JCSM Shareware Collection 1996 September

home *** CD-ROM | disk | FTP | other *** search

/ JCSM Shareware Collection 1996 September / JCSM Shareware Collection (JCS Distribution) (September 1996).ISO / bother__ / sly253a.zip / siy1.txt < prev next >

Wrap

Text File | 1995-03-04 | 24KB | 584 lines

SIY1.TXT Plot a Map from a Land Description 10 Chapter 1 Plot a Map from a Land Description For this chapter you will need: a) Silva Ranger type 15 compass, available for $43 + $5 shipping & handling from CAVE Inc, 1/2 Fast Road, Ritner, KY 42639. 606/376-3137. If you do not have this item, then you cannot execute these instructions. Instead, you must use the instructions in Chapter 1_C, "Plot a Map the Cheapie Way". b) These instructions, c) Pencil & note paper, d) Calculator. A common calculator makes the arithmetic a lot easier. If you don't own a calculator, I suggest that you purchase one. The cost is between $2 and $10, available almost everywhere. The most significant difference amongst calculators is the quality of the key pad. Everybody skip the fancy math the first time. I find a hand calculator to be a lot more useful than a pop up "calculator" on a computer. I personally use a Sharp EL-510S (solar) and a Sharp EL-506A (battery). You will not need: a) Any land, b) Any land description, c) Any assistant, d) Nor to leave the comfort & safety of your kitchen. e) Your computer, other than to print a printout of this chapter. Forewarned thrice!!! Don't let the instructions which come with the compass scare you off. If you do read their Instruction Manual, then tell me what you think of it. SIY1.TXT Plot a Map from a Land Description 11 All that you really need to know is that the red end of the compass needle points North. Because so many people kept forgetting this fact, the New and Improved Silva Ranger Compass Type 15CL has the north end of the north arrow on the compass painted red. Send your adulations to Silva Compass, Binghamton, NY 13902-1604. They even have a Customer Service Office at 800/572-8822. Open the compass. There is a graduated dial. Note that there is a mark every 2 degrees, with every 20 degrees labeled. Grab the dial and twist it around. There is an index pointer line on the compass base under the mirror. It points to the compass reading on the compass dial. The New and Improved Silva Ranger Compass has done away with the index line, and has only an index blob. Read the compass reading. Read it to 1 degree accuracy. Use a magnifying glass if necessary. What is the compass reading? Write the compass reading down on a piece of paper. Is this the correct compass reading? I can't tell from here. You gotta check your own work, starting right now. Read the compass reading again. Compare it with what you have written down on your paper. Turn the compass dial and read it again. You can also set the compass reading on the compass dial to any reading. Set the compass reading on the compass dial to 40 degrees. If there are four 40s on your compass, this is because you have a compass which is graduated in quadrants. You thought that you knew better than I, and ordered a quadrant compass against my advice. The methods for converting between the two systems of measurement are covered later in these instructions. See page 17. There are two distance scales along the sides of the compass base. One is graduated in twentieths of an inch, the other in millimeters. There are two more scales on the new Ranger, marked 1:25000 and 1:50000, which can be used to measure distance on metric topo maps. There is a compass needle which points North. You need to know that the red end of the compass needle points North. There is a device to internally adjust for magnetic declination. The declination adjustor is the brass screw on the dial at 45 degrees. SIY1.TXT Plot a Map from a Land Description 12 Turn the declination adjustor with the screw driver on the lanyard. The declination is read on the black declination scale under the tail of the black arrow. Set the declination to 0 for now. If you have an old Ranger, then the declination is set under the north end, the screwdriver is located on the safety cord, and the scale is red. It makes no difference, but it might be confusing to set the north declination on the south end of the compass if you don't know what you are doing. A survey station consists of some point with an individual name and location. The survey station may be located on the land, in a land description, or on a map. Survey stations on the land or on a map are connected together with lines, similarly to a "Connect-the-Dots" puzzle. These survey stations might or might not be at the corners of the property. Survey stations in a land description are connected by a set of instructions telling you how to find the next station. TABLE 1 Line Station Station COMPASS TAPE Comments TO FROM degrees hundredths of inches 1 0 0 0 0 You gotta start somewhere! 2 1 0 40 200 3 2 1 122 170 4 3 2 193 224 5 4 3 305 271 This is supposed to be the same as station 0 Look at Table 1, Line 1. The station is named "0". This is the station TO which you are surveying. The station FROM which you are surveying is also named "0". The station refers to itself. The COMPASS direction to TO from FROM is 0. The TAPE distance is also 0. SIY1.TXT Plot a Map from a Land Description 13 Each station must refer to either some previous station or be given some arbitrary location. Be sure that you start someplace. The best directions in the world are worthless if you don't know where you are starting. Have you ever asked for directions in Rural America? If so, you are familiar with directions which start at no where. Convert to now here. Line 2 of Table 1. The station TO is named "1". The station FROM is named "0". The COMPASS direction is 40. Set the dial on your compass so that the compass reading is 40. Isn't this easy? The TAPE distance is 200. In this case 200 hundredths of an inch. Now get out Graph 1. This is 5 to the inch graph paper. When you get around to using CAVEMAP2 you will find Graph 1 there. Or you could register this disk and I'll send you the graphs. Meanwhile, any piece of lined paper can be used. Draw an arrow along one of the lines and write an "N" near it. My graph has cheater lines on it, but they are not necessary. Turn the graph paper so that the North Arrow points up. Away. To the top. Unless there is some very good reason not to do so, always put North at the top of your map. This cartographic standard makes it much easier to keep the map orientation fresh in your feeble little mind. You will learn to <*!HATE!*> maps with North in any other direction. Put the compass on the graph paper. Now turn the compass so that the red and black orienting arrow points the same way as the North Arrow on your map. Your compass is now oriented with the map. If you need to be more exact, use the black meridian lines inside of the compass dial. Align these black lines with the north-south lines on the graph paper. The compass needle is pointing towards Magnetic North on Earth. If you have an old style Ranger, then these lines are red and the arrow is all black. Same difference. Now orient the map with the Earth. Turn the whole graph paper, leaving the compass on the paper. Turn the paper until the red and black arrow inside of the compass dial lines up with the compass needle. The New and Improved Upgraded Foolproof Silva Ranger Compass Type 15CL has a red head on the arrow so that you can remember which end is north. Those with the old fashioned Ranger must remember "The arrow head and the needle red." For now you can ignore the orientation of the map. Don't let the compass needle confuse you. SIY1.TXT Plot a Map from a Land Description 14 Turn the graph paper so that the North Arrow points to the top. Put the compass on the graph paper and turn the compass so that the red and black arrow points the same way as the North Arrow on the map. Slide (don't twist) the compass until the ruler edge of the compass goes thru where I have labeled an "x" with the name "0". Now line up the black lines inside of the dial with the north-south lines on the map. Be sure that the ruler edge of the compass still goes thru the x. Now draw a line along the ruler edge, starting at the x and extending towards the mirror. This is the plot of the compass direction. The COMPASS direction is 40 degrees. The TAPE reading is 200. That is 200 hundredths of a inch. The inches ruler on the side of the Silva Ranger has a mark every 5 hundredths, a longer mark every 10 hundredths, and is labeled every 50 hundredths. This is NOT a sixteenths ruler. Use the ruler to measure off 200 hundredths of an inch along the line representing the 40 degree compass direction on your map. That's exactly 2 full inches. Start at the "x" which is labeled "0". You will find it more accurate (and also more confusing!) to start measuring at the 1 mark on your ruler. Make an "x" 200 hundredths out the 40 degree direction line from station 0. Label this station "1". Congratulations! You have just plotted your first station. Wasn't that easy? If you can do it once, you can do it twice. On to line 3. The TO station is 2. The FROM station is 1. The way to get to TO from FROM is to go in a COMPASS direction of 122 degrees from North, a TAPE distance of 170. Set the compass reading to the compass direction of 122 degrees. Put the compass on the map, orient the compass to North, ignore the compass needle, and slide the compass until the edge passes thru the "x" labeled "1". Align the black lines with the north- south lines. Draw the 122 degree direction line on the map. Now it gets tougher. The TAPE distance is 170 hundredths of an inch, measured along the direction line. Remember, the ruler is more accurate if you don't start at the cut corner. Put an "x" 170 hundredths out the 122 degree direction line from station l. Label this station "2". You can locate the station more accurately if you first mark the spot with a tic, a little short line out from the proper spot on the ruler. A sharp pencil helps too. Wasn't that easy? SIY1.TXT Plot a Map from a Land Description 15 If you can do it twice, you can do it thrice. Line 4 gives the instructions on how to locate station 3. Plot the location of station 3 on your map. Mark it with an "x" and label it "3". Hopefully that was easy. If you can do it thrice you can do it a hundred times, or however long it takes to get the job done. Plot Line 5. Station 4 should be at the same place as station 0. Or at least too close to call them different. If there is more that 20 hundredths of a inch between them, try again. If you have already tried again, give it up for a few days. You have blundered, and it should be obvious in hindsight. If it is already a few days later and you are still making the same mistake, perhaps it is hopeless. You can send me back my instruments and instructions, and I'll send you your dollars back. Be sure to enclose the maps which you have tried to draw so that I can improve my instructions. Or just send me copies of your maps and whatever else you have done, and I'll straighten you out. If you have an idea of what went wrong, make a note of it. See the end of this chapter for my address and phone number. Everybody else now knows how to plot a map. The CLOSURE ERROR is the distance on the map between two stations which are supposed to be in the same place. It is a check on the precision, and by implication, the accuracy of your work. Precision is like target shooting and getting all the bullets into the same hole. You have either a good gun rest or a very steady hand. Accuracy is getting them distributed around the bulls eye on the proper target. Your rifle is properly sighted in. The closure error is best thought of as a percentage of the run. The RUN is the distance which you have surveyed around a loop until you used the same station again for the closing station. Just add up all the tape distances. The run for the map of the land description in Table 1 is 865. Measure the distance between station 0 and station 4 on your map. Divide this by 865 and push the % key. If you have no distance between the stations, you have 0% closure error. Congratulations. SIY1.TXT Plot a Map from a Land Description 16 TABLE 2 Line Station Station COMPASS TAPE Comments TO FROM quadrants poles 1 10 10 0 0 Beginning at a stone in Speed's line 2 11 10 S72E 293 3/4 Two white oaks 3 12 11 N37E 123 Corner with Davis & Green 4 13 12 N87W 352 Dogwood in Green's line 5 14 13 S3W 23 The beginning corner again Now look at Table 2. This is the land description of a real parcel of land in Kentucky. The compass is recorded in quadrants and the distance is in poles. This is the common land description notation in Kentucky. You must translate the quadrant notation into the familiar 360 degree notation. The meaning of the quadrant notation is to face the first direction (North or South). Then turn the given number of degrees towards the second direction (East or West). Line 2 has a compass reading of S72E. Set the compass dial so that the pointer points to S, then turn it towards E for 72 degrees. The reading on your compass dial should be 108. Now that you know what you are trying to do, you can take a mathematical shortcut. You can subtract 72 from 180 and get 108. Where did the 180 come from, you ask? Look at your compass. S is 180. N is 360 or 0, whichever is more convenient. E is 90. W is 270. SIY1.TXT Plot a Map from a Land Description 17 To translate quadrants, use the following rules. If the compass direction is a cardinal direction (N, E, S, or W) translate to ([0 or 360], 90, 180, or 270). If a direction is within a quadrant, do the following with the number of degrees in the quadrant: If the quadrant is NE, then add the degrees to 0. If the quadrant is SE, then subtract the degrees from 180. If the quadrant is SW, then add the degrees to 180. If the quadrant is NW, then subtract the degrees from 360. To translate your normal compass direction (azimuth) into the quadrant system, use the following rules: If the direction is a cardinal direction ([360 or 0], 90, 180, or 270), then translate into (N, E, S, or W). If the compass direction is greater than 0 and less than 90, then the degrees are correct and the quadrant is NE. If the compass direction is greater than 90 and less than 180, then subtract the degrees from 180, and the quadrant is SE. If the compass direction is greater than 180 and less than 270, then subtract 180 from the degrees, and the quadrant is SW. If the compass direction is greater than 270 and less than 360, then subtract the degrees from 360, and the quadrant is NW. Play with the compass dial whenever you are in doubt. Believe it or not, this system made a lot of sense in Antiquity, when the arithmetic was done by hand. Today it is an anachronism. It's only use in the present world is to confuse those who would survey it themselves. A pole is the same as a perch, or a rod. 16.5 feet. This one made sense in the days before the invention of the tape measure. But for now, plot at a scale of 100 poles to the inch. Typical Kentucky land corners are identified under the Comments. SIY1.TXT Plot a Map from a Land Description 18 Translate the compass readings and plot a map of this survey. You can plot it on the same graph paper as you used before. When I plotted a map of the data of Table 2, I really couldn't see any closure error. Calculating with a hand calculator, I determined the closure error to be 3.0 poles, or 0.4%. The direction to station 0 from station 4 is 293 degrees. Compare this with the closure error of your plot. Remember, the percent closure error is the map measured distance between the two stations representing the same location on the ground, divided by the run around the surveyed loop, times 100%. You should come out with a closure error of less than 2%. Anything more is blunder. A bit more about blunder and error. Error is a small difference of opinion which sneaks into your measurements. This is due to the unfortunate fact that the real world isn't mathematically perfect. Error is part of this method. So far, you have made errors in setting the declination adjustment, in setting the degrees on your compass dial, in aligning the compass with north on your map, in placing the compass edge so that it goes exactly thru the previous station, in setting the beginning end of the ruler exactly on the station, in guesstimating exactly where some reading such as 293 3/4 is on the ruler, and finally in getting your pencil in exactly the right spot. And then there are manufacturing errors in the compass. Plus a few more I didn't think of. You can never eliminate all the errors. Just realize that they are there, and manage them. Blunders are the *BIG* mistakes. The most common blunder in surveying is to read the wrong end of the compass. You are going just exactly bassackwards from where you think you are going. Blunders are obvious when you notice them. When eliminated, they are gone completely. Except when someone reminds you of the time when you surveyed for half a day before realizing that your compass was always pointing toward your new belt axe! Blunders, by definition, are big enuf to catch and cure. Always be sure that your work has built-in blunder traps. When they are not caught, little blunders become BIG ERRORS. SIY1.TXT Plot a Map from a Land Description 19 TABLE 3 TO FROM COMPASS TAPE COMMENTS 20 20 0 0 21 20 122 127 feet 22 21 8 169 feet 23 22 3 103 feet 24 23 86 211 feet 25 24 92 174 feet 26 25 S15E 12 poles 27 26 S14E 5 rods 7 links 28 27 S86W 7 poles 5 links 29 28 S2E 1 chain 32 links 30 29 S86W 13 rods 13 links 31 30 N4W 6 poles 1.5 links 32 31 N8E 3 rods 33 32 278 245 feet closes on 20? 34 33 237 15 feet closes on 20 Table 3 gives you some more practice in plotting a map. Note that the direction and distance units vary. Translate of all this into degrees and feet. Plot a map from this land description. SIY1.TXT Plot a Map from a Land Description 20 What sort of closure error did you get? What is this in terms of percent closure error? Is this an acceptable closure error? The actual calculated closure error is 0.00%. Station 33 was supposed to be the closing station as I produced these data. The distance for station 34 is my closure error when hand plotting the map. My hand plotting error was 0.8%, which I consider to be excessive. That's why I use a computer. And the computer is easier too. Take another look at your map. The closure error should be quite small. Now look at the boundary of the parcel and think about it. Is it possible to make a blunder and still have a small closure error? Possible, but not probable. You are now ready to plot a map of whatever interests you. You may need to translate the land description into the proper format to plot. Some units of distance which you may encounter are: a pole or a perch or a rod, 16.5 feet; a rope, 20 feet; a chain, 66 feet; a link, [a hundredth chain] 0.66 feet; a furlong, (ten chains) 660 feet; a yard, 3.00 feet; a meter, 3.28 feet; la vara, 2.78 feet (Texas, variable). If your map comes out too tiny, or if it won't fit on the paper, then you will have to change the scale of your map. A square plot containing 10 acres has the length of each side exactly one furlong, or 660 feet. At a scale of 100 feet per inch, the map of that 10 acre square would be 6.6 inches square. This fits nicely on the graph paper. You might want to plot on a few different scales just to see what happens. If you run off the graph paper, you can add another piece to that side. Line up the grid lines. Mark how the two sheets connect, or tape them together. You can obtain a copy of a deed for a parcel of land by visiting your Recorder of Deeds, or whatever title he holds in your county. Just walk into the courthouse and ask for the deeds. You will need help finding what you want, so ask. The deeds are indexed in various ways, depending upon where you are. In Wayne County Kentucky, deeds are indexed alphabetically by date. Really. I told you that you would need help! SIY1.TXT Plot a Map from a Land Description 21 I find the three little rubber map grippers on the compass to be an annoyance. They are meant to keep the compass from slipping on the map paper. They work too well. Just pull them out and stick them onto the compass box with a piece of sticky tape. You might want them again when using the compass with a topo map in the field. If your deed does not give directions and distances, you are out of luck. There is no way to determine where a boundary given simply as "bounded by John Dough's property on the south" is, unless it is stated on John Dough's deed. You will just have to skip drawing a map from the deed. You may prefer to use a separate circular protractor and ruler for plotting. But start with the Silva Ranger. Using the Silva for plotting on paper will teach you how to use it for surveying. For those of you with land in Township & Range territory, see Chapter 6. Copyright (c)1995 by David Perry Beiter If you have any questions, problems, or comments, write or call me. Dave Beiter, CAVE Inc, 1/2 Fast Road, Ritner KY 42639. 606/376-3137. MCI Mail: 635-1762 byter@mcimail.com X.400: c=US;a=MCI;s=BEITER;d=id=6351762 CIS: >MCIMAIL 635-1762 (be sure to include your name in the text)