TOPIC: SAN FRANCISCO
A way to survey hours of daylight for locations of interest
9th September 2024A few years back, I needed to get sunrise and sunset information for a location in Ireland. This was to help me plan visits to a rural location with a bus service going nearby, and I did not want to be waiting on the side of the road in the dark on my return journey. It ended up being a project that I undertook using the Julia programming language.
This had other uses too: one was the planning of trips to North America. This was how I learned that evenings in San Francisco were not as long as their counterparts in Ireland. Later, it had its uses in assessing the feasibility of seeing other parts of the Pacific Northwest during the month of August. Other matters meant that such designs never came to anything.
The Sunrise Sunset API was used to get the times for the start and end of daylight. That meant looping through the days of the year to get the information, but I needed to get the latitude and longitude information from elsewhere to fuel that process. While Google Maps has its uses with this, it is a manual and rather fiddly process. Sparing use of Nomintim's API is what helped with increasing the amount of automation and user-friendliness, especially what comes from OpenStreetMap.
Accessing using Julia's HTTP package got me the data in JSON format that I then converted into atomic vectors and tabular data. The end product is an Excel spreadsheet with all the times in UTC. A next step would be to use the solar noon information to port things to the correct timezone. It can be done manually in Excel and its kind, but some more automation would make things smoother.
Getting rid of a Dropbox error message on a Linux-powered PC
24th September 2012One of my PC's has ended up becoming a testing ground for a number of Linux distributions. The list has included openSUSE, Fedora, Arch and LMDE with Sabayon being the latest incumbent. From Arch onwards in that list, though, a message has appeared on loading the desktop with every one of these when I have Dropbox's client set up on there:
Unable to monitor entire Dropbox folder hierarchy. Please run "echo 100000 | sudo tee /proc/sys/fs/inotify/max_user_watches" and restart Dropbox to correct the problem.
Even applying the remedy that the message suggests won't permanently resolve the issue. For that, you need to edit /etc/sysctl.conf with superuser access and add the following line to it:
fs.inotify.max_user_watches = 100000
With that in place, you can issue the following command to sort out the problem in the current session (assuming your user account is listed in /etc/sudoers):
sudo sysctl -p & dropbox stop & dropbox start
A reboot should demonstrate that the messages no longer appear again. For a good while, I had ignored it, but curiosity eventually got me to find out how it could be stopped and led to what you find above.