Traverse Tables/Adjusting Bearings and Distances

Figure 7-15.—Sample pages from traverse table. in departure. The corrections, however, are opposite in sign to the error of closure. distances of from 1 to 100 feet. For a particular traverse line, you determine the latitudes and departures by breaking down the distance, moving decimal points, and adding up results as in the following example: Traverse Tables/Adjusting Bearings and Distances Suppose you want to determine the latitude and departure for a traverse line 725.32 feet long, bearing N15°30'E. To get the latitude, do it as follows. In the latitude column under 15 1/2°, lookup the latitude for 70 feet. You read 67.45 feet. If the latitude for 70 feet is 67.45 feet, the latitude for 700 feet is 674.50 feet. Note this in your notes. In computing latitudes and departures, your arithmetical calculations can be greatly expedited by the use of a traverse table, in which latitudes and departures for any bearing and distance can be determined mostly by looking for them in the table. Figure 7-15 shows sample pages from a table that gives angle-of-bearing values to the nearest quarter- degree (15'). More precise tables give angular values to the nearest 01'. Next, you look up the latitude for 25 feet under the same 15 1/2° latitude column, which is 24.09 feet. The latitude for 725 feet, then, is 674.50+ 24.09= 698.59 feet. Under each of the bearing values at the head of the page, a double column gives latitudes and departures for 7-12