Symposium on Remote Sensing for Dn ^^nrces Development and Environmental Management / Enschede / August 1986
569
Comparison between interpretations of images of different nature
G.Bollettinari
Morfogeo s.a.s., Ferrara, Italy
F. Mantovani
Ferrara University, Italy
ABSTRACT: Data obtained analaizing images of different nature, are described to interprete from the neotectonic
point of view some geomorphological feactures of the central and northern area of Perù. The purpose of this pa
per is the research of the relations ship between photointerpretation, obtained data and their reliability.
Particularly merits and shortages,interpretative limits, and the fitness use of each type of images for the over
mentioned work, will be described.
RIASSUNTO: Vengono descritti i dati ottenuti analizzando e confrontando immagini di differente natura, con lo
scopo di interpretare in chiave neotettonica le caratteristiche geomorfologiche dell'area centro settentrionale
del Perù. Scopo della presente nota è la ricerca dei rapporti intercorrenti fra fotointerpretazione, dati rica
vati e loro attendibilità. In particolare vengono sottolineati i pregi e le carenze riscontrati, per ciascuna
immagine, al fine di tracciare i limiti del dettaglio interpretativo e la destinazione d'uso più idonea.
1 INTRODUCTION
The following note is in reference to the preliminary,
photointerpretative phase of a multi-faceted study
aimed at identifying the principle neotectonic featu
res of a high plain area in the Peruvian Andes.
In particular is here analyzed a photointerpreta
tion process applied to different types of images and
the morphoneotectonics classification also used. At
the end, the various advantages and disadvantages of
each type of image is underlined, indicating any limi
tation in interpretative detail and, based on the re
sults, the use to which it is most suited.
2 PHOTOINTERPRETATION PROCESS
The area studied is in the Peruvian Andes N 10° Lat
S within a 100-Km-wide area extending approximately
400 Km NNW-SSE and including the Andean high plain.
The following documents were used:
a- LANDSAT images, average scale 1:250,000, spectral
band 7;
b- LANDSAT F.C.C. (false colour composite) images
obtained by automatic procedure of spectral bands 4,
5 and 7, average scale 1:250,000;
c- SLAR black and white photomosaic images, average
scale 1:100,000;
d- Panchromatic black and white photomosaic aerial
photographs, average scale 1:100,000.
The procedure followed two successive phases of the
photographic documents available. The first phase
consisted of a field assessment of those photoalignm
ents of certain natural origin to which a tectonic
meaning could be attributed; that is association with
faults or fractures. The second phase consisted of a
classification of the natural, tectonically signifi
cant photoalignments in the above-mentioned field:
those which were not fully developed were eliminated
unless fully aligned or associated with other alignm
ents .
2.1 Phase 1. Assessment and distribution of total
field
For assessment and distribution of the tectonically
significant natural photoalignments of the total field
the procedure was as follows:
a- Interpretation of the black and white LANDSAT
images;
b- Interpretation of the F.C.C. LANDSAT images;
c- Interpretation of the SLAR images;
d- Interpretation of the panchromatic black and
white photomosaic.
In particular the basically straight alignments as
well as circular areas were separately identified for
each type of image from their photographic and/or
morphological expressions. The former were seen as
variations in tone, texture, structure, contrast,
glossiness, etc. of the object. The latter define va
rious alignment patterns: lithological (contact bet
ween different lithotypes), structural (dip and stri
ke, faults, fractures, etc.), hydrographic and orogra
phic (water courses, valleys, watersheds, escarpments,
etc.).
2.2 Phase 2. Classification of photoalignments from
the total field
After assessment of the photoalignments had been com
pleted they were classified on the following basis:
a- continuous photoalignment planimetry;
b- correspondence of the photoalignments in the dif
ferent images used.
