GIS stands for geographic information system. GIS integrates hardware, software, and data for capturing, managing, analyzing, and displaying all forms of spatial information. GIS data can serve as a complete recor of the world's built and natural infrastructure.

• GIS is a tool for capturing, storing, checking, and displaying data related to positions on Earth’s surface.
• GIS can use any information that includes location. The location can be expressed in many different ways, such as latitude and longitude, address, place name, or ZIP code.
• Location is often the most meaningful information included in data.  GIS gives you the ability to show the meaning of data by showing how it relates spatially.
• GIS is a platform for organizing information in meaningful ways. It produces charts and graphs as well as maps.
• By showing the geographic relationships among seemingly unrelated data, GIS can help individuals and organizations better understand spatial patterns and relationships.

GIS provides visualization of data, which makes it easier to communicate complex ideas using large data sets. GIS visualization allows people to see connections between things that were hidden before. With better understanding of the data, people can make better decisions about how to deploy resources effectively.

With GIS technology, people can compare the locations of different things in order to discover how they relate to each other. For example, using GIS, a single map could include sites that produce pollution, such as factories, and sites that are sensitive to pollution, such as wetlands and rivers. Such a map can help people determine where water supplies are most at risk.

GIS saves money. For many organizations, especially government agencies, GIS makes it faster to gather and organize information, and much faster to create new maps as conditions change, corrections need to be made, or new questions arise. This increased speed allows agencies to respond much more efficiently.

GIS:

• Provides customized data sets (map layers) to fit needs
• Creates data that is easily shared.
• Allows organizations to respond more quickly to requests for information.
• Improves planning.
• Empowers people to understand information.
• Provides data and analyses in an easily understandable format.

GIS works by tying information about an object to its location on the earth's surface.  The information about objects in a GIS database may be queried to find where similar things exist or whether things with certain properties are close to each other.

Many data sources exist online. Federal, state, local, and commercial agencies gather information and much of it is available for public use. For instance, the Montana State Library and the Montana Department of Revenue maintain the cadastral map (https://gis.mt.gov/) that shows legal information for every parcel of land in the state.

GIS software (such as ESRI or ArcGIS) takes the data and builds map layers as needed. For instance, many land use maps might have some or all of these layers:

• Aerial photographs
• Topographic landforms
• Property boundaries (cadastral)
• Public and private land ownership
• Geology
• Soils
• Floodplain
• Hydrology
• Wetlands
• Conservation easements
• Roads and trails
• Zoning

Many different types of information can be compared and contrasted using GIS. Data isn’t just points on a map. Each data point can carry more information, such as the date and volume of a water right. The system can include data about:

• People, such as population, age income, or education level
• Disease incidence
• Animal and bird habitat and ranges
• The landscape, including land use, geology, soil type, and vegetation type
• Water, including rivers, streams, floodplains, wetlands, and water rights
• Locations of factories, farms, hospitals, and schools
• Locations of stores and restaurants, including hours of operation
• Boundaries such as property lines, zoning districts, school and fire districts
• Roads and electric power lines
• Storm drains, fire hydrants and fill ponds
• Recreational opportunities 

People use GIS without even realizing it. GIS is behind the scenes in many every day tasks:

• Choosing routes to drive or walk
• Finding the nearest coffee shop or gas station
• Pizza and package deliveries
• Pokemon GO
• Helping First Responders find the location of an emergency
• Fitness trackers
• Hunting maps
• Field guides
• One-call utility locators
• Obtaining property tax assessment information

Its's not.  Google Maps is a GIS application designed to let users easily do many things such as finding routes, finding addresses, and finding businesses.  The objects you see on Google Maps are connected to a powerful database with information such as speed limits, hours of operation, contact information, and customer reviews.  Google Maps has a limited set of GIS tools that you can use.  GIS professionals have a much larger tool set that allows them to develop apps for specific purposes such as predicting behaviour of wildfires or floods, analyzing electrical networks or traffic flow, and recording the condition of objects in the field such as pavement or power poles.

• The State Library maintains the Montana Cadastral viewer for Montana's land records.

• The State Library is the official host of the Montana Spatial Data Infrastructure (MSDI). MSDI is the collection of fifteen “framework” geographic databases vital for making maps of Montana and understanding its geography.

• The State Library is the home of the Montana Geospatial Information Advisory Council (MGIAC), a group that administers state grants of funds to groups around the state for maintenance of the MSDI databases.

• State Library staff directly maintain several of the MSDI databases.

• The State Library GeoInfo web site provides GIS professionals access to the MSDI data and to geographic databases created by other state, federal, and local agencies that do not have their own mechanisms for distributing their data.

• The State Library provides viewers, such as the Montana Digital Atlas and the Montana Map Gallery, for its geographic databases.

Some of the geographic databases available from the State Library include administrative boundaries, digital elevation models, lakes and streams, wetlands, drainage basins, land cover, soils, roads, structures and their addresses, aerial photographs, topographic maps, water rights, and groundwater wells.

The State Library makes GIS data available, free, to the public that is difficult to obtain in many other states. This makes many applications cheaper, easier, or possible. Agencies responsible for public safety easily access the information they need. Montana businesses use information from the Library to create innovative products such as a clearinghouse for rural properties and apps for hunters, thus generating new business and contributing to the state economy.

Most industries use GIS in one way or another, or will soon; it is difficult to name one that doesn’t use it in some way. GIS is heavily used for:

• Census planning
• Civil engineering
• Delivery services: mapping routes
• Ecology
• Emergency services
• Firefighting
• Google Maps
• Land use planning
• National and state parks
• Outdoor recreation
• Real estate
• Road construction and maintenance
• Surveying
• Tax assessments
• Taxis, Uber
• Trails
• Utilities
• Water management
• Wildlife management

Other uses include:

• Agriculture
• Anthropology
• Astronomy: mapping Saturn’s moon
• Biology: mapping the body
• Business: eg choosing a location for a new store
• Criminal justice
• Economics
• Forest economics: forecasting firefighting expenses
• Geology
• Geotechnical engineering
• History
• Law
• Literary Analysis: mapping stories such as On the Road
• Public health

• Where is it?
• Who owns the land?
• What is the fastest way to get there? The shortest?
• Where are the obstacles?
• What else is at that location?
• Who lives within two miles of the pipeline break?
• How many people are affected?
• How many people are within 30 minutes of diabetes prevention services?
• Where is the closest water source and what kind is it?
• Who owns the water rights?
• What is the vegetation? Soil type? Land use?
• What assets/buildings are there?
• What school district is it in? What fire district? What precinct?
• Where are the historic sites?
• What kind of road is it? What is its condition?
• How many miles of paved road are there in the County?
• Where should we put a command post/new fire station/fast food joint?
• What noxious weeds are present in my county?
• Where are the trees? What kind are they?
• Where is there high fire danger?
• What needs maintenance this year?
• Where are there hazards? Things that shouldn’t be disturbed?
• Who will be affected by a landslide at this spot?
• Which bridges are safe for heavy equipment to cross?
• Where are the trees in this town and what kind are they?
• Is there a pattern to where people are driving off the road?
• How healthy is my county?
• What are people in this neighborhood buying in this category?

• Geospatial technology
• Land Information System
• Spatial data infrastructure
• Spatial analysis
• Geographic Information
• Location intelligence
• Computer cartography

• National Geographic
• What is GIS?, explanation from a leading GIS software provider
• Geography Realm, a GIS learning site
• University of Wisconsin
• Wikipedia

• Montana Cadastral, the state land parcel database
• Montana Hunt Planner
• Montana Fishing Guide
• Missoula County Parks and Trails
• Montana Road Report