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Geotechnical News March 2011
GEOTECHNICAL INSTRUMENTATION NEWS
GeoViewer™ Web-based Data
Management Software
Rob Taylor, RST Instruments Ltd
Introduction
GeoViewer is a data viewer originally
developed in 2000 to provide flexible
console viewing of large data sets from
ADAS (automatic data acquisition
systems). The program runs on
Windows™.
Data Source
Much GeoViewer data originates in
data loggers which transmit their data
by various logger-specific means to
files which are locally or remotely
accessible to the GeoViewer server.
Because of this file model, any file
with a public format which contains
time-stamped data may be presented in
GeoViewer: spreadsheets, databases,
comma-separated text files, GPS and
total station data, public weather data
etc.
Data Storage
RST suggests that all stored data be
as raw as possible, e.g. vibrating wire
sensors should be stored in “B units”,
and that data from multiple sources
should be kept separately in original,
maximally readable format. In the
case of logger data which is constantly
appended to a file this is by far the
simplest and most reliable approach.
Standard file server backup strategies
are used.
Historically, such an approach might
have strained the resources of avail-
able computers, but as time passes, the
power of reasonably-priced servers has
increased to the point that a server with
200 loggers communicating by dozens
of paths, 6,000 sensors, years of hourly
data, and dozens of simultaneous web
access users gives excellent perfor-
mance. At the same time, all data is in
a format that can be checked against
manual readout data and sample cali-
brated with text file and spreadsheet
tools.
Calibration and Computation
With all data storage in raw format,
calibration is typically performed on-
the-fly using a calibration database.
Numerous functions are available:
linear, polynomial, transcendental,
relational across the entire system (not
just within a logger).
Deferred calibration is a powerful
maintenance tool: if the calibration of
a sensor is found to be incorrect, the
appropriate calibration page is edited,
and the entire record is automatically
updated from the first reading.
Data Presentation
Data presentation is typically as views
which are designed for efficient use.
They may be:
• mimic views with stoplight (green/
yellow/red/blue/grey for ok/warn-
ing/alarm/alarm-off/stale data) but-
tons which “drill down” into other
views
• lists with stoplight coloured numer-
ic fields
• time series plots with one or more
channels with alarm levels, differ-
ent sampling rates
• exaggerated profiles for inclinom-
eters, tilt beam etc
• linked files: installation photos, log-
ger programs, calibrations, notes,
all one mouse click away from the
data
Alarm Functions
Full featured alarms are available
for all channels, calculations from
channels, communication status etc.
The alarms include high/low warn and
alarm levels, hysteresis, event triggers,
alarm levels computed from data,
device outputs, privilege alarm mask.
It is suggested that not every channel
be alarmed and alarms be implemented
incrementally to minimize nuisance
alarms.
Data Archive
With the low cost of data storage,
archiving may be at job end only, even
for the largest construction projects.
For permanent installations where data
goes on indefinitely, relocating (but
retaining) older data may be useful to
keep records manageable. Resampling
older data may be used to decimate
the size of on-line records, e.g. weekly
min/max instead of hourly data divides
quantity by 84, but permits historical
context to be on-screen.
Web Functionality
GeoViewer
utilizes
Internet
communications in numerous ways.
Data acquisition may use wired or
wireless web communication as a link in
a communications chain, local and wide
area networks may be used to access
data files outside the GeoViewer server,
back-up may use offsite resources.
End users may view data securely
by remote computer or mobile device,
and receive alarms by e-mail, text mes-
sages etc. Privileged users can maintain
the system from offsite, typically by
VPN (virtual private network) remote
access. Because of the limited screen
size of mobile devices, mobile-friendly
views are typically required, with large
buttons and reduced clutter.
Business Model
GeoViewer is typically sold as a
purchase/annual maintenance product;
i.e. the customer owns the product
and runs it on his or her server. The
purchase cost is based on number of
servers running (typically one), and
the number of simultaneous advanced
viewers. On-and off-site training and
assistance are available.
Rob Taylor, President,
RST Instruments Ltd.,
200-2050 Hartley Drive, Coquitlam,
BC, V3K 6W5 Canada, 604-540-1100,
