Visa trip

Visas are one of the less pleasant parts of travel.  We're spoiled, because we rarely need one to travel overseas, with some exceptions which for us have to the trips to Thailand and China.  I've also needed one to a certain western European country, but only because I had to travel on an official passport, and the employer handled most of the bother after I got the photo and filled in the paperwork.  But those issues pale in comparison with what many foreigners have to go through to visit the US.

Here in Morocco, you get the visa when you arrive, it's free, and the only catch is that it's only good for 90 days.  Then you "have" to go out of the country.  While there is a theoretical way to get a longer document, we were advised not to bother, and to accept the hardship of  a weekend in Europe.  We picked Madrid, due to cheap flights with RyanAir, which turned out to be very pleasant.

In Madrid, we visited a lot of museums: the Prado (art), the Archaeological Museum (professional stop; in the section on exploring in the 1400's and 1500's there was an astrolabe engraved with a stereographic net, used in both geology and mapping), the National Library (BNE, another professional stop, as their sign promised an exhibit on maps, which are both beautiful and related to my GIS teaching), and the Naval Museum (another professional stop, to go with the naval museums in Sweden, England, France, and the Netherlands where I have taken students).

To get around, we did a lot of walking, to walk off the calories from all the tapas.  It was a chance to test my mapping software, using the Spanish lidar data on the web.  After using it, I think it is close to the best from the 8 countries I have been using.  It was a very complete classification, and is the only country to include RGB imagery in the lidar files.  It is one of the lower resolution data sets, only able to produce 2 m grids, but that is adequate, and keeps the file sizes down.

The maps below show our routes, over the three days.  The GPS did not record for some short stretches, and you can see places where the urban canyons led to incorrect positions, and meandering roads even when we walked in straight lines.

The lidar classification, overlaid on a DSM to provide some shadows.

Elevations on the DSM.

Lidar return intensity, probably from a near infrared (NIR) laser.

The RGB, from a mapping camera flown with the lidar.  Note that Madrid is full of red tile roofs.

This is the map I used the most on my phone, with our hotel marked with the blue symbol, and the subway stops also marked.  The weather was so nice, and the city compact, that we wound up only using the subway to and from the airport.