If you’re on the bleeding edge and have upgraded to ArcGIS 10.1, ESRI has added functionality to the Image Analysis tool to measure lengths / heights, areas, and volumes from imagery. Use of the new tool is outlined in this blog post.
A manual for learning to use ArcGIS 10, produced by Amy Hillier at the University of Pennsylvania, is available here. This 80+-page document covers many of the options new users should be familiar with, and includes tips on making maps, georeferencing, spatial joins, creating spatial data, and troubleshooting.
ESRI has created a nine page ArcGIS Desktop Tips and Shortcuts document. It lists keyboard and mouse shortcuts for many common operations, and identifies which work for versions 9 and 10 of ArcGIS (ArcMap and ArcCatalog). A shorter list is available in the ArcGIS 10 application help files. Tap F1 when ArcMap is running and search for keyboard shortcuts.
You can also use the Help files for ArcGIS 10 in the ArcGIS Resource Center. Search for keyboard shortcuts. Help for other versions of ArcMap (or other ESRI applications) can be found by going to the ArcGIS Resource Center and clicking Help. Expand the list for the application you are interested in (click the +) for help files from the older versions.
Tip: the help files from the Resource Center are the most up-to-date for all ESRI software. Sometimes updated documentation is not included with service packs and patches, but these files are kept current.
A history of the US-Canada border (which brings to light some realities of surveying in the 1800s) was recently posted on the NYT blog, found here. For more historical border issues (errors later pointed out using newer technology – GPS), see the Deseret news and the NOAA response.
The NOAA rebuttal is an interesting argument: even though a specific monument (the Four Corners marker that sits between Utah, Colorado, Arizona, and New Mexico) is at a location other than its intended coordinates, it doesn’t invalidate the boundaries between these states, nor does the meandering of the US-Canada border along the 49th parallel call into question the location of the border with our northern neighbors. The (connected) monuments, placed between 1872 and 1874, define the boundary, even if they do ‘wander’ across the parallel.
Given the tools surveyors had to work with in the 19th century, and the terrain they were crossing, the border between Minnesota and Washington is amazingly straight. It’s the development of newer tools (GPS and Google Earth, among others) that lets us discover such errors with relative ease.
On a final note, the Four Corners is a unique place in the U.S. It was even parodied in an episode of The Simpsons.
see http://www.guardian.co.uk/news/datablog/interactive/2011/nov/22/us-road-accident-casualties? for a map of eight years of traffic deaths, broken out by class, age, and year of fatality.
The Earth’s population reached seven billion this week. Nearly 1/3 of the total live in China and India.
How do different nations compare in terms of population, life expectancy, and growth? See http://mapstories.esri.com/7billion/ for some interactive maps showing these metrics.