OBSTACLES IN ANGULAR SURVEYING. CHAPTER I. Perpendiculars and Parallels. (402) To erect a perpendicular to a line at a given point. 279 (403) To erect a perpendicular to an inaccessible line, at a given point of it 280 (404) To let fall a perpendicular to a line, from a given point. 280 (405) To let fall a perpendicular to a line, from an inaccessible point. 280 (406) To let fall a perpendicular to an inaccessible line from a given point.. 281 (407) To trace a line through a given point parallel to a given line 281 (408) To trace a line through a given point parallel to an inaccessible line.. 281 ARTICLE CHAPTER II. Obstacles to Alinement. A. To prolong a line 282 282 (409) General method 283 PAGE 282 (413) When the line to be pro- B. To interpolate points in a line .... .... 284 284 | (418) By Latitudes and Depart- Obstacles to Measurement. A. When both ends of the line are accessible (421) Previous means (422) By triangulation 287 287 287 | (423) A broken base B. When one end of the line is inaccessible .... C. When both ends of the line are inaccessible.......... 290 (440) CASE 1. When the length and bearing of any one side are wanting. CASE 2. When the length of one side and the bearing of another are wanting 297 When the deficient sides are separated from each other.. 299 299 (444) CASE 3. When the lengths of two sides are wanting.. 300 300 (445) (4.16) When the deficient sides are separated from each other 301 301 447) CASE 4. When the bearings of two sides are wanting.. 302 302 (448) When the deficient sides are separated from each other..... 802 PART XI. LAYING OUT, PARTING OFF, AND DIVIDING UP LAND. E. By a line passing through a given point within the field. (529) By lines running in any given direction 348 (530) By lines starting from an angle .... (531) By lines starting from a point in a side. (535) By lines passing through a point within the triangle 349 349 851 (540) Do. the point being to be found.... 353 (541) Do. (512) By the the point to be equidistant from the angles shortest possible line..... 353 854 Division of Rectangles. (543) By lines parallel to a side.... 354 (551) By lines starting from an angle ... ARTICLB (544) By lines parallel to the bases. (546) By lines starting from points in a side. Division of Quadrilaterals. PAGE Division of Trapezoids. 35 355 356 356 358 358 358 858 859 (554) By lines passing through a point within the figure Division of Polygons. (555) By lines running in any given direction... (558) By lines passing through a point within the figure PART XII. UNITED STATES' PUBLIC LANDS. 360 360 361 361 361 |