Hiking maps

Norway has a series of 1:50K topo maps which make outstanding displays on your cell phone for hiking.  They have directions which translate into English.  They suggest using GeoViewer from LizardTech, but you can also use Avdenza PDF Maps  or the Android version of MICRODEM.

These use the proprietary MrSID format, of which I am not a great fan since software must go through the LizardTech interface, and I prefer that government mapping data use free and open formats.  It has also been years since I have seen any data in this format, and had considered removing it from MICRODEM as just bloat in the program.

However the implementation in Norway turned out to be very good.

The format is multiresolution.  The best resolution is 2.5 m per pixel, although the 5 m resolution is virtually indistinguishable and takes up 1/4 of the disk space. 

There is a single file for each of the 18 Norwegian counties, which correspond with US states or provinces in most other countries.  They range in size from 11 to 500 MB for the 8 we downloaded, which took up a total of 1.5 GB (a relatively small download for a FIOS home connection). Uncompressed as a Geotiff they take up about 200 times more disk space, but you only want to look at them subset and zoomed in.

 

The data for Oslo.  This scale is only useful to pick the region to extract at full scale.

Downtown Oslo at full scale (2.5 or 5 m per pixel. which are visually very similar).  Note that there are symbols for navigation aids, and these maps could probably be used as nautical charts--we follower the progress of the ferries we took on them (NB, they probably have severe, legalistic warnings that you should not use them for this, just like your GPS warns you not to rely on it, even if at its worst it will be better an any your options for getting your position).

There is a version with hillshading, but it is very subtle, and might not we worth the doubling in size of the MrSid files.

Map of Svolvaer.  The hiking trails are show on the map, so you can use the GPS on the phone to follow your hike.

The maps are visually very appealing; I think European topo maps are generally much prettier than those in the USA.  The US topos now use PDF format, with the rationale that the KISS nature makes them good for the general public and they don't think real GIS users should want to use them.  It also means you must download a number of individual files and then figure out how to merge them, which GDAL now makes relatively simple if tedious.

The only real drawback to using these maps on your phone for navigation on your cellphone is the GPS draining of the battery; you need an external battery to get past the half day mark.

Arctic Circle

We just got back from a trip to Norway, and traveled north of the Arctic Circle.  Since it was almost the June solstice, we have 24 hours of daylight.  We used trains, automobiles, Hurtigren ferries, and an airplane.

Route of the ship in red, overlaid on the Norwegian topo map.  The ferry makes a big deal of crossing the Arctic Circle, and encourages everyone to come up on deck to see the monument on Vikingen Island.

Vikingen Island, with the monument on the right side.

Closeup of the monument.

The passengers on deck to get pictures, providing some idea of the conditions at 0715.

In my intro oceanography and physical geography classes, we teach that the Arctic Circel is as 66.5 degrees north.  The Norwegian maps show the monument at 66.53 degrees, but shows something else a few km to the north.  I did not stay on deck to investigate it at the time

The Arctic Circle in 2015, at 66.56 north.  If you want to be precise,  66.5 is not accurate enough, and you also have to account for the fact that the earth wobbles, and the Arctic Circle migrates about 15 m a year.  It would have been at Vikingen quite some time ago, so there may have been some licence with the placement of the monument to create a tourist trip moment for the cruise ships.

The Prime Meridian used to have a similar monument, and a lone of people lined up to get their picture with each leg in a different hemisphere.  There are issues with the exact location, and the Observatory has to explain why your GPS does not show 0 when you straddle the line.  The last time I was at Greenwich, the monument was gone, and with no need for a backdrop, the lines to get the picutre were gone.