surveying iii (topographic and geodetic surveys) - Modern Prepper

separations will occur. For this reason, and because the ties between local triangulation in southeastAsia are typically weak, the India datum is probably the least satisfactory of the preferred datums.1-16. Deficiencies. The preferred datums, though an improvement over the older national datums, haveserious deficiencies. The effect of these deficiencies is that the preferred systems do not provide thegeodetic information required for intercontinental-range missiles. It is true that the HIRAN NorthAtlantic tie permits connecting the European Datum and the North American Datum. However, thisdoes not completely solve the problem, for both the North American and European Datums are relative(Figure 1-24). While in each case the ellipsoid chosen is an adequate fit in the area of the origin, neitherprovides a good fit for the entire earth. Also, the process of connecting various datums by means ofintervening datums or triangulation ties allows for errors and does not always provide agreement withnewly observed data. The surveys joining India to the European and the Tokyo Datums also presentsuch a problem. Since the preferred datums are relative and the few existing connections between thepreferred datums provide weak ties, it is not possible to compute geodetic distances and directionsbetween the systems, and the requirement for long-range geodetic information is still unsolved.Figure 1-24. The Preferred Datums are Relative Datums1-37 EN0593