Information Technology Reference
In-Depth Information
To cope with the first problem, we refer to how Google Maps
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loads the map image
onto a browser. In Google Maps, the entire map is divided into multiple images with
different resolutions, each of which corresponds to a zoom level and a range, and are
aligned as a grid in the database. When we view a map of a specific range and resolution
on a Web browser, only the corresponding image depending on the resolution and the
range is selectively loaded from the database. The loading time is much less than that
of loading the entire image. Google Maps Image Cutter [7] is a software that divides
an image into multiple ones complying with the Google Maps format and generates
HTML codes to display the images through the Google Maps interface. We use it to
display disaster safety maps on CoSMOS.
To cope with the second problem, we use the zooming and dragging functions which
are compatible with those of Google Maps because disaster safety maps are displayed
using the Google Maps interface. Students can easily zoom out/in to view the en-
tire/detail part of a disaster safety map by using a mouse.
3.2 Linking Disaster Safety Maps to the World Map
One of the goals of the NDYS project is to create a “global” disaster safety map by
students over the world collaborating with each other. We create such a global map
by linking disaster safety maps to a world map. Each disaster safety map is uploaded
on Cosmos as an individual page, and a link to the the world map is attached using
the Google Maps API
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. The reason why we choose the Google Maps API is because
Google Maps covers the entire world, and it can be customized by utilizing its functions.
In order to embed the Google Maps in CoSMOS, we use the marker function to
create a link from a disaster safety map to the world map. The metadata of the disaster
safety map is stored in the Disaster Safety Map database, which is implemented by
using MySQL, in the following format.
[ID], [Latitude], [Longitude], [Page ID]
“Latitude” and “Longitude” represent the coordinate of the disaster safety map on the
world map. “Page ID” is the URL of the page on which the disaster safety map is
uploaded.
3.3 Posting Comments on Disaster Safety Maps
CoSMOS has a function to paste a note on a disaster safety map to support collaborative
learning over the maps.
Since a student can paste a note anywhere on the map, he/she can pinpoint a specific
part of the map in which he/she has a comment or a question. The other student who
created the map can reply to the pasted notes, so they can communicate with each other
in a Q&A style.
We utilize the marker function of Google Maps to indicate the position of note on a
disaster safety map by specifying the coordinate of the note on the map. Note data are
stored in the Note database implemented by MySQL in the format below.
3
http://www.google.co.jp/maps
4
http://code.google.com/intl/en/apis/maps/
