Geographic Data Types, Sources & Representation PDF

Geographic data: types, sources, Methods of representing them Geographical data Types Definition of spatial data Definition of metadata Spatial data sources Metadata sources Methods of Representing Data "Maps" Geographical data Metadata is non-spatial data related to the spatial element that is...

Geographic data: types, sources, Methods of representing them Geographical data Types Definition of spatial data Definition of metadata Spatial data sources Metadata sources Methods of Representing Data "Maps" Geographical data Metadata is non-spatial data related to the spatial element that is distributed on the map in the form of a point, line, or Polygon. It is data that describes the elements of the map. Metadata Spatial Data Spatial Data is the spatial element that is distributed on the map in the form of a point, line, or Polygon. For example, if a hotel is represented as a point on a map, the Metadata of this point is the characteristics associated with the hotel, such as the number of floors, the number of rooms, the name of the hotel, the level of service, and the hotel address. Each point has a coordinate (X, Y), such as services: “schools, hospitals, police stations, fire stations.” For example, if a road is represented as a line on a map, the Metadata of this line is the name of the road, its width, type. A single line has a pair of coordinates, its beginning and its end. Such as roads, railways, and political borders. For example, if a region is represented as a polygon on a map, the Metadata of this polygon is the name of the region, the type of land exploitation in it, the number of inhabitants in it, the type of crops grown in it, and the type of terrain distributed in it. The region has coordinates for all its corners. Such as buildings, agricultural lands, and the Emirates. Spatial data sources It is the oldest and most common method of raising the features of the Earth’s surface. It aims to calculate the levels of points, the distances between them, the horizontal and vertical angles, calculate the deviations of the sides that connect the points, and extract coordinates using the Total Station device. It requires a long time and a lot of effort to monitor, record, calculate, and extract results. Aerial photography is the process of photographing the Earth’s surface through a regular camera installed in an aircraft flying at a known altitude (no more than 3,000 meters above the sea level). Satellite images (also Earth observation imagery, spaceborne photography, or simply satellite photos). Satellite imagery refers to images of the Earth taken from satellites orbiting the planet. These satellites are equipped with various sensors for detecting visible light, infrared light, microwave radiation, and more to craft highresolution images. It is collected by imaging satellites operated by governments and businesses around the world. The two famous types of Satellite images are Landsat and Sentinel. The Global Positioning System (Global Positioning System) is a satellite navigation system that provides information about location and time in all weather conditions anywhere on or near the Earth. It is available in multiple forms: a GPS station, and a GPS device. GPS that is found on mobile devices, such as the one we use daily, Google Maps. Metadata sources Obtaining it requires dealing directly with the phenomenon, such as conducting personal interviews or conducting questionnaires. These are the sources that can be obtained without directly dealing with the phenomenon, such as collecting data from internationally approved official censuses and from governmental and non-governmental departments and agencies. Methods of Representing Data 0n "Maps" point Relative circuit maps Give each position a geometric symbol Give each position a pictorial symbol line 1. isopleth maps, such as temperature, pressure, and contour lines 2. Migration maps Polygon Choropleth Maps : A specific but gradual color Point maps If a polygon is represented qualitatively, each polygon takes a different color Thank you