SIY2.TXT Write a Land Description from a Map 19 Chapter 2 Write a Land Description from a Map For this chapter you will need: a) Silva Ranger type 15 compass, available for $40 from CAVE Inc, 1/2 Fast Road, Ritner, KY 42639. 606/376-3137. If you do not have a Silva Ranger compass, then you may substitute a circular protractor and a ruler. You could even make do with a schoolchild's protractor and ruler, but you won't like it. b) These instructions, c) Pencil & notepaper, d) The maps which you plotted in Chapter 1 or 1_C. You will NOT need: a) Any land, b) Any land description, c) Any assistants, d) Nor to leave the comfort and safety of your kitchen. e) You don't even need this computer, except to make a printout so that these instructions can be doodled with a pencil. Label your notepaper "Data measured from Map 1". Make column headings, "TO FROM COMPASS TAPE COMMENTS". Get out the map which you made from the data of Table 1. Station 0 is the starting point. On the first line write "0" for station TO, "0" for station FROM, 0 for the COMPASS direction, and 0 for the TAPE distance. Now you have started somewhere. Onwards. TO 1, FROM 0. Lay your compass on the map next to station 0. Turn your compass so that the mirror points in the direction of travel. Slide the compass so that the edge of the compass base aligns with the line TO 1, FROM 0. Now turn the compass dial so that the red and black arrow points north on the map and the black lines inside of the dial align with the north-south lines on the map. Remove the compass and read the COMPASS direction under the index blob. Record this number in your notes. SIY2.TXT Write a Land Description from a Map 20 To measure the TAPE distance, use the ruler on the base of your compass. Remember, this ruler is graduated in twentieths of an inch, not sixteenths. Fill out your table of data. At each station, record the station TO, the station FROM, the COMPASS direction, and the TAPE distance. Now compare this table with Table 1. They should be the same. How close is close enuf? For now, 5 degrees and 5 hundredths of an inch. For serious work you can be accurate to 1 degree and 1 hundredth. Any boundary on a map can be described as a land description by this method. 1} Start someplace. 2} Then measure the direction and distance to the next point. 3} Repeat step 2 until you have your land description. Any point on the map, such as the location of a building, well, or cave can be described in this way. Draw a line TO the point FROM a point which you have already located. Measure the direction and distance. The station FROM need not be THE previous station. It need be only A previous station. Be sure to keep track of the station FROM when you write your land description. Now label another table. The name of this table is "Data measured backwards from Map 1". Write the standard column headings, "TO FROM COMPASS TAPE COMMENTS". Add another column, "compass backwards". Start at station 4. TO 3, FROM 4. Measure and record the compass and tape the same way as you did before. In addition, at each station take another compass direction reading with the red and black arrow pointing backwards. Pointing south on your map. Record this direction under compass backwards. Compare the land description going forwards with the one going backwards. Notice that you have the same compass and tape (or close enuf) going in either direction around the map. They are in different places, to be sure. The value of "compass backwards" can be calculated. Simply add 180 to, or subtract 180 from, the compass reading going in the normal direction. Take the choice which gives the answer between 0 and 360 degrees. Play around with this until you are convinced that you can translate map into land description, and land description into map. Forwards and backwards. Fluently. And when you get confused again, draw yourself pictures until you are unconfused. No magic. Magic is for such as magicians and politicians. It will get a surveyor or a scientist into BIG trouble. Don't.