Introduction to Geographic Information Systems (GIS).pptx
Download as PPTX, PDF•0 likes•328 views
This document provides an introduction to geographic information systems (GIS), including the key components and applications of GIS. It discusses that GIS allows users to capture, store, analyze and present spatial data to understand geographic patterns and relationships. The document outlines the history and evolution of GIS from early manual mapping techniques to modern digital systems combined with tools like remote sensing. It also summarizes the typical software, data types, and file formats used in GIS, highlighting how vector and raster data can be used to represent different types of geographic features and information.
Introduction to Geographic Information Systems (GIS).pptx
- 1. Introduction to Geographic Information Systems (GIS) Understanding the Basics and Applications
- 2. Learning outcomes:- • Introduction to GIS • Components of GIS • GIS Data Types • Applications of GIS • Software Involved in GIS
- 3. Introduction to GIS • Definition: GIS is a system designed to capture, store, manipulate, analyze, manage, and present spatial or geographic data. Importance: GIS is essential because it allows us to understand geographic data. (Spatial patterns, relationships, and trends) History: The evolution of GIS can be traced back to early cartography and manual map overlay techniques.
- 4. Evolution of GIS Early Developments: Before the advent of computers, maps were created manually using techniques like cartography and map overlay. • labor-intensive & limited in their analytical capabilities. Emergence of Computerized GIS: With the introduction of computers, GIS evolved into digital mapping and database systems. • The storage and manipulation of spatial data in electronic formats, making analysis more efficient. Modern GIS: Combined with Remote sensing, GPS, and spatial analysis tools. Remote sensing is the acquiring of information from a distance.
- 6. Software Components • ArcGIS: Developed by Esri, ArcGIS is one of the most widely used GIS software packages. It consists of multiple modules, including ArcMap for traditional desktop GIS • QGIS: is an open-source GIS software known for its user-friendly interface and extensive plugin ecosystem. It provides a wide range of features for data visualization, analysis, and editing. • GRASS GIS: is a free and open-source software suite for geospatial data analysis and management. It offers advanced capabilities for raster and vector data processing, as well as a command-line interface for scripting and automation. • Google Earth: is a web-based mapping service that allows users to explore geographic data in a 3D virtual environment.
- 7. Data Components • Spatial Data Types: Spatial data represents the geographic location and shape of features on Earth's surface. It can be categorized into vector data (points, lines, polygons) and raster data (grids of cells). • Attribute Data: Attribute data consists of descriptive information associated with spatial features. This can include attributes such as population density, land use classification, or soil types. • Sources of GIS Data: Remote sensing satellites, aerial surveys, GPS devices, field surveys, and government agencies.
- 9. Vector Data: • Points: Specific locations on Earth's surface, such as landmarks, buildings, or sampling sites. They are commonly used to store discrete data, such as the location of a city or the position of a tree. • Lines: linear features, such as roads, rivers, or pipelines. They are used to represent features that have length but negligible width, such as transportation networks or utility lines. • Polygons: Areas or regions on Earth's surface, such as land parcels, administrative boundaries, or land cover types. They are used to delineate boundaries and represent features with defined boundaries and shapes.
- 10. Raster Data: • Grid Structure: Organized into a grid of cells, with each cell representing a unit of space on Earth's surface. (Continuous phenomena, such as elevation or temperature, across a landscape) • Pixel Values: Each cell in a raster dataset stores a value representing a specific attribute or phenomenon. For example, in a digital elevation model (DEM), each cell stores elevation data, while in a land cover classification raster, each cell stores information about the land cover type present at that location. • Applications: Raster data is commonly used in remote sensing, digital terrain modeling, land cover mapping, and environmental modeling.
- 11. GIS Data Formats: • Shapefiles: Shapefiles are a common vector data format used in GIS. They consist of multiple files (.shp, .shx, .dbf, etc.) • GeoTIFF: is a raster data format that allows for the embedding of georeferencing information within the image file. This makes it possible to accurately locate and display raster data within a GIS environment. • KML (Keyhole Markup Language): KML is an XML-based file format used for representing geographic data in Google Earth and other mapping applications. • GeoJSON: is a lightweight data interchange format used for encoding geographic data structures. It is commonly used for web mapping applications.
- 12. Thank you