Geography Information System (GIS)
A Geography information system (GIS) is a framework for gathering, managing and analyzing data. Rooted in the science of geography, GIS integrates many types of data. It analyzes spatial location and organizes layers of information into visualizations using maps and 3D scenes. With this unique capability, GIS reveals deeper insights into data, such as patterns, relationships and situationsusers make smarter decisions.
What is GIS
Hundreds of thousande of organization in virtually every filed are using GIS to make maps the at communicate, perform analysis, share information, and solve complex problems around the world. This is changing the way the world works.
How GIS woks
GIS technology applies geographic science with tools for understanding and collaboration. it helps people reach a common goal: to gain actionable intelligence from all types of data.
Maps
Maps are the geographic container for the data layers and analytics you want to work with GIS maps are easily shared and embedded in apps and accessible by virtually everyone, everywhere.
Data
GIS integrates many different kind of data layer using spatial location. Most data has a geographic component. GIS data includes imagery, feature and base maps linked to spreadsheets and tables.
Analysis
Spatial analysis lets you evaluate suitability and capability, estimate and predict, interpret and understand and much more, lending new perspective to your insight and decision - making.
Apps
Apps provide focused user experience for getting work done and bringing GIS to life for everyone. GIS apps work virtually everywhere: on your mobile phones, tablets, in web browsers and on desktops.
Geo is Nothing But, geo is Earth...
What is map:
cartographer:
Types of maps:
1). Physical (or) Relief maps:
2). Political maps:
3). Thematic maps:
what is a map Legend?
A map Legend is included with a map to unlock it. it gives you the information needed for the to make sense. map often use symbols (or) colors to represent things and the map legend explains what they mean. symbols in the legend might be pictures (or) icons that represent different things on the map.
What is Geo mapping?
Type Of Images File Format:
What is JPEG file?
What is TIF file?
What is GIF file?
What is PNG?
Disadvantages_ Normally unable to reach JPEG file reduction (10mb-11mb)
What is EPS file?
What is Shape file?
Geography Information System(GIS)
Geography information system are computer based systems that can deal with virtually any type of information about features that can be referenced by geographical location. These systems are capable of handling both locational data and attribute data about such features. That is, not only do GIS permit the automated mapping (or) display of the location of Features, but also these systems provide a capability for recording and analyzing descriptive Characteristics about the features. For example, a GIS might contain not only a ‘map’ of the locations of road but also a database of descriptors about each road. These ‘attributes’ might include information such as road width, pavement type, speed limit, number of traffic lanes, data of construction, not so on. Table 1.1 lists other examples of attributes that might be associated with a given point, line, or area feature.
Much of the power of a GIS comes from the database management system (DBMS) that is designed to store and manipulate these attribute data. Many GISs employ a relational database, consisting of tables, or ‘relations’, with attributes in columns and data records, or ‘tuples’ in rows (Example-1.1).
(Example-1.1)
Example-1.1 point, line, and area features and typical attributes contained in a GIS.
Point feature well (depth, chemical constituency). Line feature power line (service capacity, age, insulator type). Area feature soil mapping unit (soil type, texture color, permeability).
The above example illustrates the GIS analysis function commonly referred to as overlay analysis. The number, from, and complexity of other data analysis possible with a GIS are virtually limitless. Such procedures can operate on the system’s spatial data, the attribute data, (or) both. For example, aggregation is an operation that permits combining detailed map categories to create new, less detailed category (e.g., combining “jack pine” and “red pine” categories into a single “pine” category). Buffering creates a zone of specified width around one (or) more features (e.g., the area within 50 m of a stream). Network analysis permits such determinations as finding the shortest path through a street network, determining the stream flows in a drainage basin, (or) finding the optimum location for a fire station. Intervisibility operations use elevation data to permit viewshed mapping of what terrain features can be “seen” from a specified location. Similarly, many GISs permit the generation of perspective view portraying terrain surface from a viewing position other than vertical.
Several constraints need to be considered when combining data from multiple sources in a GIS, as in the example illustrated in figure 1.25 Obviously, all of the data layers must cover the same geographic area, (or) at least partially overlap. An equally important consideration is that the data layers must share the same geographic cording system. While a GIS can convert data from one coordinate system to another, it is necessary for the user to understand the characteristics of the various types of coordinate systems that may be used.
What is GIS? (Definition)
A computer system that can be used to
storage view process analyst manage and
integrate geographic information.
Application:
What is GIS data?
Spatial Data:
where is it?
Attribute Data:
what is it?
Attribute Data: Information
Storage the geographic information by a table which connected to different features.
GIS Data:
Vector data consists of individual points, which (for 2D data) are stored as pairs of X.Y co-ordinates. The point may be joined in a particular order to create lines, (or) joined into closed rings to create polygons. (Point, Line, Polygon)
There are three main vector data ty/pes in GIS are:-
Vector Data:
Point:
Generally they are a latitude and longitude with a spatial reference frame. when features are too small to be represented as polygons. points and used.
Line:
vector lines connect each vertex with with paths.
Basically, you're connecting the dots in a set order and it becomes a vector line with each dot representing a vertex.
Polygon:
when you join a set of vertices in a particular order and close it, this is now a vector polygon feature.
Raster data:
The Raster data is made up of pixel has an associated value. simplifying slightly a digital photograph is an example of a raster dataset where each pixel value corresponds to a particular color.
in GIS, the pixel values may represent elevation above sea level (or) chemical concentration (or) rainfall etc...
There are five main raster data types in GIS are:-
satellite imagery are image of the earth or other planets collected by imaging satellites operated by government and businesses around the world. such data are recorded in raster format.
A binary image is one that consists of pixels that can have one of exactly two colors, usually black and white. Binary image also called bi-level or two-level. This means that each pixel is stored as a single bit- i.e., ao or 1.
Graphic File:
Digital Elevation Models:
Digital Orthophotos:
Vector Files Modal:
Shape file:
Coordinate system:-
Ex: WGS 1984 ITRF 2008.
Geographic coordinate system:
Latitude:
Projected coordinate system:
A projected coordinate system is
expressed the location on three dimensional by a flat two dimensional surface
which causes distortion in the shape area distance or direction of the data.
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