ICEMAP - Information to Ships in Winter Traffic
by Robin Berglund
ICEMAP is an application developed by VTT for interactive design
of ice charts. It is in operational use at the Finnish, Swedish and German
Ice Services, providing valuable information for winter traffic navigation.
In wintertime the ice services in Finland, Sweden and Germany produce
ice charts daily. The chart is drawn using international symbols showing
ie different types of ice areas, their thickness, leads, cracks and also
where the icebreakers are situated. Earlier the chart was drawn manually,
then redrawn before being printed and sent to the ship owners, brokers,
ships and authorities. In all there are hundreds of customers using the
ice chart in each country. The value of the ice chart is determined by
its accuracy and validity. The realtime aspect is important as the ice
situation changes over time. ICEMAP speeds up the production of high quality
charts that use remote sensing information.
Satellite images is the base for Ice charts
The ICEMAP is a UNIX-workstation based application that integrates the
functions needed for interactive production of ice charts. Digitally stored
satellite images from weather or radar satellites can be called up on the
workstation, enhanced and used as basis for the drawing. The images are
automatically remapped to the projection used in the ice chart (Mercator),
if needed. Scaling and positioning of the image is also done automatically
based on resolution and position information stored with the image header.
Ground observations (temperature measurements) can easily be imported from
a text file and used for automatic calculation of isotherms on open water
regions.
Vector based drawing makes editing easier
ICEMAP is based on a polygon network philosophy, ie the areas representing
different types of ice are polygons with shared borderlines. This facilitates
editing of the chart and speeds up the production, because normally only
part of the ice information has changed from one day to another. The user
draws the borders between different types of ice. The areas are then determined
by automatic identification of closed polygons defined by the user drawn
borderlines and permanent coastlines. The ice areas can be individually
selected and given a hatching according to the ice type of the area. When
editing an area, the new borderline is drawn, then the old borderline is
deleted.
Automatic send out to customers
The standard ice charting symbols can easily be added just by selecting
the proper symbol from a toolbar and then placing the symbol by clicking
on the ice chart. The complete ice chart is normally printed out on paper.
By using conversion-routines, a high quality digitally generated telefax-version
can be produced. The FAX-version enables automatic send out to regular
customers or can be used in combination with a CallFax service for more
widespread use. The ice chart information can also be output in a geocoded
grid format. In this way sea surface temperature and ice property information
can be utilized as input in local weather forecast models as well as for
producing ice statistics for research purposes.
Please contact:
Robin Berglund - VTT
Tel: +358 9 456 6018
E-mail: Robin.Berglund@vtt.fi
