Ten teams of students measured the perimeter of a seven-sided traverse using pacing and taping. Each leg was measured twice. The standard deviations of the measurements of the perimeter showed that pacing gave much more variable results. Pacing also had a much wider certainty range at different probabilities.
                                           Pacing       Taping

Average	1056.1	1065.0
Standard Deviation	49.3	7.5
Maximum	1172	1071.61
Minimum	995	1051.1
Difference	177	20.51

Here is John Bardi's presentation from Penn State Mont Alto's Professional Development Day. Click on the bottom right to see the presentation full screen.

I never knew that map projections had personalities...

Image permalink.

Yesterday I attended the GIS Day at Harrisburg Area Community College's Downtown Center with the Aerial Photo Interpretation (FORT 230) class. This is a new event that has only been running for a few years. It already has some interesting displays and presentations and could grow bigger in the future. Here are impressions of some of the exhibits.

DCNR's Explore PA trails shows recreational trails around the state. Its interface uses an embedded Google Maps window. Trails can be searched through the interactive map or a parameter search. Users can register to add comments, photos, and possibly upload trail information. This is a great website that should attract many viewers.

The PA Historical and Museum Commission and PennDOT have created a very interesting Cultural Resources Geographic Information System. The web site shows historical sites and zones throughout Pennsylvania. Each historical site links to other resources, including historical photos. There is a general public user level and more detailed user levels for archaeologists and those with demonstrated need.

I was eager to try this tool at home. But when I tried to log on I found out that it only works with Microsoft Internet Explorer. Then I found out it requires the installation of Adobe SVG Viewer. This tool was discontinued in 2009. It is still available, but is no longer supported. The installation instructions didn't mention Windows Vista or 7! I am disappointed the tool hasn't been modernized. I imagine that it would be quite expensive and time consuming to switch to another map database and online system.

Another interesting display was the Appalachian Mountain Club's Pennsylvania Highlands Recreational Guide. They have mapped a network of trails either connected to the Appalachian Trail or in its corridor. They have an ongoing effort to update the network.

The PA Department of Health had a display on the Environmental Public Health Tracking Program. This effort, in partnership with many agencies including CDC, maps various diseases and health conditions around the state. The site provides links to data and maps. There is a public level and more detailed levels for health officials.

It will be interesting to attend this event next year.

Google Earth and Google Maps are ideal to help learn about issues in geography. On this map are a few points that we will use for discussion today.

 

View Google Earth Sites for Discussion in a larger map

Download the kml file to open these points in Google Earth.

Black and White (panchromatic)

View FORT 130 - Topographic Evaluation Field Trip in a larger map

View Woodlot Map in a larger map