Field Testing Maps for Hiking

This weekend we tried out hiking maps for use with our cell phones.  We created the maps with digital data downloaded from the web, and then downloaded them to the phones to use with my software.

For field verifitcation, we went to Susquehanna State Park, where we took the Lower Susquehanna Heritage Greenway Trail, to the base of the Conowingo Dam.  Coming back we took trails above the river level, labelled as very strenuous, what that is a very East Coast flatlands view of activity levels.  Altogether we hiked about 14 km.

At the dam.  Our visit was inspired by a show on MPT about the dam.

It might have been peak flower season in the flats along the river.

This was not prime time for eagles, (and the attendant bird watchers),  but we saw ducks, herons, and a few eagles.

Our route on a merge of the 4 USGS topo quads that covered it.

Our route on the DSM created with the lidar point could.  Most of our route was in the trees, for which this map is not very helpful

Our route on the MD DNR state park map.  This was the first park map I have seen that was a GeoPDF, with the potential for using the map in a GIS program or a mapping program on the cell phone.

Close up of the USGS map.  This one has the trails on it; when we hiked in Joshua Tree National Park, and at Sedona AZ, last month, the USGS maps did not have hiking trails, so we had to add them from OpenStreetMap.

Directions for data download, processing on the PC, and transfer to the phone are at https://www.usna.edu/Users/oceano/pguth/hiking_maps.html   If you have questions, use the forum at http://forums.delphiforums.com/microdem/start.  We are working to make the process as seamless as possible, and document it.

Map Names and Politics

When I was teaching last fall, I adapted many of my sample data sets and examples to the local country.  There was not the same quantity of high resolution map data (the US is just about unique in the quantity and quality of free mapping data, but that is rapidly changing for western Europe, which is many cases now has better lidar data).

When we talked about the national projection, my students told me the country had 4 zones, I, II, III, and IV.  When I checked with the international repository of map projections, http://www.epsg-registry.org/. I could only find zones I and II.  After some digging, III and IV had different names, but the same parameters.  III and IV covered one of the cartography "in limbo" places like Gaza, the West Bank, or Kashmir, or the names of the seas between Korea and Japan or Iran and the Arabian Peninsula.  Or to come closer to home, the different status of US mapping data covering the "other" areas like the USVI, Puerto Rico, Guam, American Samoa, which have become much more normalized and treated like the states and DC since I started doing GIS.   But the normalization may not be perfect; the Census Bureau apparently could not come up with a citizenship question for the 2020 Census that covered all the categories of citizenship for residents of those places.

I was reminded of the power of names today, when I noticed on a science paper that the publisher did not consider any maps in the paper to have authoritative boundaries or place names, which has been a long time tradition with the US State Department and other US mapping agencies.  You have to be careful what you put on the map, and necessarily accept the version from one side of the border.  You can see the same thing in Google Earth or Google Maps, if you look at any of "in limbo" places.

Legal disclaimer from NGA for the gazetteer files.

Legal disclaimer from large commercial publisher of scientific journals.

Maps of Dreamland

This map shows the coverage of the US with the  USGSTopo maps available online in PDF format.  The colors show the year the maps were created.  What is more interesting is that there is one void in the lower 48 states, the white patch in southern Nevada.  

Zoom in to show the region without current USGS topo maps.  Note the red urban area in the SE part of the map, which is part of Clark County, or urban Las Vegas.   Nothing crazy going on there, beyond the normal for Las Vegas.  To the north is heaven (one of the quads in actually named Heaven's Well), some of which is really hard administratively to get into--I've tried, and have been in parts of it.  Some of it also very open federal land belonging to the Desert National  Wildlife Range, protected only by few roads and rugged topography.  The easternmost row of missing quads includes the Sheep Range, where I mapped for my PhD, and have led a series of field trips to see the spectacular geology.   I had previously discovered that this much of this area lacks the high resolution imagery which covers most of the rest of the US.  

All good things come to an end

We have left Rabat, and are now back in the US.

The focus of the blog will now  shift more to computer mapping.........