Home
Technology Articles
Information Technology Articles
General Information Technology Articles

GIS For Dummies Cheat Sheet

By: 
Jami Dennis
|
Updated:  
2025-05-05 13:46:49
|
From The Book:  
GIS For Dummies
GIS For Dummies
GIS For Dummies, 2nd Edition book cover
Explore Book
IT Disaster Recovery Planning For Dummies
Explore Book
Buy On Amazon

A geographic information system (GIS) is a software for making maps, analyzing data, and more. This cheat sheet tells you about what you can do with GIS, provides a handy guide to raster-based functions, gives you some key ideas to keep in mind about maps (relating to scales, projections, and datums), and the X, Y, and Z of GIS.

What you can do with the GIS

To get the most out of GIS, you need the combined power of its five main parts:

  • Hardware: The devices that power GIS, from laptops to desktops to printers and everything in between.
  • Software: The apps that provide the tools and functionality to store, analyze, and display geospatial data.
  • Data: The essential ingredient, without it you have nothing to analyze or map!
  • Methods: The plans, processes, and workflows for turning raw data into meaningful insights.
  • People: GIS requires people to manage, develop, maintain, and apply it.

With GIS, you can perform all sorts of both fun and valuable geography-related tasks such as find the best place to locate your business, map the fastest route to your favorite pizza joint, or predict where wildfires may spread. But GIS can do so much more! Here’s a sampling of other ways GIS helps you make sense of the world around you:

  • Find places on a map. Search a GIS database to locate features by their name, their size, or their location in relation to other geographic features.
  • Measure distances and areas. GIS can measure lengths, widths, areas, and even volumes — handy when you need to know how long a road is or the size of a park.
  • Analyze patterns. See how geographic features are distributed. For instance, how spread out they are, how close they are to each other, and how they relate to other features.
  • Summarize data. Crunch numbers on geographic features, from simple stats (like averages and medians) to complex spatial statistics.
  • Work with networks. Find the best routes based on time, distance, or other factors. Plan bus routes, optimize delivery paths, or figure out where to open a store to reach the most people.
  • Compare map layers. Stack different layers (like roads, population, or land use) to see how they interact. Stacking layers helps you spot relationships and make better decisions.
  • Analyze surfaces. Work with elevation, temperature, and other surface data. Use interpolation and other tools to find missing values and uncover patterns.

Raster-based GIS map functions

If your GIS (geographic information system) works with raster data, you have access to some powerful, algebra-based functions. The following table shows the types of raster functions, where they apply, and what you can do with each:

Function Type Where It Works What It Does
Local On individual grid cells Changes cell values based on user input or values from other layers
Focal On a grid cell and its neighbors Calculates values (like an average) based on surrounding cells
Zonal On grid cells grouped into defined zones Analyzes and summarizes data for specific regions, even if they aren’t connected
Block On groups of adjacent grid cells (square blocks) Returns a single value for each block (for example, a 4-x-4 block of cells
Global On the entire grid Identifies large-scale patterns and highlights hard-to-find features
Specialty On specified grid cells Performs advanced statistical analysis or models moving surfaces (like water or pollution)

Key facts to understand about GIS maps

GIS (geographic information system) is a handy and powerful tool for mapping and analysis, but what you see on the screen doesn’t always match reality. Maps simplify, generalize, and often distort features to make them easier to work with. As you use GIS, keep these key facts in mind:

Map Characteristic What It Means
Maps are models, not miniatures. Maps simplify real-world features using symbols so that everything fits at the scale you’re working with. They’re not exact replicas.
Map scale has a huge impact on GIS analysis. Small-scale maps cover large areas with little detail, whereas large-scale maps cover small areas with lots of detail. Understanding scale helps you interpret maps and geospatial data correctly.
Maps flatten our spherical earth. Because Earth is a lumpy sphere, GIS uses projections to display it on a flat map. Every projection distorts shape, size (area), distance, or direction in some way; we have no way around that fact.
Maps have a reference grid, or coordinate system. The reference grid (such as latitude and longitude or UTM) helps you locate places accurately and links the map with the real world.
Maps have a reference starting point, or datum. A datum is a model of the Earth’s shape (what geodesists call a reference ellipsoid) that provides a baseline for accurate positioning and ensures that different projections align correctly.

Types of GIS output

GIS is about maps, but that’s just the beginning. GIS can generate a variety of other outputs that help you analyze, visualize, and present geographic data. Here are some of the main types:

  • Maps (of course): Everyone recognizes the most common GIS output.
  • Cartograms: These are special maps that resize or distort geographic features based on values rather than actual geography. (A subway map is a great example.)
  • Charts: GIS can produce pie charts, bar charts, line graphs, and even pictures in addition to maps.
  • Directions: GIS can provide step-by-step navigation for getting from point A to point B.
  • Customer lists: Business GIS applications often create customer mailing lists, reports, and targeted marketing tools.
  • 3D diagrams and animations: These elements bring GIS data to life, helping you to see the results of your work realistically and dramatically.

Bonus: measuring the earth

Because practically every GIS professional has a sticky note near their workstation with this reminder, here are the X, Y, and Z of GIS:

  • X = Longitude (East-West position)
  • Y = Latitude (North-South position)
  • Z = Altitude, elevation, depth, or other vertical measurements

‍

About This Article

This article is from the book: 

GIS For Dummies

About the book author:

Jami Dennis is a certified GIS Professional with more than 30 years’ experience in GIS, socio-economic research, demographic studies, data analysis, and data visualization. She is the owner of Geodetic Analysis, LLC.

This article can be found in the category: 

General Information Technology