Photographs must also be verified by verification
The use of “ground photos” as evidence to prove the existence of some old things is common in cases of land-based litigation and adverse possession. These photos are mostly provided by the occupants, and the purpose is of course to prove that a certain house or a certain site has existed for a long time or is under his control. It is a pity that such photos lack more than enough landmarks to identify, and it is difficult to make any proof of the location of the things.
Maybe some photos do have some things that can be found from aerial photos or old maps, and some clues can be calculated in comparison with the techniques, so as not to be useless. However, such photos can be encountered without any demand. The surveyor has only tried his best to compare the ground photos with the aerial photos and the old maps, and then look for similar links.
If it is a comparison work, it mainly depends on two major factors. The first is to compare the photos at the same time, the second is to understand the perspective effect of the ground photos, and the similarities and differences of the aerial view of aerial photography or drawing.
Regarding the first element, the surveyor must of course know the date on which the ground photograph was taken. If the date is directly displayed on the photograph, it is of course ideal. Otherwise, it is assumed that the subject is true, and the pedestrian clothing and the cityscape, or the architectural form and the people’s landform are observed. As for the calculation, the report on the text is of course accompanied by a statement that is so inaccurate or inaccurate. Once the time of the ground photo is confirmed, the next step is to find aerial photos and old pictures of the same period. This should not be difficult. Since 1963, the Survey and Mapping Office of the Lands Department has taken aerial photographs. As for the map, it is constantly drawn. Although the refurbishment map is not as frequent as the aerial photography, there is no shortage of maps printed on time. Therefore, it is generally no problem to find aerial photos or old pictures at the same time as the ground photos.
As for the second element, it is related to the correspondence between ground photos and aerial photos, but it is necessary to understand the geometric characteristics of these two types of photos (including maps), and then use mathematical analysis to make use of the measurement.
If it is only for the general observation and common sense that only the ground photos and the aerial photos or the old pictures “see” are obtained, the need for proof does not stop there. In fact, the analysis of the photos needs to be deeper. This will discuss the geometric characteristics of various photos and maps.
First of all, the ground photos, which show what is seen from a point on the ground in a certain direction (this is the case of traditional shooting, in line with the nature of the old photos, not including modern new styles). Wide angle, loopback shooting and other ways of deformation). Nearly large and small, parallel lines are concentrated at a vanishing point (Vanishing Point), etc., which has been recognized by the public and does not have to be renewed. However, it is emphasized here that it is not applicable to measure the distance on the ground photos. This is definitely The biggest difference between the maps.
As for the aerial photos, although they are also overlooking the landscape from a little, they should contain the same perspective properties as the ground photos. They are also small in perspective, and the objects are deformed. However, because these photos are taken from thousands of feet or even higher, There is no close-up in the middle, but the landscape is similar to the plane, which is close to the map, and is absolutely different from the ground photo. Another point is that the ground photographs are familiar to our daily life. On the top of the building, we can see the walls and windows of the building, or the branches of the flower branches. It is not like the roof of the sky, or the grassy forest. One piece, correspondingly, may not easily recognize the same thing.
In terms of maps, the lines are clear and the distance angles are accurate. If there are text comments, it is more clear, but sometimes such clear lines will have corresponding misunderstandings. For example, some solid lines in the map represent things such as roadsides or ditches, and it is thought to be a list of objects that are visible to the eye. However, on the ground, this roadside may not be the boundary of the soil, but the edge of the grassy road with undulating slopes, and it is covered with flowers and leaves, which are presented in the ground photos, which can only be faintly discernible, so in the whole, the ground photos, The aerial photos and maps are corresponding to reading. It is not straightforward to engage in, and it is necessary to use geometrical mathematical analysis.