GIS (Geographic Information Systems) is a computer-aided mapping technique used to manage and analyze geographic data. GIS allows users to visualize, map, and print data collected from surveys, aerial photos, terrain analysis, and other sources.
The article describe about the basics of geographic information system (GIS) all its aspects, uses and resources.
What Is Geographic Information Systems (GIS)
Geographic Information Systems (GIS) a tool that allows users to capture, store, manipulate, analyze, and visualize spatial data, or data that has a geographic component.
GIS can be used to create maps and analyze data in relation to location, such as for land use planning, natural resource management, and infrastructure planning.
It can also be used for a wide range of application such as urban planning, transportation, criminology, marketing, environmental management, and many more.
GIS software allows users to overlay different types of data, such as satellite imagery, demographic data, and weather data, to gain insights and make informed decisions.
Basics of Geographic Information Systems
How Does GIS Work?
GIS, or Geographic Information Systems, is a technology used for capturing, storing, manipulating, analyzing, and visualizing geographic data.
The process of using GIS typically involves the following steps:
Data acquisition: This step involves obtaining geographic data from various sources, such as satellite imagery, maps, and surveys.
Data preparation: Once the data is acquired, it needs to be cleaned, formatted, and prepared for analysis.
This step can include tasks such as removing errors, filling in missing data, and projecting the data onto a consistent coordinate system.
Data analysis: This step is where the real power of GIS comes into play. GIS software allows users to perform spatial analysis on the data, such as finding patterns, identifying trends, and making predictions.
Data visualization: The final step is to present the results of the analysis in a visual format, such as maps, charts, and graphs.
This step can include creating 3D models and animations, as well as creating interactive web maps.
Data management: GIS software also provides the ability to manage and organize data in a variety of ways, such as creating, editing, and querying spatial data.
Data sharing: GIS also provides the ability to share data and collaborate with other users.
This includes the ability to share maps and data over the internet and work together on spatial analysis projects in real-time.
GIS Data Types
There are several different types of data that can be used in GIS, including:
Vector data: This type of data is made up of points, lines, and polygons, and is used to represent things like roads, buildings, and political boundaries.
Vector data can be stored in a variety of file formats, such as shapefiles and geodatabases.
Raster data: This type of data is made up of a grid of cells, each containing a value. Raster data is used to represent things like satellite imagery and digital elevation models.
Raster data can be stored in a variety of file formats, such as TIFF and GeoTIFF.
Vector Data Vs Raster Data
Vector data and raster data are two different types of data used in GIS. The main differences between the two are:
Representation: Vector data is represented by points, lines, and polygons, while raster data is represented by a grid of cells, each containing a value.
Vector data is well suited for representing things like roads, buildings, and political boundaries, while raster data is well suited for representing things like satellite imagery and digital elevation models.
Resolution: Vector data has a higher level of precision and accuracy than raster data. Vector data points can be precisely located, while raster data is limited by the resolution of the grid of cells.
Size: Raster data can be quite large in file size, as it contains a lot of information. Vector data is typically smaller in file size, as it only contains the coordinates of the points, lines, and polygons.
Scalability: Vector data can be easily scaled up or down without losing quality, while raster data can become pixelated and lose detail when scaled.
Data types: Vector data is well suited for discrete data, such as political boundaries and land use. Raster data is well suited for continuous data, such as elevation, temperature and precipitation.
Analysis: Vector data is more suitable for geometric analysis and topological analysis, while Raster is more suitable for image processing and surface analysis.
It’s important to note that both Vector and Raster have their own advantages and disadvantages, choosing one over the other depends on the specific use case and the data available.
Stages of Geographic Information System
The stages of a Geographic Information System (GIS) can generally be divided into five main phases:
Planning and Feasibility
In this stage, the problem or opportunity that the GIS is being developed to address is identified, and the feasibility of using a GIS to solve the problem is determined.
This stage also includes developing a project plan, identifying the data and resources needed, and determining the scope of the project.
Data Acquisition and Management
In this stage, the data needed for the GIS is collected, acquired, and managed. This includes digitizing paper maps, acquiring satellite imagery, and collecting field data.
The data is then cleaned, standardized, and organized in a way that makes it useful for the GIS.
Data Analysis and Modeling
In this stage, the data is analyzed and modeled to extract useful information and knowledge.
This includes creating maps, performing spatial analysis, and building models to test hypotheses.
Implementation and Deployment
In this stage, the GIS is implemented and deployed. This includes installing and configuring the GIS software, training users, and making the GIS available to users.
Maintenance and Updating
In this stage, the GIS is maintained and updated to ensure that it continues to be useful and accurate.
This includes updating the data, fixing bugs, and making improvements to the GIS as needed.
Files Used GIS Data Management
There are several different types of files that are commonly used in GIS data management:
Shapefiles: A vector data file format commonly used to store geographic data, such as points, lines, and polygons.
Shapefiles are composed of three main files: a .shp file containing the geometry, a .dbf file containing the attributes, and a .shx file containing the index.
Geodatabases: A database file format used to store and manage large amounts of geographic data, including both vector and raster data.
Geodatabases are often used to store data for large-scale GIS projects, and can be created using software such as ArcGIS.
TIFF and GeoTIFF: Raster data file formats commonly used to store satellite imagery, digital elevation models, and other types of raster data.
TIFF files can store multiple images in a single file, while GeoTIFF files include georeferencing information.
CSV: A simple text file format used to store tabular data, such as population data and crime statistics.
CSV files can be opened and edited in a variety of programs, such as Microsoft Excel and Google Sheets.
KML and KMZ: Keyhole Markup Language, a file format used to store geographic data in a format that can be displayed in Google Earth and other mapping applications. KMZ is a zipped version of KML.
GML: (Geographic Markup Language) is an XML-based file format used to store geographic data in a way that can be easily shared and exchanged between different GIS systems.
It is an international standard for geographic information established by Open Geospatial Consortium (OGC).
Worldwide GIS Resources
Here is a list of some GIS resources that are available worldwide:
OpenStreetMap: A global, collaborative map of the world that is free to use and edit, and is often used as an alternative to proprietary maps.
Natural Earth: A public domain map dataset that includes detailed information about countries, oceans, rivers, and other features.
USGS Earth Explorer: A search and discovery platform for USGS satellite imagery, aerial photography, and other types of data.
GeoCommons: A platform for sharing and discovering open data, including data from government agencies, non-profits, and businesses.
OpenDataSoft: A cloud-based platform for publishing, sharing and discovering open data, including data from national and local governments, research institutions, and businesses
OpenGeoHub: A non-profit organization that provides open data, open-source software and cloud-based services to enable collaborative work on geospatial data
ESRI ArcGIS Open Data: A collection of open data from around the world, including data from government agencies, non-profits, and businesses, that can be viewed, downloaded and analyzed using ArcGIS software.
GeoJSON: A lightweight format for storing and sharing geographic data, which is widely used and supported by many GIS software and web mapping libraries.
GIS Cloud: A web-based GIS platform that allows users to create, edit, and share maps and data.
World Geodetic System (WGS84): A widely used standard for geographic coordinates, used by GPS systems and many GIS software.
NASA’s Earthdata: A collection of satellite imagery, aerial photography, and other types of data, provided by NASA and other organizations.
GADM: A database of the location of the world’s administrative areas (boundaries of countries, provinces, and districts)
OpenTopography: A portal providing access to high-resolution lidar data and derived products for the research and education communities.
GeoIQ: A platform for creating and sharing interactive maps and data, with a focus on enterprise users.
GeoServer: An open-source server software for sharing geospatial data, which supports a wide variety of data formats and protocols.
GeoNetwork: An open-source platform for managing and sharing spatial data, which is widely used by government agencies and other organizations.
GeoNode: A web-based platform for creating and sharing spatial data, which is designed to be easy to use and customizable.
GeoDa: A free and open-source data exploration and visualization tool for geospatial data, which is widely used by researchers and students.
GeoPy: A python library that helps you find the geolocation of addresses, postal codes, cities, and other places using third-party geocoding services.
PostGIS: An open-source spatial database extender for PostgreSQL, which allows users to store and query geospatial data in a PostgreSQL database.
Major Terminologies Used in GIS
Here is a list of some common terms used in Geographic Information Systems (GIS):
Attribute data: Additional information associated with a geographic feature, such as population density or land use.
Coordinate system: A system of numbers, letters, or symbols used to identify the location of a point on the Earth’s surface.
Digitizing: The process of converting maps or other forms of spatial data into digital form for use in GIS.
Geodatabase: A database that stores and manages geographic data, including both vector and raster data.
Georeferencing: The process of aligning a map or image with the Earth’s surface using coordinates.
Metadata: Data that describes other data, including information such as the date of creation, the source of the data, and the data’s accuracy.
Overlay: A technique used to combine two or more layers of data, such as a satellite image and a street map, to create a new map.
Projection: A mathematical representation of the Earth’s surface, used to display geographic data on a flat map.
Raster: A grid of cells, each containing a value, used to represent data such as satellite imagery and digital elevation models.
Vector: A representation of geographic features as points, lines, or polygons, used to represent data such as roads, buildings, and political boundaries.
Spatial Analysis: A method for analyzing and understanding data with a geographic component.
Remote sensing: The process of capturing information about the Earth’s surface from a distance, typically using aircraft or satellites.
Web GIS: GIS that can be accessed and used through a web browser.
GIS software: A specialized software program used to create, edit, and analyze geographic data. Examples include ArcGIS, QGIS, and GRASS GIS.
Topology: The spatial relationships between geographic features, such as the adjacency or connectivity of polygons or lines.
Spatial join: A process in which the attributes of one layer are joined to another layer based on their spatial relationship.
Raster calculator: A tool used to perform mathematical operations on raster data, such as adding, subtracting, or multiplying raster layers.
Geoprocessing: A set of tools and techniques used to manipulate and analyze geographic data, such as buffering, clipping, and reclassifying.
Geostatistics: A branch of statistics used to analyze and understand spatial patterns in data.
GPS: Global Positioning System, a network of satellites and receivers that can be used to determine the precise location of a point on the Earth’s surface.
LiDAR: Light Detection and Ranging, a remote sensing technology that uses lasers to measure the distance to a target.
CAD: Computer-Aided Design, a technology used to create and edit drawings and maps in a digital format.
Web mapping: The process of creating and publishing interactive maps on the internet.
Location-based services: Services that use a device’s location to provide information or perform actions, such as providing directions or finding nearby businesses.
3D modeling: The process of creating a virtual representation of the Earth’s surface in three dimensions.
SDI: Spatial Data Infrastructure, a framework for sharing and managing geographic data across different organizations and systems.