincident or parallel to mean sea level to which elevation of a particular area are referred

Datum

Types of Leves

Dumpy Level, Hand Level, Builder's Level, Wye Level, Automatic Level, Tilting Level, Transit as a Level, Laser Level

most widely used direct leveling instrument

Dumpy Level

very identical to the dumpy level

Wye Level

used in setting of concrete forms, batter boards, and establishing grades of earthworks.

Builder's Level

particularly useful where the ground is soft or when strong winds blow against the instrument since it can automatically relevel itself.

Automatic Level

“the universal surveying instrument”

Transit as Level

commonly employed for very precise leveling operations and in other general leveling work.

Tilting Level

Example of Instrumental Errors

Instrument Out of Adjustments, Rod Not Standard Length, Defective Tripod

Example of Personal Errors

Bubble Not Centered, Parallax, Faulty Rod Reading, Rod Not Held Plumb, Incorrect Setting of Target, Unequal Foresight and Backsight Distances

Examples of Natural Errors

Curvature of Earth, Atmospheric Refraction, Temperature Variation, Wind, Settlement of Instruments, Faulty Turning Points

Mistakes in Levelling

Misreading the Rod, Incorrect Recording, Erroneous Computation, Rod Not Fully Extended, Moving Turning Points