Field Mapping Terminal Data Preparation And Instrument Structure Design Research

In the 4S integrated system project of the Digital Space Research Center in Huazhong Normal University. the author is responsible for the preparation of the preliminary data for mapping and the field mapping terminal design of the outline, internal structure and functional software designing.This paper all the work based on it.The traditional method of field mapping is that the field collects data which is then handled by the office. But, our 4S integrated field mapping terminal can integrate the field work with the office work. Both the traditional and the 4S integrated method have to collect data, and it is necessary to prepare for the data before it is collected. Therefore, data preparation is an extremely important project in field mapping.Shadowgraph is indispensable during the preparation of data. We usually use the line map, aerial image or satellite image to annotate. Line image is unable to represent the actual topographic features in an intuitive way. Only the aerial image or satellite image can truly and objectively reproduce everything of the surface and include very abundant information. However, aerial image or satellite image usually keep central projection or conformation of other projection with the surface instead of similar and simple constriction. Thus, it is certain that there is deformation in these images caused by oblique photograph and solid relief. If we can revise these images as photographic plan or ortho-photo map, it is very valuable for their application in geographical information system (GIS).Currently, there are some methods to revise the ortho-photo map as the follows:1. A correct method:in a correct pictures within the scope of operations, if any like some projection difference all does not exceed mapping range err-limit requirements, such a region called the flat area, can use a polynomial fitting correction method for correcting this picture.2. Zoning in a correct method:according to the topography, within the scope of this picture will be divided into several assignments section elevation with area (particularly suitable for slope gentle hilly region with the change of each area), make the area caused by poor undulating terrain is less than the value of the projection rules. For each area area, then respectively as correct sun enchase become a piece of correct picture.3. Differential correct:use a small enough area as correct units, and according to the correct units to control the ground actual elevation to realize corrective elements, from central projection of the right to the positive shoot projection transformation. Realize differential correct in two different ways. (1) the optical differential correct:by using computer control is to shoot projectors, is making analytical photogrammetry stage of development is the main method of projective like maps. (2) digital differential correct: digital images directly using the computer to each like yuan differential correct. Adopts mainly the second approach.This paper improves the method of digital differential correction:introducing the anchor grid and variable grid model based on the undirected digital differential correction which is found on collinearity equation, and then interpolating a polynomial, which can not only reduce the error but also improve the accuracy and develop the correction rate rapidly.At the same time, a field mapping terminal is designed and developed according to the ergonomic. This paper mainly introduces the designs of the outline, structure and application software of the field mapping terminal.