Tag Archives: ArcGIS Book

GIS is Collaborative

Your own GIS is simply your view into the larger system. It’s a two-way street. You consume information that you need from others, and in turn, you feed your information back into the larger ecosystem.

Geography is key for integrating work across communities

Modern GIS is about participation, sharing, and collaboration. As a Web GIS user, you require helpful, ready-to-use information that can be put to work quickly and easily. The GIS user community fulfills that need—that’s the big idea. GIS was actually about open data long before the term gained fashion because the people who were doing it were always looking for ways to deepen and broaden their own GIS data holdings. No one agency, team, or individual user could possibly hope to compile all the themes and geographic extents of data required, so people networked about this to get what they needed.

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Important 3D Terminology

Getting the z-terminology straight

Maps and Scenes

GIS content can be displayed in 2D or 3D views, and there are a lot of similarities between the two modes. For example, both contain GIS layers, both have spatial references, and both support GIS operations such as selection, analysis, and editing.

However, there are also many differences. At the layer level, telephone poles might be shown in 2D as brown circles, while the same content in 3D could be shown as volumetric models—complete with cross members and even wires—that have been sized and rotated into place. At the scene level, there are properties that wouldn’t make sense in 2D, such as the need for a ground surface mesh, the existence of an illumination source, and atmospheric effects such as fog.

This scene shows the global pattern of airports and the interconnected air traffic routes using the openflights.org data.

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Mapping the Third Dimension

A Change in Perspective

3D is how we see the world. With 3D Web GIS, you bring an extra dimension into the picture. See your data in its true perspective in remarkable photorealistic detail, or use 3D symbols to communicate quantitative data in imaginative ways, creating better understanding and bringing visual insight to tricky problems.

The Evolution of 3D Mapping

Throughout history, geographic information has been authored and presented in the form of two-dimensional maps on the best available flat surface of the era—scrawled in the dirt, on animal skins and cave walls, hand-drawn on parchment, then onto mechanically printed paper, and finally onto computer screens in all their current shapes and sizes. Regardless of the delivery system, the result has been a consistently flat representation of the world. These 2D maps were (and still are) quite useful for many purposes, such as finding your way in an unfamiliar city or determining legal boundaries, but they’re restricted by their top-down view of the world.

Some stories lend themselves very well to 3D storytelling. The Mountains of Fire story map is composed of a number of 3D web scenes.

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Modeling: What can patterns tell you?

Some problems demand you go beyond exploring the data into quantifying relationships or formally testing hypotheses. This is where modeling comes in. Spatial modeling allows you to derive new data from values of existing data layers and to predict what might happen and where. Modeling often takes you into the realm of developing specialized workflows through programming. Creating scripts and automated workflows lets you efficiently query and process large amounts of data and implement more complex algorithms. Increasingly, the value of sharing methods and code through the web allows you to create complex workflows without the need to develop all the components. Knowledge is being shared by putting the real power of spatial analysis into the hands of more people.

Modeling Processes

With an understanding of the processes at work in the natural or human environment, additional features can be modelled from spatial data. Using an elevation surface, for example, you can derive information and identify features that were not readily apparent in the original surface, such as contours, angle of slope, steepest downslope direction (aspect), shaded relief (hillshade), and visible areas (viewsheds). You can model the flow of water across Earth’s surface, deriving runoff characteristics, understanding drainage systems, and creating watersheds.

This GIS app shows how GIS was used to model areas that cougars would be likely to traverse through the mountains and wildlands near Los Angeles. Wildlife conservation experts stress the need to identify safe corridors, including natural bridges, so the big cats in isolated populations can find each other.

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Smart Mapping Workflows

Your world is full of data, and maps help you to make sense of it. There is a growing need to turn geographic data into compelling maps. All users want to create beautiful, interactive maps and infographics with live data, easily and with confidence. The smart mapping mission is to provide a new kind of strong “cartographic artificial intelligence” that enables virtually anyone to visually analyze, create, and share professional quality maps in just a few minutes, with minimal mapping knowledge or software skills.

Smart mapping is designed to give ArcGIS users the confidence and ability to quickly make maps that are visually pleasing and effective. Cartographic expertise is “baked” into ArcGIS, meaning it is part of the fundamental user experience of using ArcGIS. The map results that you see in front of you are driven by the nature of the data itself, the kind of map you want to create, and the kind of story you want to tell.

The best thematic maps apply thoughtful analysis of the underlying data to a set of map parameters designed to bring focus and clarity to the topic. Here, the author has positioned the handles controlling symbol size (running beside the histogram) to emphasize areas with household incomes over $100,000. Great maps relate the data back to the real world, using visual cues that immediately highlight the message you want to convey.

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The Importance of Where

How Spatial Analysis Leads to Insight

Spatial analysis allows you to solve complex problems and better understand where and what is occurring in your world. It goes beyond mapping alone to let you study the characteristics of places and the relationships between them. If the spatial component is important to the problem, spatial analysis lends perspective to your decision-making.

Spatial Problem Solving

Have you ever looked at a map of crime in your city and tried to figure out what areas have high crime rates? Have you explored other types of information, like school locations, parks, and demographics to try to determine the best location to buy a new home? Whenever we look at a map, we inherently start turning that map into information by analyzing its contents—finding patterns, assessing trends, or making decisions. This process is called “spatial analysis,” and it’s what our eyes and minds do naturally whenever we look at a map.

Spatial analysis is the most intriguing and remarkable aspect of GIS. Using spatial analysis, you can combine information from many independent sources and derive new sets of information (results) by applying a sophisticated set of spatial operators. This comprehensive collection of spatial analysis tools extends your reach toward answers to your questions. Statistical analysis can determine if the patterns that you see are significant. You can analyze various layers to calculate the suitability of a place for a particular activity. By employing image analysis, you can detect change over time. These tools and many others, which are part of ArcGIS, enable you to address critically important questions and decisions that are beyond the scope of simple visual analysis. Here are some of the foundational spatial analyses and the ArcGIS tools that get them done.

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The Online Mapping Revolution

Maps are important. Everyone understands and appreciates good maps. GIS people work with maps every day. Maps provide the basic experience and practical interface for the application of GIS. Maps are also the primary way that GIS users deliver their work.

Maps provide a critical context because they are both analytical and artistic. Maps carry a universal appeal and offer clarity and shape to the world. They enable you to discover and interpret patterns and share your data.

Online maps can be created by virtually anyone using Web GIS—and can be shared with virtually everyone. These maps bring GIS to life and can go with all of us everywhere on our smartphones and tablets.

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The Power of Apps

Focused Tools that Solve Problems

With billions of users worldwide, apps are a technology trend that has captured the world’s attention. Online maps provide the information that powers the use of GIS. And every map has an interface—a user experience for putting that map to use. These experiences are apps, and they bring GIS to life for users.

The Rise of Spatially Intelligent Apps

Apps are lightweight computer programs designed to run on the web and on smartphones, tablets, and other mobile devices. GIS apps are a special breed; they’re map-centric and spatially aware. Seemingly overnight, apps are ubiquitous. Billions of people worldwide run them in their web browsers, on computers and, of course, on their mobile devices. Creating interesting geographically aware apps is now within your reach. From the intuitive Story Map app and Web AppBuilder to the app collection for your smartphone and tablet, the technology required to deploy highly effective apps that can really engage an audience is accessible.

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Visualization: What can my map show me?

In many cases, just by making a map you are doing analysis. That’s because you’re making the map for a reason. You have a question you want the map to help answer: Where has disease ravaged trees? Which communities are in the path of a wildfire? Where are areas of high crime? It’s also because when you make a map, as with any analysis, you’re making decisions about which information to include and how to present that information. Effective visualization is valuable for communicating results and messages clearly in an engaging way. Here are three key decisions that affect the information a map presents and the story it tells.

Choose Scale

The scale of the map itself (the area you’re showing) and the scale of the data you use both affect what your map will show. A classic example of how your choice determines the question answered is whether to show presidential election results by state or by county. While the state-level data does show a distinct national pattern, the county-level map reveals much more nuanced local and regional patterns. Map A answers the question, What is the pattern of states (and electoral votes) won by each candidate? Map B, about voting by county, better answers the question, What is the distribution of Republican and Democratic voters in this election?

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The Role of Web Maps

Web maps are online maps created with ArcGIS that provide a way to work and interact with geographic content organized as layers. They are shared on the web and across smartphones and tablets. Each web map contains a reference basemap along with a set of additional data layers, plus tools that work on these layers. The tools can do simple things like open a pop-up window when you click on the map, or more complex things, like perform a spatial analysis and tell you the relative proximity of healthy food options by neighborhood.

At their heart, web maps are simple. Start with a basemap and mash it up with your own data layers. Then add additional tools that support what you want your users to do with your web map: tell stories; perform analytical studies; collect data in the field; or monitor and manage your operations.

Virtually anything you do with GIS can be shared using web maps. And they can go anywhere. Web maps work online and on any smartphone, and along with your supporting GIS work, are accessible anytime.

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