features or works of man to be shown, the entiredrawing is in black ink. When, as shown in figure10-35, the features other than the survey lines arequite extensive, color printing is used. Survey lines,numbers, lettering, and railroads are printed in black;topographic relief, roads, highways, trails, culture,alkali flats, sandy-bottom draws, and sand dunes areshown in brown; rivers, lakes, streams, and marshesare shown by conventional symbols in blue; andtimbered areas are indicated in green. Where such agreen overprint might obscure other details, thepresence of timber may be indicated in a note (fig.10-35). These several colors are not shown on thereproduction of the plat presented in figure 10-35,although the various features are indicated inappropriate colors on the original map from whichthis figure was reproduced.A property plat plan must contain the following:1. Directional orientation, usually indicated by anorth arrow.2. Bearing and distance of each boundary.3. Corner monuments.4. Names of adjacent owners, inscribed in areas oftheir property shown.5. Departing property lines. A departing propertyline is one that runs from a point on one of theboundaries of the surveyed lot through adjacentproperty. It constitutes a boundary between areasbelonging to two adjacent owners,6. Names of any natural monuments that appear onthe plat (such as the name of a stream), or the characterof any natural monuments (such as “10-inch oak tree”)that have no names.7. Title block, showing name of owner, location ofproperty, name of surveyor, date of survey, scale of plat,and any other relevant data.The preceding items are those that usually appearon any plat. Some land surveyors add some or all ofthe following as well:1. Grid lines or ticks (a grid tick is a marginalsegment of a grid line, the remainder of the line betweenthe marginal ticks being omitted), when determinable.2. On a plat on which grid lines or ticks are shown,comer locations by grid plane coordinates.3. Streams, roads, wooded areas, and other naturalfeatures, whether or not they serve as naturalmonuments.4. Surveyor’s certificate. This is a statement(required by law in many states) in which the surveyormakes a personal affidavit as to the accuracy of thesurvey, A typical certificate might read as follows: I,(surveyor’s name), registered land surveyor, herebycertify that this plat accurately shows property of(owner’s name), as acquired in Deed Book 60, page 75,of the land record of (named) County, State of (name).5. The area of the property.LAND SURVEY PRECISIONMost land surveying of tracts of ordinary size isdone by using transit-tape methods. For a large tract,however (such as a large government reservation),comers might be located by triangulation, or primaryhorizontal control might be by triangulation andsecondary control by supplementary traversing.The precision used for land surveying variesdirectly with the value of the land and also with suchcircumstances as whether or not important structureswill be erected adjacent to the property lines.Obviously, a tract in lower Manhattan, New York(where land may sell for more than
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million peracre), would be surveyed with considerably higherprecision than would a rural tract.Again there are no hard-and-fast rules. However,the prescribed order of precision for surveying theboundaries of a naval station might require thefollowing:1. Plumb bobs used for alignment and fortransferring chained distances to the ground2. Tape leveled by a Locke level3. Tension applied by spring balance4. Temperature correction made5. Angles turned four timesIf you turn angles four times with a 1-minutetransit, you are measuring angles to approximately thenearest 15 seconds. The equivalent precision fordistance measurement would be measurement to thenearest 0.01 foot. Four-time angles might be preciseenough for lines up to 500.00 feet long. For longerlines, a higher angular precision (obtained byrepeating six or eight times) might be advisable.10-36
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