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n Geographic Information System is computer based tools that facilitate mapping and spatial analysis of earth’s features and events.
n Simply it is a table + its map.
n GIS enable you display your information as maps, which is easy to read for everyone.
n Reveal hidden patterns in geographic data bases that is impossible to reveal using traditional statistical packages.
n Vector Data :
The unit block of this type of data is the points, connecting two points create a line , enclosing a line creates a polygon.
n All GPS data is a vector data , when speaking about vector data we speak about precision.
n Political boundaries.
n Streets.
n Animal routes.
n Grazing type.
n cities. And towns( depending on scale , as points or polygons.)
n Rivers (depending on scale , lines or polygons.)
Raster Data:
This is the type of data getting from satellite images, the unit block of this data is the pixel.
speaking about raster data is speaking about resolution .
n Spatial resolution.
n Spectral resolution.
n Temporal resolution.
n Radiometric resolution.
n The raster model is best in representing fields “ continuous space”
n Examples are :
n Elevations.
n Slopes.
n Ozone, or carbon dioxide concentration.
n Temperature and rainfall.
n Etc…
n Those are the tables containing the descriptive information for the spatial data.
n So what you want to link to your location is possible .
n It is better to hold it in dbf formats.
n Boolean. (yes/no). E.g the presence or absence of a disease.
n Nominal. ( identification)
n Ordinal. ( low , med , high)
n Interval. E.g temperature where subtraction make a meaning.
n Scalar.
n Suppose you are registering a location of an animal farm , what you are going to register.
n Personal data , owner name.
n Number of animals .
n Management strategies.
n Hygienic perspectives followed.
n Vaccination.
n Determine and illustrate change through time.
n Index and retrieve material by spatial and temporal location.
n Analyze and present spatial and temporal information.
n Mapping quantities and categories.
n Mapping hot spots and disease occurrences.
n Mapping the risks.
n GIS is useful in displaying hidden patterns of tables and DBs.
n It allows you to create detailed and intelligent maps.
n It allow you to integrate different geographic data to reveal trends and relationships.
n Mapping things as they occur or even you can predict how they will occur.
منتصر محمد عبدالله
ساحة النقاش