We are conducting basic research
on efficient delivery of GIS services over a thinwire.
Just as in serving large raster images, we believe that
active visualization servers
provide many advantages for this application.
The issues here are somewhat different
from that of serving large digital images——the underlying
data here is geometric and logical. There is opportunity
for using the visual interface as query interface, which
would call for a variety of additional search structures.
The issue of multiresolution models for GIS data is a critical one.
Our goal is to build a system that will allow users to
smoothly pan and zoom around a large geography in real time,
and to develop various tools to facilitate their exploration.
The current
java demo
covers the continental United States (48 states), with full detail
down to street level.
Users can smoothly zoom and pan across the map,
from the highest level down to street level, a zoom factor of almost
10,000. The database in compressed format is about 1.2 GB. The user
interface is composed of a tree-hierarchy of telescoping
windows, or telewindows, that was designed
to scale well as the range of zooming increases.
Here is a screenshot.
++ Eric Shaffer's
tool
at UIUC to Converting any host or domain name or IP address
to latitude and longitude.
++
Geocoding Information from
Tele Atlas North.
Thus, 251 Mercer Street, New York, NY 10012
is mapped to (Lat,Lon)=(40.728321, -073.995921)
or in deg:min:sec = (40:43:41.956N, 73:59:45.316W).
FIPS County = NY061, MCD = NY061005, Place = NY2505,
Tract = NY061005501, etc.
++
GRASS GIS: ``Geographical Resources Analysis Support
System'', an open source GIS
with raster, topological vector,
image processing and graphics production functionality.
Written in C with Java interface for various unix/linux
platforms and some Windows support.
