Friday, August 29, 2014

Explaining Map Projections with GMEL (Google Maps Engine Lite)

This is the second post in which I write up ideas I've lifted from colleagues at the Google Teacher's Institute I went to in Pittsburg earlier this year.  This time I'll work up an idea I got from Josh Williams, author of  Use the polygon (shape) function in google maps engine lite to illustrate distortions produced by projections.

Background to Projections:  A problem with all flat maps is the 'orange peel problem' - try as you might there is no way to peel an orange and get the peel to lay flat without stretching it (if it was made of rubber) or ripping it into very small pieces.  All flat map representations of our globe are therefore distorted in some way.

0] You may like to start with some demo of actually peeling an orange and trying to get the peel flat.

1] Using Google Earth show students Greenland and South America to illustrate the size difference.  You might like to use the ruler tool to actually measure the width/height.  South America is much the larger.

2] Now flip to Google Maps Engine Lite and create a new map by clicking the button (you'll need to login to Google if you aren't already)

3] Name the map 'Illustrating Projections' or something similar

4] Point out to the students the difference in apparent size now, why would Greenland appear to be the same size as the much bigger South America?  The answer is distortion.

5] Using the 'draw a line tool' (a line separated by circles in a button under the search bar) click and release four times to create a big square covering Brazil.  It will have circles at the corners to show it is the item you are editing at the moment.

6] Tell the students you're now going to drag it northwards over Greenland and that the surface area it encloses is going to stay constant.  Get them to predict what is going to happen to the square in a sketch on paper.

7]  Now click the square so it has circles (being edited) and drag it northwards.  The distortion shows up in three ways:
a] it gets bigger
b] it gets wider at the top at the bottom as the distortion increases closer to the poles
c] edges become curves, again, due to the distortion increasing as you go north.

8] Process with students, e.g. I'd ask if anyone got all three.

Thursday, August 14, 2014

Auto tours and Tours Love at Google Geo Teacher's Institute

So I'm not long back from being a trainer at Google Geo Teacher's Institute (GGTI).  Google kindly paid for me to fly out and put me up in a hotel so I could take part and I was part of a team advising Google on its GeoEDU program.  I can't tell you much about the advisory meeting but the GGTI is worth discussing:  It was training as much for me as for everyone else as I got to drop in on my colleagues sessions and pick up tips.  I thought I'd do a couple of blogs on what I picked up:

Automatic Tour for Student point review: An idea of Ben’s ideas that I really liked was getting students to all contribute a Google Earth point (saved as a KMZ file) and the tutor visits each one in turn to discuss.  An example would be 'find me a sand dune' then the tutor reviews if the points really mark sand dunes.  The tech bit is to put them in a folder and running an automatic tour.  To do it:

1] Get students to send you points in answer to a question by saving them and sending them to you.

2] Drag the points into a folder

3] Click the folder in the places column (it turns blue)

4] Click the play automatic tour button (not the normal tour button).  It's at the bottom left of the places column; a folder icon with a black triangle alongside it.

You will fly from point to point with a fixed time interval.  I wouldn't use this for a normal tour (a flight over a long distance should take longer than one between two closer points) but showing each student's point to the class and commenting on them will engage the students.

Love for Google Earth Tours:  What came out of both the GeoEDU advisory meeting (15 or so Google Geo education specialists advising Google on the future of their tools before GGTI) and the GGTI was that educators LOVE Google Earth Tours.  As someone who’s advocated them for education for a long time I'm really pleased to see people's interest.

There are now two ways to create Google Earth tours, with the Google Earth client and with Google Earth Tour builder. I thought I'd summarise the differences for you:

Characteristic     Google Earth Tours      Tour Builder
Ease of use           Pretty good                      Best
Editable               Yes but very complex     Yes and easy
Metaphor             Movie clip                       Powerpoint slides
Use offline?          Yes                                  No
Audio                    yes.                                 No
Layer control.      Sophisticated.                 Basic

In short, if you are used to google earth tours then don't bother switching but if you're just starting then tour builder is probably easier.