As the fixed elements of occurrence of the avalanche, the authors defined vegetation, degrees of inclination, direction and type of the slopes which are able to measure or interprete mith non-snow covered aerial photos.
Using these elements, every slope which is devided by ridge and drainage classified 84 patterns.
With snow covered aerial photos interpreted avalanches, and then calculated the statistical probability of occurrence of the avalanche for every pattern.
If such fixed elements are able to measure or interprete, the probability of the occurrence of the avalanche would be estimated at everywhere by means of this result.

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Results of snow avalanches reflected over the roads in a snowy mountainous area were examined by mesns of aerial photographs.
The topographic elements regarding usual courses of snow avalanches were interpreted on the aerial photographs taken in non-snow season, and velocity variation and suspending points of snow avalanches on these courses were calculated with various coefficients of kinetic frictions.
On the other hand, the suspending points of svalanches on these courses were observed and measured on the aerial photographs taken in snow avalanch season.
By using these results, the coefficient of kinetic friction of snow avalanches in the region was estimated, and velocity, kinetic energy per unit volume and impulsive force per unit area of snow avalanche on the roads were estimated for each course of snow avalanche.
Moreover, debris depth and volume of snow avalanche at each course were measured by comparing the aerial photographs taken in deepest snow season against those taken in snow avalanche season.
Calculation of velocity, energy and impulsive force and measurement of depth of debris and volume of the snow avalanche at each course in the region will give the rank of the snow avalanche, and will contribute to plan the highway course.

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The structure of the terrain is being constantly changed by continuous geological processes. A corresponding ground plan cartography is a essential basis for a clear representation of the detail of the terrain structure. A terrain photogrametric representation is notable for the sharp measurements and mappings of the irregularities corresponding to the actual detail of the terrain surface.
For the measurements and mappings of the terrain surface by mean of a photogrametric survey, the ground and picture control points are inevitable and those are surveyed through triangulation and analytical triangulation respectively. Actually, it is very difficult to get adequate number of ground control points within the changing area whose speed of changes are very fast and also to apply process of analytical aerotriangulation directly to the picture control points survey for the terrain photogrammetry, because a serial pictures like those for aerial photpgrammetry are not available commonly due to topographic conditions. In short, bridging of the models must be considered instead of that of pictures.
The authors, here, examined analytical picture control points survey for the terrain photogrammetry experimentally. The base-distance ratio which corresponds to the base-height ratio in the aerial photogammetry is usually very small and it affects largel to the accuracy of the measurements. When forward intersections from the known camera positions are applied, corrections for inherent errors of the phototheodolite and distortion of camera lens must be severely considered.

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Several physical sources of errors have been neglected in photogrammetry because of their negligible effects compared to the required accuracy, for example, the minimum size of sensitized particle of film, tangential distortion of lens, irregular film shrinkage, image movement due to the motion of aircraftetc.
But several of them should not be ignored if the higher accuracy is considered, and some of them often produce larger errors than commonly believed.
They shall be pointed out, criticized, and estimated about their effects and correlations, some of them such as colour abberation, and image movement, result the error greater than 30cm, which can not be reduced by simple change of photo-scale.
As the conclusion, reduction of errors beyond 30cm can not be obtained for any photoscale, unless necessary physical considerations are given to those physicalphenomena.

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To interpretate photographs can be said to interpretate what are taken or printed on filmes or on photographic papers.
When we take all things (objects) in cosmos and make images of those, in this case, those contain not only visible ray and invisible ray, but also visible ray can not be recognized, the relation between such objects and images of those make correlation.
In this case, we have to analyze images by using index which comes from a law between objects and photographs (images) and also, confirm what are taken on photographs by using the synthetic effect (result) of analysis.
In those factors, there are factors of proximaty, factor of good form (good continuation, symmetry, closure, connontate) hue, lightness, saturation, quatify and intensity.
But, this time I should like to report about applications of photographic interpretation by using Panchromatic, Rontgen, False Color Film, etc.

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