Tag Archives: maps
By Stephen K. Bryce, Esri Federal Government Expert
Since August 25, 1916, when President Woodrow Wilson signed the act creating the National Park Service, and continuing on through June 24, 2016, when the NPS added its 412th site, Stonewall National Monument, maps have communicated the importance of the nation’s most valued treasures. For a century NPS has created maps for survey, preservation, conservation, planning, tourism, search and rescue, facilities management, and more. Beginning its second century of custodial care, the NPS is modernizing web flows by bringing web GIS services into the mainstream of its map production.
The electromagnetic spectrum
In the early history of powered aircraft, aerial photographs—pictures of the earth from above—began to be found useful for military and scientific applications. Quite quickly, imaging professionals and scientists realized that it was possible to detect beyond what is visible to the unassisted human eye. Deeper and richer information could be revealed by detecting waveforms from beyond the rainbow of visible light, into the invisible. As it turns out, these hard-to-detect realms of the spectrum offered some of the most meaningful insights. Hidden in these signals were previously unknown facts about Earth that have enabled us to understand our world far more effectively than had been possible.
Multispectral imagery: Enabling extrasensory perception
One of the most extraordinary types of imagery collected by remote sensing is multispectral imagery. Each image is composed of data from a series of onboard sensors that collect small slices (or bands) across the electromagnetic spectrum. The table below shows the complete list of wavelengths (expressed as bands) that are collected by the Landsat 8 imagery according to what they capture. The images below are examples of what you “see” by combining different bands into red, green, and blue electronic displays or hard-copy prints.
The Natural Color (bands 4, 3, 2) combination of red, green, and blue is well suited for broad-based analysis of both terrestrial and underwater features and for urban studies.
Color infrared photography, often called false color photography because it renders the scene in colors other than those normally seen by the human eye, is widely used for interpretation of natural resources.
Land and water interface
Landsat GLS Land and Water Boundary (bands 4, 5, 3) emphasizes the edges between land and water.
This 6, 5, 4 band combination shows irrigated vegetation as bright green. Soils appear as tan, brown, and mauve.
Multispectral band combinations
Multispectral imagery measures different ranges of frequencies across the electromagnetic spectrum. One way to think of these different frequencies is as colors, where some colors are not directly visible to human eyes. These frequency ranges are called bands. Different image sensors measure different band combinations. The longest-running and perhaps most well-known multispectral imaging program has been Landsat, which began Earth image collection in the 1970s. By assigning data from three bands of the sensor to the red, green, and blue channels of an electronic display (or printer for a hard copy), color visualizations are created. Here are some examples of various alternate band combinations and their applications.
Panchromatic imagery, commonly known as pan, is typically recorded at a higher resolution than the multispectral bands on any given satellite. It remains a critical source for many GIS applications as a reference for basic interpretation and analysis. Pan is often combined with other bands through a process called pansharpening to generate higher-resolution scenes.
In the Agricultural band (combination 5, 4, 1) vigorous vegetation appears bright green, healthy vegetation appears as a darker green, and stressed vegetation appears dull green.
The Normalized Difference Moisture Index (NDMI) estimates moisture levels in vegetation where wetlands and vegetation with high moisture appear as blue growing to dark blue for higher moisture levels, and drier areas appear as yellow to brown shades. Image analysts often apply a formula to combine the selected multispectral bands to calculate various indexes.
This post is excerpted from The ArcGIS Imagery Book: New View, New Vision. Imagery is suddenly a big deal, and those who are adept at finding it, analyzing it, and understanding what it actually means are going to be in demand in the years ahead. The purpose of this book is to help everyone from GIS professionals to app developers, and web designers to virtually anyone how to become smarter, more skillful, and more powerful appliers of image data. The book is available through Amazon.com and other booksellers, and is also available at http://www.TheArcGISImageryBook.com for free.
Story Maps let you combine interactive maps and scenes with rich multimedia content to weave stories that get noticed. Here are some things you should consider when creating story maps.
Think about your purpose and audience
Your first step is to think about what you want to communicate with your story map and what your purpose or goal is in telling the story. Who is your audience? Are you aiming your story at the public at large, or a more focused audience, like stakeholders, supporters, or specialists who would be willing to explore and learn about something in more depth?
Spark your imagination
Go to the Story Maps Gallery to see some examples handpicked by the Esri Story Maps team to inspire you and highlight creative approaches. You can filter and search the gallery to check out how authors have handled subjects and information that may well be similar to yours. Explore. Get a gut feel for what makes a good story.
Safe Communities Meet Up Features Senior Advisor to the White House, Program Lead from Department of Homeland Security
Law enforcement across the country are working to fulfill the President’s Police Data Initiative (PDI) to improve public trust and police legitimacy. GIS is an invaluable tool to help communities use open data to protect lives, property, and critical infrastructure. Esri has committed a vast amount of software and resources to help police departments across the nation access and understand information in order to keep communities safer.
The U.S. Department of Homeland Security’s Homeland Infrastructure Foundation Level Data (HIFLD) provides national foundation-level geospatial data that can be used to support community preparedness, resiliency, research, and more. Esri’s ArcGIS platform is the system that provides access to this information.
Esri Joins Americas Conference on Information Systems as Keynote Sponsor Discussing “The Age of the Location Platform”
By Christopher Cappelli
The annual Americas Conference on Information Systems (AMCIS) is one of the leading conferences presenting research by and for academics in the Information Systems and Technology field. The conference is organized by the Association for Information Systems (AIS), the premier professional association for individuals and organizations who lead the research, teaching, practice, and study of information systems worldwide.
At this year’s AMCIS, Esri will participate for the first time as keynote speaker and sponsor, representing its GIS software. As the world’s leading provider of GIS technology worldwide, Esri is happy to join AIS in educating and inspiring the next generation of IS and IT professionals.
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.
To remain healthy, vibrant, safe, and resilient, America’s counties must anticipate and adapt to all types of challenges and changes. This is the canon of the National Association of Counties (NACo), an organization that unites more than 3,000 American county governments. Many of these counties are moving their IT out of an age of legacy stovepipe systems into the digital age of enterprise IT systems.
Jack Dangermond, whose company Esri leads the world in GIS technology, was a featured speaker at the NACo eighty-first annual conference and exposition in July 2016. He shared his vision about the future of smart communities in which government is more responsive, productive, efficient, transparent, and engaged with its citizens. The overarching theme of the Esri president’s presentation was that GIS enables a smarter world.
Among the company’s lofty goals is its initiative to create a greener infrastructure for America. Esri has created a planning and development solution for analyzing ways to accommodate community growth without adversely impacting the environment. Counties can see what’s at stake—inside and outside their borders—and take action to preserve valuable cultural, scenic, ecological, and agricultural landscapes.
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.
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.
Collections of images
The recommended data structure within ArcGIS to manage and process imagery is the mosaic dataset. A mosaic structure enables significant big data capabilities for large, even massive, image collections. Each mosaic is composed of a number of related raster datasets, enabling you to keep your original individual image files on disk and to access them as part of a larger, integrated single collection. Mosaics are used to create a continuous image surface across large areas. For example, among other scenarios, you can use mosaics to handle coverage of very high-resolution image files for an entire continent. Or you can manage an entire historical map series for a nation for every year and every map scale. You can even manage huge multidimensional collections of time series information for earth observations and climate forecast modeling (often referred to as 4D). Creating mosaics is straightforward. You can point to a series of source georeferenced image files and automatically assemble a mosaic in minutes where each image acts as a tile within the collection.
Managing extremely large collections