UTM to Latitude Longitude Conversion
Ø Convert UTM to Latitude – Longitude
- Open application and Select UTM Tab
- Select Map Datum
- Specify the Zone Number
- Click on ‘…’ Button if you want to refer to Datum number map
- Select the Hemisphere
- Enter Easting and Northing Values
- Click on Convert to Get Latitude and Longitude of the given point
- It is always better to convert latitude longitude with higher precision
Ø Convert Latitude Longitude to respective UTM
- Select ‘Lat / Long’ Tab
- Select Map Datum
- Specify Latitude and Longitude
- Click on Convert to get respective UTM coordinates
Convert from One Coordinate System to another Coordinate System in Bulk
Select ‘Bulk’ Tab
Ø Converting Bulk UTM
- Select ‘UTM’ Tab
- Click ON Open Template and Program will open an Excel Sheet
- Enter Bulk (Multiple / Many) UTM coordinates with Hemisphere and Zone Details
- Save the File
- Select Excel File by Locating the file after clicking ‘…’ Button
- Select the Map Datum
- Click on Convert
- The software will process bulk data at once and give the resulting Latitude and Longitude in Excel Sheet (Spread Sheet)
Ø Converting Bulk Lat Long (Latitude Longitude)
- Select ‘Lat/Long’ Tab
- Click on Open
- Click ON Open Template and Program will open an Excel Sheet
- Enter Bulk (Multiple / Many) Lat Long Values
- Save the File
- Select Excel File by Locating the file after clicking ‘…’ Button
- Select the Map Datum
- Click on Convert
- The software will process bulk data at once and give the resulting UTM Coordinates in Excel Sheet (Spread Sheet)
Converting Latitude Longitude into Map Coordinate is not a single step conversion as in most of the conversion from one unit to another unit by applying simple formula. This white paper explains which are the factors to be understood for Latitude and Longitude Conversion.
- Cartesian coordinate system (CCS)
- Geographic Coordinate Systems
- Geographic Directions
- Latitude
- Meridian
- Prime Meridian
- Longitude
- Geodetic Height
- Ellipsoid
- Map
- Map Datum
- Map projection
- Universal Transverse Mercator coordinate system
- UTM Zone
Cartesian coordinate system
A Cartesian coordinate system specifies each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances from the point to two fixed perpendicular directed lines, measured in the same unit of length. Each reference line is called a coordinate axis or just axis of the system, and the point where they meet is its origin, usually at ordered pair (0,0)
Earth is not a Flat Surface. So Cartesian coordinate system cannot be used to represent Earth Surface as Earth has a Spherical Surface. When survey is done for less then 10 Kms, variation due to curvature of the earth will be insignificant and flat earth models can be used. But when maps represent bigger area, Curvature of Earth has to be considered and hence there is a need of geographical coordinate system.
Geographical coordinate System (Global Coordinate Systems) (i.e., Latitude and Longitude values, in degrees)
For sufficient accuracy to allow global exploration, navigation and mapping earth is considered as spherical for Mathematical Modeling. Describing positions on the surface of the Earth in Latitude and Longitude are the most common representation of spatial data and is called Geographic Coordinate Systems.
Geographic Directions
North: Direction toward the North Pole.
South: Direction toward the South Pole.
East: The direction parallel to the Equator and toward which the Earth’s rotation is
West: The direction opposite to the Earth’s rotation is West.
Geographic Coordinates
Cartesian coordinates is a point defined by x and y (a pair of numbers) in a plane. Similarly, any point on the earth can be defined with a pair of numbers which are called geographic coordinates (latitude, Longitude) assuming that Earth is Sphere. These coordinates values are measured in degrees, and represent angular distances calculated from the center of the Earth.
Latitude and Longitude are the angles measuring North to South and East to West.
The Equator and Prime Meridian are the reference planes used to define latitude and longitude.
Equator
Since it is known form Ancient Greeks time that Earth is spherical object rather than a flat surface, to determine position on the Earth, reference points and circles are defined. Imaginary line passing through North Pole to South Pole is the Earth’s rotation axis. The circle perpendicular to this axis which is equidistant from the poles is known as Equator. Equator is the starting point for measuring latitude.
Latitude
Any circle parallel to the Equator is called a parallel of latitude. Multiple circles or approximation of a circle on the surface of the Earth, parallel to the Equator are called latitude lines.
Meridian
An imaginary arc on the Earth’s surface from the North Pole to the South Pole is known as Meridian.
Prime Meridian
The meridian of Royal Observatory in Greenwich, England, is the internationally accepted as Longitude of 0 degrees. It is the reference that is used as the origin for the measurement of longitude. Prime Meridian is the starting point for measuring Longitude.
Anti-Meridian
It is another portion of the meridian line exactly opposite to the Prime Meridian. Note that the anti-meridian can be described by either 180° west longitude or 180° east longitude.
Longitude
Lines of longitude, called meridians, run perpendicular to lines of latitude, and all pass through both poles.
The Earth is divided equally into ±90° degrees of latitude and ±180° degrees of longitude.
Latitude Measurement
There is 90° of Latitude from Equator moving towards north pole and similarly 90° South Latitude Passes through South Pole. One degree of latitude at the Equator also corresponds to 111 Km (111,319.9 m).
Longitude Measurement
There are 180 degrees of longitude to the east of the Prime Meridian. There are also 180 degrees of longitude to the west of the Prime Meridian. Western longitudes are often expressed as negative values, particularly in computer applications. One degree of longitude at the Equator also corresponds to 111 Km (111,319.9 m). It gets progressively smaller as one moves towards the poles, eventually shrinking to zero.
Minutes and Seconds of Arc
A degree of latitude or longitude is relatively large, so it is necessary to break them down into smaller units. So Latitudes and Longitudes are represented as Degree, Minute and Second.
1 Min = 1/60 of a Degree and 1 Sec = 1/60 of a Minute
A minute of arc corresponds to 1.86 Km. A second of arc corresponds to 31.0 m.
Decimal Degrees (DD): Latitude and Longitude geographic coordinates are represented as decimal fractions and are called Decimal Degrees.
10 Degree 12 Minute 14 Seconds is represented as 10o 12 ‘ 14 “ = 10 + 12 / 60 + 14 / 3600 = 10.20389
Geodetic Height
The geodetic height at a point is the distance from the reference sphere to the point in a direction normal to the sphere.
Earth has substantial variations in the elevation of its surface from point to point.
The peak of Mt. Everest is 9 Km above sea level and The deepest point of the Marianna Trench is 11 Km below sea level.
Ellipsoid
Precise measurements show that equatorial diameter is 12,756 Km and polar diameters of the Earth is 12,713 Km, a difference of only 43 Km. So earth is not round either. It is flattened at the poles. It is an oblate ellipsoid, like a squashed beach ball. It resembles a three dimensional ellipse called an ellipsoid. An ellipsoid can be defined by a number of mathematical characteristics.
If the surface of the earth has to be represented as a Map (2 – Dimension) then we need to project points into 2 dimensional Space and since earth is not a perfect spear (perfect round) Ellipsoid representation to be used for mathematical modeling. Map coordinates are usually shown in one of two ways, as geographical coordinates (ie latitude and longitude values, in degrees) or grid coordinates, (as easting and northing values, in metres).
Spherical models fail to model the actual shape of the earth. The slight flattening of the earth at the poles results in about a twenty kilometer difference at the poles between an average spherical radius and the measured polar radius of the earth. Ellipsoidal earth models are required for accurate range and bearing calculations over long distances.
Map
For many purposes it’s much more useful to represent the Earth on a flat surface, such as paper or a computer screen. Such a flattened representation of the Earth is called a map.
Map Datum
A datum is a mathematical model which approximates the shape of the Earth. It allows calculations such as position and area to be done in a consistent and accurate manner.
Because there are different ways to fit the mathematical model to the surface of the Earth, there are many different datums used around the world today depending on Nation and Agencies. Cartography, surveying, navigation, and astronomy all make use of geodetic datums
Simple Datum Models(Flat-earth models) are used for plane surveying
Complex Datum models used for international applications which completely describe the size, shape, orientation, gravity field, and angular velocity of the earth.
It is essential to select proper datum to get better level of accuracy. The Global Positioning System uses an earth centered datum called the World Geodetic System 1984 or WGS 84. The WGS 84 is currently one of the most widely used datums around the world. The WGS-84 Geoid defines geoid heights for the entire earth.
Note: Coordinate values resulting from interpreting latitude, longitude, and height values based on one datum as though they were based in another datum can cause position errors in three dimensions of up to one kilometer.
Different datums are based on different mathematical models of the earth’s shape and dimensions (ELLIPSOIDS) plus an additional factor of PROJECTION.
Map projection
Map Projection is a method of representing the surface of a sphere on a plane.
To view the Earth on a flat piece of paper or a computer screen, its curved surface must be projected. A projection is a process which uses the latitude and longitude which has already been ‘drawn’ on the surface of the Earth using a datum, to then be ‘drawn’ onto a map.
By definition, all map projections show a distorted representation of the Earth surface therefore different map projections exist in order to preserve some properties of the sphere-like body (ie. either area, shape, direction, bearing, distance and/or scale) at the expense of other properties.
Universal Transverse Mercator coordinate system
Universal Transverse Mercator (UTM) PROJECTION touches the earth at various LONGITUDES called Central Meridans and uses a projection point at the center of the earth.
The Universal Transverse Mercator (UTM) geographic coordinate system uses a 2-dimensional Cartesian coordinate system to give locations on the surface of the Earth. It is a horizontal position representation, i.e. it is used to identify locations on the Earth independently of vertical position, but differs from the traditional method of latitude and longitude in several respects.
UTM Zone
The UTM system is not a single map projection. UTM divides the Earth into sixty zones, each a six-degree band of longitude, and uses a secant transverse Mercator projection in each zone.
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Theory behind converting CAD Drawing to KML
Extract Elevations from Google Earth (Free)
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 UTM_Converter.exe |
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