SIO135/SIO236 LAB 4 – Google Earth Due May 6 2010
This Lab uses only Google Earth, no Matlab. Save any images you import or marks you
make to a kmz or kml file (see problem 4) and send that file to me by email
(firstname.lastname@example.org). It would be great help if you can name your google earth homework
as following: lastname_lab#.kmz, i.e. my homework for LAB4 would be: tong_lab4.kmz
Google Earth is a useful way to look at Remote Sensing data in its geographic context.
Because it is free and can be downloaded to any computer, Google Earth is also an easy
way to share your findings with others. If you’ve never used Google Earth before, look
at a tutorial. You’ll want to change the preferences to allow faster navigating. Look at
the Rocky Mountains, the Eiffel Tower, Victoria Falls, Manhattan, and anything else
1) Learn how to create a Placemark by hand. Find where you live. Find where your
parents live. Create Placemarks for both. Notice you can immediately return to these
places by double clicking on the Placemark icon in the left panel.
2) Learn how to load a kml file into Google Earth. Download chile-earthquake_nl.kml
file from ftp://topex.ucsd.edu/pub/class/rs/LAB4/ and put it into your working directory.
The file is a compilation of maps and data about Chile earthquake of Feb 27 2010
(http://www.gelib.com/chile-earthquake-maps.htm). Try to open it and browse what’s
inside the kml file. There are many maps in this kml file and you can look at each one by
turning other maps off. Can you make the map transparent? Do the coastlines match the
coastlines in Google Earth? Can you find the location of this earthquake (epicenter)? In
later sections, we will learn how to add in new data/maps into this kml file.
For question 3) and 4), if you decide to import your own maps/data into Google Earth,
feel free to do so. It needn’t to be related to Chile Earthquake, chile-earthquake_nl.kml is
just an example.
3) Learn how to load Placemark from files. Download GPS.txt file from
ftp://topex.ucsd.edu/pub/class/rs/LAB4/ and put it into your working directory. This
GPS.txt file contains the geographic position for each GPS site in South American. It’s in
the following format:
Longitude, Latitude, site ID
Open this file using Google Earth. (File -> Open…) Where is the GPS site that closest to
the Chile earthquake (epicenter)? Can you use ruler tool to measure the distance from this
GPS site to the epicenter? Surprisingly, this GPS site recorded more than 4 meters of
ground movement within seconds during Chile earthquake. Actually, instead of loading
GPS.txt file we provide, you can choose your own placemark to load into Google Earth.
4) Learn how to import image overlay and place it in right place. Download
phase_mask_ll.png file and readme file from ftp://topex.ucsd.edu/pub/class/rs/LAB4/ and
put it into your working directory. It is an interferogram made by differencing two scenes
from an active-source microwave radar (like the front cover of your book). It
shows ground motions during Chile earthquake of Feb 27 2010. Import this image into
Google Earth (use Add Image Overlay) and position it correctly using the NSEW edges
(see readme file). Adjust the transparency so that you can see both the interferogram and
the Google Earth imagery. Do they line up? Actually, instead of loading
phase_mask_ll.png file we provide, you can choose your own image to load into Google
Earth and you will place the image into right place by yourself.
5) To save your work, create a new folder in the Places on the left panel. Put any
Placemarks or Images you have created or imported into this folder. Right click on the
folder and choose Save As. Default is a kmz (binary) file format. Send this file to me.