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collected with the GPS, transforming them from central
projections into geometrically correct orthogonal projections.
The images treated in this way can be used for calculating
surfaces,overlaying vector and raster elements relevant to
tem, theme imput and handling inside a GIS. The data
originating from the survey with the GPS was also processed
by software HIFI (commercialised by SISCAM) which enable
to carry out three dimensional designing.
Data transfer Into the Forestry Informatic System
The data gathered and processed in the way described above
was further handled with the aim to be taken out and stored in
the Forestry Informatic System of the Emilia-Romagna
Regional Administration. This is a GIS, partly autonomous,
but interconnected, of the Regional Informatic System (SIR)
operating on PC in ARC-View within which, not only data-
base from SIR is stored data (point) originally from the
Regional Forestry Inventory ,but the limits and aspects of the
parks and of the State reserves and forests.
The transfer of GPS data from rover to ARC-View is done in
various stages:
1) the transfer of data from rover to PC by means of software
Pfinder supplied with the GPS system,
2) the differential corrections in automatic of data gathered
though the software Pfindet;
3) the eventual manual corrections of corrected dala using,
software Pfinder;
4) the transfer from the format by means of software Pfinder
to the format ARC-Info’
5) the transfer from the format to ARC-Info to the format
ARC-View by means of the software ARC-Info;
6) the orthoimeges produced by the ORTHOMAP system are
in format TIFF and therefore directly readable by ARC-View.
Results
Examining closely each single objective, the results can be
summarised as:
- the areas ravaged by fire were easily mapped and the
topographic precision of the survey was verified and assessed
extremely satisfactory up to the 1:5.000 scale even if no post-
optimisation of the surveyed tracks was used;
- a file, relative tothe forest fire survey, used by the command
station of the CFS, was implemented in the rover without
much difficulty, using directly the data editor inside Pfinder. It
was also noticed the uselessness of a great part of this file, for
the survey in the country, which in the GPS survey could be
simplified in the parts conceming the fire protection
procedure and a major data input (also points) of station
descriptions could be acquired;
- the survey of the two areas carried out on two separate days,
for a total of 10 complesive working hours in the country,
Was:
6 hours for the survey of the Sibano area, more complex in
form and so with longer boundaries to be covered end not
easily accessible forastry topsoil;
4 hours for the Tabina survey, more regular in form and
almost entirely covered with degraded shrubby topsoil making,
It more accessible.
The survey time takes in:
1) the apparatus preparations and setting off from the base;
2) the reaching of the area to be surveyed,
> This and the following operation can be automatic using
the option PathFinder 3.1 and Arc-View 2.1 it is,
however, inconvenient as it is impossible to transfer the
feature.
3) the mounting-up of the rover components and control of
their functioning,
4) the marking out of the fire boundaries (which was done
covering, on foot, the external perimeter of the burnt up areas
and their "zoning", taking into consideration the cultivation
typology which previously existed;
5) the return to the stand whilst monitoring the track
conditions; :
6) the dismantling of the rover components and the recharging
of the batteries and datalogger;
- the complex orographical situation of the territory (steeply
sloping, extremely irregular and numerous accessibility
problems, above all, in the Sibano area) did not influence the
time factor of the survey. Neither was the apparatus limited by
these factors. The capacity of the technician to work in
difficuk conditions, keeping constant attention to the controls
of the instrument, resulted decisive;
- the number of people involved in the country survey, was
over estimated in respect to the real needs. An optimal team
could be made up of two people, a GPS technician and the
other as a back-up and guide;
- the GPS survey presents the same problematic and time
factor for rapid ground survey and this kind of survey seems
to have the same operative limits. The minimüm dimensions,
similar to those surveyed in this work, seemed ideal for
monitoring without a too accurate planning of the mission,
Larger or more difficult areas, however, necessitate an
accurale survey programme from an operative view-point to
the logistic one;
- the pre-processing and correction of the data system did not
result particularly complex and is well handled by Pfinder.
The major difficulties were, on the contrary, found in the
corrections of the precision and in the transfer of data in
format GIS. These changes were not completely tolerated by
the program and needed the continuous intervention of the
technician. Other limits were found in the impossibility of
direct data transfer from by Pfinder lo ARC-View. This limit
made us adopt the specific mode of ARC-Info and hence
work stations and technicians would be able to manage them;
- the data processing was carried out, each time, on return
from the country survey, by a technician with informatic skills
adequate to working with Pfinder and ARC-View (in PC
297
mode) and capable of some work on ARC-Info. During the
course of en hour, corrected surface data was collected
(processing entirely done on Pfinder) while the emission of
data in ARC-View and cartographic processing required three
hours for the Sibano area and two and a half hours for
Tabina;
- the format TIFF was defined as the digitizing and archiving
format of photographic material which permits the collection
of digital material to run on PC without reducing the
informative content;
- a digital terrain model was set up starting from GPS data and
through this the archived photographic material was corrected
end georefenced;
-a complex quering of the archived photogrammes was likely
because it was possible to relate between them, and with other
types of dala;
- an orthophotomap was drawn on 1:10.000 scale of the areas
covered by forest fire to be used in the studies of the
dynamics of fire propagation
After data processing ,the following were obtained:
8) the amplitude of the areas and their boundaries which were
transmitted immediately to ‘CFS to be confronted with the
results from previous reconnaissance carried out;
b) a group of territorial elements corrected and ready to be run
on GIS;
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996