Capturing, Animating and Making Measurements from images found on
the Internet, Using GIF
Converter and NIH
When images found on the
"net" need to be saved and then animated to gain a "change
through time" perspective, the following instructions should be
- After the image has been
downloaded to your computer screen go to File on the menu bar. Scroll
down to Save As..., and save the image as a Source file. When naming
the images, be sure to number them in chronological order. This will
assure you of a true representation of the data change as a function
of time. The images will need to be "opened" in the proper
order for this to take place.
- When you have the data set
you desire (We suggest between 5 and 7 images) you will need to open
them with the software GIF
Converter or Paint Shop Pro (for
- Double-click on the
icon, click on O.K. on the order form. Go to the menu bar and choose
- Then you click on the
file you wish to open. Go to Save As... and choose TIFF file from
the choices provided under File Type. The images must be in TIFF
or PICT format to allow you to use the NIH software to animate your
images. Converting the images to TIFF format will use a lot of
memory. That is the reason for limiting the number of images
to between 5 and 7.
- After they have been
saved as TIFF or PICT files, close GIF Converter program.
- Open the NIH Image software.
You will have better results if you have the FPU (floating point unit)
version. If you don't have the FPU version, go to the NIH site and
download the fat binary version. These directions are written for
the FPU version.
- After NIH is open then
go to File and choose Open. Open the images in chronological order.
- After this is complete,
go to Stacks and choose Windows to Stack. Then go to Stacks and choose
Animate. You should see the images presented on your screen one after
the other giving the illusion of movement.
- The numbers 1-9 slow down
or speed up the animation respectively. You can use the < or >
keys to scroll through the images one at a time.
Another feature of NIH Image,
is the ability to make measurements on the images that are accurate.
These include but by no means are limited to lengths, areas and densities
of pixels. Once you start to explore this software you can find many
applications for it. Here are instructions for setting the software
up to make length and area measurements. You can then use these to predict
the speed of air masses, or crustal plates for instance. The areas of
air masses or volcanic features can also be determined. Feel free to
have the students do ALL of these after you familiarize yourself with
These brief instructions
will allow you to calibrate NIH and make measurements of features found
on an image.
- Open NIH and choose the
Line Tool (diagonal dashed line with an arrow head under it).
- Next, measure a prominent
feature (sometimes there is a scale) on the image, by drawing a line
with the Line Tool.
- Go to Analyze, and Set
Scale. The length that corresponds to the line you drew (in number
of pixels) is displayed in "Measured Distance". The "Known
Distance" catagory is highlighted. Enter the known distance here
(from a map or other source) then choose the correct units from the
choices given... kilometers, etc.
determine velocity, determine the total distance the storm travels
and divide that by the total time in hours between the first and last
image. The movie will look better if images are downloaded at about
the same time each day.