АкушерствоАнатомияАнестезиологияВакцинопрофилактикаВалеологияВетеринарияГигиенаЗаболеванияИммунологияКардиологияНеврологияНефрологияОнкологияОториноларингологияОфтальмологияПаразитологияПедиатрияПервая помощьПсихиатрияПульмонологияРеанимацияРевматологияСтоматологияТерапияТоксикологияТравматологияУрологияФармакологияФармацевтикаФизиотерапияФтизиатрияХирургияЭндокринологияЭпидемиология

Interpreting Foreign Maps

The use of foreign maps poses several problems to the land navigator. The classification and symbols for vegetation on most foreign maps are different to those used on DMA maps. The symbols that depict the various types of vegetation differ greatly from one foreign map to another.

After discussing the many difficulties and limited advantages encountered when using foreign maps, it is only appropriate that some strategy be offered to help you with the task. The DMA suggested a five-step process for reading and interpreting foreign maps

Step 1. There are generally four dates: survey and compilation, publication, printing and reprinting, and revision. The date of the survey and compilation is most important.

Step 2. Note whether the publisher is military, government, or civilian. Maps published by the government or the military are generally most accurate.

Step 3. The composition will reveal the map's accuracy. Was care taken in the cartography? Are symbols and labels properly placed? Is the draftsmanship precise? Is the coastline or river bank detailed?

Step 4. Observe the map's color. Does it enhance your understanding or does it obscure and confuse?

Step 5. As an accomplished navigator, you should already have a good understanding of your area of operations, so translation of the map's symbols should not present an impossible task. Begin to decode the various map colors, symbols, and terms. Use your notebook to develop an English version of the legend or create a new legend of your own.

Foreign maps generally use contour lines to portray terrain relief, but the contour intervals may range from 5 to 100 meters. Scales found on foreign maps include 1:25,000, 1:50,000 1:75,000, and 1:100,000. Most foreign large-scale topographic maps have been overprinted with 1,000-meter grid squares.

Дата добавления: 2015-09-18 | Просмотры: 675 | Нарушение авторских прав