0.6 - 0.7 micrometers fire centers are revealed by the presence of smoke trains, and on photographs in the band
of 0.8 - 1.0 micrometers fragments containing the plots gone by forest fires (burns) are extracted.
On space photographs and scanner images of high resolution in the band of 0.6 - 0.7 micrometers fragments
with the supposed clear cuts, and in the band of 0.8 - 0.9 micrometers - fragments with comparatively small
plots of the burnt forest are singled out.
To connect the recorded survey fragments to the topographic basis the control points located in the
neighbourhood are chosen on photographs.
Further processing of the obtained remote sensing data is done with digital methods by the image processing
system. After entering of the fragments into the system and connecting them by control points to the
topographic base they are subjected to two-stage interpretation, ending in the extraction of changes contours.
On the first interpretation stage the survey fragment of the space photograph is analysed by way of using its
combination of cartographic and forest mensuration data. The analysis is done in the dialogue regime with
visualization of graphical information on the monitor screen. The aim of this stage is to improve the reliability
of revealing the photo plots reflecting the changes in the forest fund areas as a result of forest fires and clear
cuts.
On the second stage the revealed plots on the photograph are accurately connected to the cartographic topo-
base and viewed at high magnification (with the magnifying glass) to get the information about the location and
size of plots, gone by fires, and cuts with the accuracy high enough for practical work.
The division of the process of interpreting space photographs into two different stages (viewing and detailed
interpretation) makes it possible to considerably shorten time spent on the processing and to consider in detail
only the currently changed forest plots.
The newly shown burns and cuts are determined by way of comparing the contours of burnt plots and cuts of
the past assessment periods stored in the cartographic base, and contours of these areas extracted by the space
photograph.
On the final processing stage the editing and indexing of contours of plots with changes extracted by the
photograph, their rectification into the topo-base projection, building-in into the contour network, calculation
of areas and input of changes into forest mensuration description of the considered region are done.
The knowledge of the stored in the forest mensuration base characteristics of the burnt plots and cuts referring
to the period that took place before these events allows to determine the volume of the burnt and cut timber
and to reveal main violations of the forest use order established for the given region.
In experimental testing of the method with the materials of space photographs of the East Siberia forests the
10% accuracy of determining cutting areas with the probability level of 0.85 - 0.9 was achieved.
The assessment was done by comparing the results of the detailed interpretation of space photographs with
the data about the same cuts obtained by aerial photographs at scale 1:25000.
Experience in revealing plots gone by fires has shown that even such a distinct interpretation feature as the
availability of the smoke train not always allows to detect the burnt area especially if the image of the terrain
is quite "motley", and the plots have not too large a size. It was possible to record burnt areas of more than
200 ha reliably enough. It was difficult to determine areas of plots gone by fires in marshlands of the West
Siberia.
The developed system is used in the complex of technical means Pericolor-Nova-Photomation, exchanging
information through inner communication channels.