How to use the Make Map options
(view map example)
- Scale map to data
- Choosing this option
means that the map created will only include the geographic region in which
the data is contained (plus a few degrees).
- Map region
- You can set an exact
region to map using latitude and longitude. If the map is scaled to the data,
the parameters of the map will appear in this section after the first map
- Large View
- A larger scaled map than
the default. The difference between the default size and "larger"
size is dependent on the size of the area being mapped.
- We have downloaded plate
boundary information from the Geological Survey of Japan site (No URL available
at this time).
- The city database is
from a site done by the United Nations Statistics Division. The city database is for geographical reference
(population data may not be current).
- Map title
- You can create your own
map title. You may leave this option blank.
- The positive numbers
zoom in, negative zoom out. The zoom function "sticks" with each
use so be sure to set zoom to "None" if you wish to redraw the map
without changing the perspective.
- Clicking on the map will
redraw the map with your click point as the new center. The new map will include
any new options you have chosen. If you have selected a zoom factor, the zoom
will center in (or out) on your click. If you wish to redraw the map without
recentering, click the Make Map button instead of the map.
Advanced Options for Event Maps
The advanced options are
just that - optional. You do not have to change any of the default settings
to make a map. We have provided these options because we realize that some users
may want to map more than one region for comparative study or to have control
over the size of the symbols used. (One benefit of controlling the "bin" options
is that maps of different scales can display event points at the same
- Top data bin
- The bin (or grouping)
that contains the largest magnitude events. Example: If you search for all
events between magnitude 5.0 and 6.0, the top bin would be the one holding
the 6.0s. The number of different magnitudes in the top bin is determined
by the bin width and/or number of bins.
- Maximum symbol size
- The largest symbol size
used to display events in the top data bin. (If only one bin is selected then
this symbol size will be used to represent all events.)
- Bin width
- The magnitude difference
by which data is put into different bins. Example: Defining a bin width of
1 will cause events with magnitudes which differ by more than 1 to be in
bins (i.e. represented by different symbol sizes).
Because you are limited
to 5 bins (see below), choosing a bin width that separates magnitudes into
more than 5 bins will result in the lowest bin holding all the "left
over" magnitudes. Example: A query resulted in a list of events ranging
in magnitude from 3.0 to 8.0. We set the bin width to be 1 and number of
bins to 4. The bins would fill like this: <6 , 6-6.9 , 7-7.9 , >=8
- Number of bins
- How many symbols you
want to use to display events of different magnitudes. Example: If you searched
for all magnitude 5.0 to 6.0 events and you wanted to display these using
only 3 bins, you might set the bin width to be 0.5. The three bins would contain
events like so: bin 1] < 5.5 , bin 2] 5.5-5.9 , bin 3] >= 6. If you
want to draw attention to depth instead of magnitude, you might consider picking
only one bin (i.e. one symbol size) for all events regardless of magnitude.
If these explanations are
not helpful, please send e-mail to for more help.