The National Geodetic Survey (NGS) has been working for over a year now to adjust the NAD83 datum with what is called the National Adjustment of 2011 or NA2011. How much adjustment are we talking about here? If you guessed only about two centimeters, you would be right on the money.
So why are the NGS geodesists working so hard for such a small change and is it worth the potential problems it could cause users of NAD83? It turns out the reasoning behind the adjustments are sound and will be a benefit to the future of surveying and GPS usage.
The main advantage of the NA2011 is that it will tie together and align passive(in ground monuments) and active(CORS) control stations throughout the United States. There are roughly 80,000 passive control marks that will be effectively brought into the modern system.
It is important to remember that this is not a new datum (that will be coming in about ten years); It is an adjustment of the current NAD83 datum. However, there will be a new geoid model (Geoid12) as a result of the changes. Of course this new hybrid geoid will not be developed until after the NA2011.
Fun stuff! The projected completion date for the adjustment is June 30, 2012 so it could be just around the corner. Of course they had originally planned on completing it before the end of 2011 but maybe this time they will be on schedule. If you want more information about the NA2011 you can visit the NGS web site.
I finally got around to playing with National Geographic’s MapMaker Interactive application on the organization’s education site. As a GIS analyst with two young boys I am always interested in tools that can help teach them about geography or GIS. The MapMaker tool helps teach both of these.
The interface is built on the ArcGIS framework using the ArcGIS API for flex. It features eight base maps to choose from including National Geographic view, satellite view, streets view and oceans view. There are also six themes (with related sub-themes) such as water, land, climate and population, that help users turn out handsome looking maps quickly.
The drawing tools are very user-friendly and include only six basic tools. In addition to these, there is a “markers” tab that provides 30 different symbols representing vegetation, structures and events. You choose between three different marker sizes then drag and drop the marker where you want the point to be located.
Other than looking at the prefabricated themes or measuring distances between locations there is really no analysis that can be done with this map. However, the tool is called MapMaker, not MapAnalyzer, and is geared toward kids so one really cannot complain.
While kids might be the target audience of the MapMaker, its simplicity lends itself to be used by adults who are not GIS savvy but might want to make a quick and authoritative looking map for a manager or client.
The National Geographic education site is still in Beta at the time of this post so there are still a few issues with the tools acting buggy. It would also be great to see a PDF export option and a way to retain measurement annotation as a permanent part fo the map. Those are just minor complaints though and the functionality may well change as the web site goes through and comes out of Beta.
Overall this is a great tool to use for basic mapping or teaching about geography and geographic information systems. Head over to the site and give it a try. You might find that you have another free tool that you can use to make a quick one-off presentation map or you can recommend it to a non-GIS user who wants to play cartographer.