Family of cylindrical map projection

Family of Cylindrical Map Projection

Nisa Manzoor Nasir Mughal

TopicSimple Cylindrical Map Projection

Cylindrical Equal area Projection

Mercator’s Projection / Cylindrical Orthomorphic Projection

Transverse Mercator’s Projection(also called UTM)

ProjectionIs the science of converting the

spherical earth surface to a flat plane.

Define the spatial relationship between locations on earth and their relative locations on a flat map.

1. Cylindrical◦ Easy to use◦ Latitude and longitude

are at right angles◦ Shows true direction◦ Distorts high latitudes

2. Planar◦ Useful for showing

polar regions◦ Distorts direction and

distance

3. Conic◦ Good for showing a

small area accurately

Three Types of Map Projection

Simple Cylindrical Map Projection

Properties1. All parallels & meridians are straight lines.2. The meridians intersect the parallels at right angles.3. The distances between the parallels & meridians remain the same

throughout the projection.4. Length of all the parallels is equal to the length of the equator.5. The length of the equator on this projection is equal to the length of

the equator on the globe.6. The projection is neither equal-area nor orthomorphic.

Merits: Simple, Scale along equator & meridians is correct

Demerits: Scale along parallel away from the equator is exaggerate.

It is neither equal-area nor orthomorphic.

uses: For narrow belt along the equator

Cylindrical Equal-area Projection

Properties1.All parallels & meridians are straight lines.2.The meridians intersect the parallels at right angles.3.The distances between the parallels decreasing, but distances between the meridians increasing.4.The scale of parallels increases and that of meridians.5.It is an equal-area projection.6.It is not useful for polar areas because the shape is too much distorted near the poles.

Merits: Correct impression, showing good distributions of characteristics

Demerits: It is not useful for polar areas because the shape is too much distorted near the poles

Uses: for distribution maps of tropical countries & especially for tropical products

Mercator’s projectionA projection of a map that all the parallels of latitude have the same length as the equator, used especially for marine charts and certain climatological maps.

Properties:1. All parallels & meridians are straight lines.2. The meridians intersect the parallels at right angles. 3. The distances between the parallels increasing, but distances between the

meridians remain the same.4. Length of all the parallels is same & is equal to the length of the equator.5. The meridians are longer than the corresponding meridians on the globe.6. At a point, the scale along the meridian is equal to the scale along the

parallel. Therefore the projection is also called “Orthomorphic Projection”

Merits: Direction and shape are accurate Demerits: Polar areas cannot be shown due to the exaggeration of

parallels & meridians.

Uses: For navigational purposes in sea & air. Ocean currents, wind directions & pressure systems are shown on this projection due to its true

directions. For showing tropical countries for general purposes.

Mercator’s Projection / Cylindrical Orthomorphic Projection

Rhumb LineAn imaginary line on the earth's surface cutting all meridians at the same angle.

Straight lines represent lines of constant bearing on the real sphere. These straight lines are called loxodromes/ rhumb line.

The Universal Transverse Mercator projected coordinate system uses a 2-dimensional Cartesian coordinate system to give locations on the surface of the Earth. It is a horizontal

position representation.

Universal Transverse Mercator UTM

Derivation of UTMUTM derives from Standard and Transverse Mercator, both projections are cylindrical, which are given below.1. Standard (or Normal) Mercator2. Transverse Mercator

Standard MercatorAxis of the cylinder coincides with the polar axis and the line of tangency with the equator.

Transverse MercatorThe axis of the cylinder lies in the equatorial plane, and the line of tangency is any chosen meridian.

Properties1. ShapeConformal, Accurate representation of small shapes. Minimal distortion of larger shapes within the zone.2. AreaMinimal distortion within each UTM zone. 

3. DirectionLocal angles are true.

4. ArcGISDefine a projection Project a shape file or grid to a new projection.Change the projection for display and Calculation.

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