Babylonians had without competition. In a simple the cubit, the Flemish ell, the English ell, the French ell, the way, a contemporary unit such as meter, is divided according fathom, the hand, and the foot. The realization of the position in the two angular quantities latitude and longitude, where each of them is defined by three quantities in sexagesimal numbering system, is not easy for arithmetic operations, so this realization is converted to the decimal system, as the known quantity decimal degree.

## Use of GIS Mapping as a Public Health Tool—From Cholera to Cancer

The coordinates of Khufu pyramid can be represented as decimal degrees, so it will have north latitude of If a person moved from the great pyramid point P a distance of 0. This position when converted Figure 2. The ellipsoid is the best geometrical shape that fits the geoid, which is the real shape of earth. Classically, the earth latitude is divided into 90 degrees between Equator and North Pole, and also 90 degrees between Equator and South Pole.

The earth longitude is divided into degrees east Greenwich line, and degrees west Greenwich line. This earth grid of one degree size has variable length from KM side length at Equator to 79KM at latitude 45, to zero at pole as shown in Figure 3. Figure 4. Khufu Pyramid in Giza, Egypt.

The red point P and yellow point B are expressed in classical geographic coordinates: degrees, minutes, and seconds, and in decimal degrees. The sketch at the right depicts the geometry between two points Satellite image from Quickbird One of the reasons of using map projection instead of Figure 3. The users of Mobile GIS require easy to use metric system for their continuous geospatial activities Gouveia et al. The use of degrees based on sexagesimal system The latitude or longitude on earth surface is defined as is facing difficulties in mobile GIS industry, and many mobile three quantities, which are degrees, minutes, and seconds, and devices do not display coordinates for the user, instead they most often parts of the second, as an example, the south- display the relative position on background raster map.

Also, the proposed technological aspect in its early start in the mid of the 20th metric system has to define a single unit and quantity for the century when Tomlin established the Canadian Geographic latitude and longitude without need of conversion when used in Information System, to a stable scientific discipline in the start calculations and in the same time easy for oral and written of the third millennium Goodchild , The advent in communication by normal user. In the same time, 6. The accuracy of standalone GPS equipments is in advent in positioning techniques and mobile devices, enabled continuous enhancement.

These advancements require a modern metric system for geographic coordinates that is easy to use and display for users, unified and seamless over TABLE II. In the example of Khufu pyramid, the accuracy of the GPS standalone receiver which is in the range coordinates of point P can be expressed as 1,, Table III shows the variation of the distance on and 1,, These numbers looks hard the earth ellipsoid relative to latitude value.

The position of point B will be accuracy than 1 second, this is obvious because it divides the 1,, The change in minutes to parts more than the 60 parts of the seconds.

## Dynamic and Mobile GIS: Investigating Changes in Space and Time (Innovations in GIS)

If coordinates appeared in the first digit after decimal point. In the previous example of great pyramid, the position P in minutes coordinates will be realized as Each quantity is composed of 4 digits and two digits after the decimal point. The number is easy to use by normal users, and it has nominal accuracy of 20m which is accepted for navigation purposes and daily use of mobile GIS.

If the use of degrees is changed to minutes as the essential quantity for geographic coordinates, and seconds are converted Figure 6. The coordinates of Khufu Pyramid expressed in degrees, minutes, to decimals of minutes. This solution will define the latitude seconds and decimal degrees with nominal accuracy of 20m.

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Figure 5. The coordinates of Khufu Pyramid expressed in proposed minutes system.

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In order to use this system for surveying, it requires to have millimeter accuracy for surveying works which need high accuracy. Geographical information science: fifteen years later. Fisher, Ed. The conventional sexagesimal system for geographic the International Journal of Geographical Information Science and coordinates is more than 5, years old, and is not suitable to Systems.

The proposed metric system for geographic [3] Goodchild, M. International coordinates based on minutes only with two decimal digits has Journal of Geographical Information Systems 6 1 : The [4] Gouveia, C.

Citizens proposed milli-minute metric system with four decimal digits is as Mobile Nodes of Environmental Collaborative Monitoring Networks. The book examines challenges to security and privacy and presents practical solutions to these problems while focusing on modeling approaches and exploring the need to display an appropriate level of information in a mobile environment.

Concluding with a study of mobility, the book also contains practical examples of applications of mobile devices for disaster management and environmental monitoring. The book also looks to the future, investigating important research directions and potential challenges. Log In. My Account.

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## Dynamic and Mobile GIS

Dynamic and mobile GIS : investigating changes in space and time. Conference Author:. Publication Information:.

Subject Term:. Geographic information systems.