NOVA Goes OSM (Open Street Map)

About 40 volunteers gathered Saturday morning at NOVA’s Reston Center to map food resources in their communities.  The Map-a-Thon was hosted by NOVA’s student ASPRS (remote sensing) chapter.  Partners in the effort were Mason’s ASPRS chapter, MappingDC, Open Street Map, and MapGive.  Mappers used Open Street Map to plot and tag farmers markets (and vendors) in their communities.  The event was open to the public and supported the Geography Awareness Week theme of food security.


Volunteers mapping Farmers Markets
Volunteers mapping Farmers Markets

Click here to learn more about Open Street Map and Geography Week.

Record Drought Reveals Stunning Changes Along Colorado River

Jonathan Waterman for National Geographic  23 NOv 2014


A boat wends its way around the curves of Reflection Canyon, part of Lake Powell in Glen Canyon. The "bathtub rings" on the walls show past water levels. PHOTOGRAPH BY MICHAEL MELFORD, NATIONAL GEOGRAPHIC CREATIVE
A boat wends its way around the curves of Reflection Canyon, part of Lake Powell in Glen Canyon. The “bathtub rings” on the walls show past water levels.

LAKE POWELL, Utah—In early September, at the abandoned Piute Farms marina on a remote edge of southern Utah’s Navajo reservation, we watched a ten-foot (three-meter) waterfall plunging off what used to be the end of the San Juan River.

Until 1990, this point marked the smooth confluence of the river with Lake Powell, one of the largest reservoirs in the U.S. But the lake has shrunk so much due to the recent drought that this waterfall has emerged, with sandy water as thick as a milkshake.

My partner DeEdda McLean and I had come to this area west of Mexican Hat, Utah, to kayak acrossLake Powell, a reservoir formed by the confluence of the San Juan and the Colorado Rivers and the holding power of Glen Canyon Dam, which lies just over the border in Arizona. Yet in place of a majestic reservoir, we saw only the thin ribbon of a reemergent river channel, which had been inundated for most of the past three decades by the lake. We called this new channel the San Powell, combining the name of the river and the lake.


We had also come to see firsthand how drought is changing the landscapes of the desert Southwest. Here, judging by the lack of conservation reform, water has seemed to be largely taken for granted. But our recent float suggests that profound changes may be in store for the region. (See “The American Nile.”)

Sweating in the desert heat, we loaded our 15-foot (5-meter) kayaks with two weeks’ worth of food and ten gallons of water—enough to last us two days. Drinking from the silty river or fecal-contaminated areas of Lake Powell frequented by houseboats was not an option (Glen Canyon Recreation Area, which includes the reservoir, is visited by more than two million people a year). The contours of our journey—where we camped, our hiking destinations, and how far we paddled each day—would be defined by the need to find potable springs.  Click here to read more.

Mapping Crime

DOUGPETE @  23 Nov 2014


The Global Security Map attempts to map the world, showing us where the bad stuff is located.  For its purposes, it tries to identify “malware, phishing, spam and other malicious activities”.

Upon your first landing, you’ll be presented with the world with countries coded from green to red or low to uh oh.

I’m a big fan of infographics to immediate share an image and message and maps have always lent themselves to visualize things.  In this case, it’s the malware that the concerned, connected computer user needs to keep in mind.

You’ll definitely want to read how the site determines the colours and the severity of the threats.  The descriptions of the threats is particularly helpful. A tool such of this opens the door for discussion about safety online.  Why would some countries be orange and red?  Why would some be green?  Is Antarctica really the safest place on the planet?

Mouse over the countries and click to get the summary for that country.


Can you find #1?  How about #219?

Don’t forget to click the grey triangles to open each category to reveal the details for each category.

It’s a fascinating look at our online world and a great conversation starter and launchpad for further research into online safety.

Python Explained

Gavin Thomas in    Python insights vis-a-vis the Raspberry computer.


There’s a lot of focus on Python for programming on the Raspberry Pi. Is this because it’s the only way to program the Raspberry Pi?

No, not at all. As we’re generally using Linux on the Raspberry Pi, just about every major programming language can be used. C, C++, Ruby, Perl and more are all completely compatible with the Raspberry Pi. You’re not really programming the Raspberry Pi with them either – you’re creating programs that will run on the Raspberry Pi.

That’s good to know, then. If that’s the case, why concentrate on Python as much as you guys and the Raspberry Pi folk do?

It really all comes back to the core mission of the Raspberry Pi Foundation: to help educate school children in computer science. This involves coding, and Python is considered an easy language to learn. It’s a language a lot of people know anyway. Plus, we have a bit more expertise in Python on the magazine, and we’re also very happy to promote the Raspberry Pi Foundation’s objectives.

What makes it so easy to use over the other languages?

Python is ‘readable’. Core variables and functions are named plainly, the structure is designed to handle a lot of white space and everything is written a lot more straightforwardly than other programming languages. What it all means is you can quickly scan some Python code and make more sense of it than other languages, which can sometimes look like a cat took a walk across a keyboard.

So readable means anyone can just look at it and understand what’s going on?

That’s not quite what it means; you would still need a basic understanding of coding and Python to recognise what specific parts mean. These can include the difference between a tuple or a list or a class and a function. These can easily be learned, though, and are generally easier to pick up than with the other languages.

It’s easy enough to teach to children?

Absolutely. It’s very similar to maths in that you’re teaching rules and methods that you can immediately produce an answer or output from. With the correct lessons, different concepts can be introduced and built upon just like anything taught in school. In fact, the incoming changes to the UK curriculum will cover coding in this exact way.

If Python’s such a simple language, does this mean it’s not very useful in the real world of programming?

That’s not the case at all – Python is used by companies around the world in ‘real programming’. It’s not the only language, though, and some companies won’t even use Python – at the very least, it sets people up to learn the intricacies of programming languages and makes learning others a little
bit easier.

Can Python interact with other programming languages?

It largely depends on the language but the quick answer is not really. There are very few, if any, projects where you’ll need to use different languages, unless they handle completely different aspects of the software. A database could be created and maintained using SQL but that’s something Python can’t handle itself anyway.

How do I create a Python program?

Like a lot of programming, you need to create a script: a file that contains all your code and tells a Python interpreter what to do when the code is run properly. You can create them in a plain text editor like gedit or even nano on the terminal and save them as .py files before testing them. The best way is to create it in an IDE though.

What is an IDE? How do I get one on the Raspberry Pi?

An integrated development environment is software that lets you create and test scripts in specific languages. You usually have a few more ways to debug your files with them as well. In the case of Python on the Raspberry Pi, you can use IDLE which is already installed and available from
the desktop.

Wait… IDLE? Python? Is that an intentional reference?

Yep, IDLE is named after Monty Python alumni Eric Idle because everyone in tech is a nerd.

I see on the Raspberry Pi that there are multiple IDLEs. One is just called IDLE and the other is called IDLE 3. What does this mean?

The standard IDLE uses Python 2, while IDLE 3 uses Python 3. They’re both two slightly different versions of Python, with 3 having a few more and different functions. Due to the popularity of Python 2, though, it’s still prevalent in tutorials and projects and included on the Raspberry Pi.

Which one should I be using?

It’s best to stick to Python 2 and therefore the normal version of IDLE. Going from 2 to 3 is not a huge deal so when the big switchover finally occurs you’ll be in a good position to learn the changes as you go.

Will the code I create on the Raspberry Pi work elsewhere?

The code is not platform-specific, so as long as you have the same modules and files on the PC you want to transfer it to it will work just fine. Some modules may be slightly different between different types of PC, depending on what’s compatible on the Pi and PC, but 99 per cent of the time you shouldn’t have
a problem.