What are topographical plans and also maps?
1. Topographical plans and also maps are illustrations which show the key physical functions on the ground, such together buildings, fences, roads, rivers, lakes and forests, and also the alters in elevation between land forms such as valleys and hills (called vertical relief). You basic these plans and also maps on the details you collection from topographical surveys.
2. Plans space usually large drawings; maps space usually small-scale drawings. Depending upon the range you usage to do the drawing (see section 9.1): it is a plan if the range is bigger than 1 centimeter for 100 m (1 : 10 000), for example 1 cm for 25 m; the is a map if the range is same to or smaller than 1 centimeter for 100 m (1 : 10 000), for example 1 centimeter for 200 m or 1 centimeter for 1000 m.
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Examplean engineering arrangement could show information you require for structure fish-farm functions such together dikes, ponds, canals or outlet structures, at the scale of 1 centimeter for 25 m (1 : 2 500). A topographical map might show a fish-farm website (scale 1 cm for 200 m or 1 : 20 000) or a region of a nation (scale 1 cm for 1 000 m or 1 : 100 000).
3. Plans and maps have two key purposes in fish-farm construction. They aid guide you in selecting a site, to plan the fish-farm, and designing the frameworks that are required for the farm. Plans and maps also guide you as you lay the end marks top top the ground, so that you have the right to follow the arrangement you have actually made of the fish-farm, and build the structures on it correctly.
Starting topographical plans and maps
4. Before you start a topographical survey, girlfriend should shot to get any available topographical plans and maps that the area, even though they may not be precisely the sort of arrangement or map that you need. Basic topographical maps are accessible from governmental organizations which are responsible for geological surveys or land surveys, for example. Nationwide geographical institutes, soil inspection departments and agricultural advancement agencies can also usually administer existing topographical maps. The cadastral room (that calculates land taxes) of her local government may administer local topographical plans.
5. You will often have to do the topographical plans and maps yourself, however. You will certainly base castle on a plan survey (see thing 7) and direct levelling (see chapter 8). In the adhering to sections, you will certainly learn exactly how to: make the plan or map straight in the ar by plane-tabling (see ar 9.2); or do the arrangement or map from the ar measurements videotaped in your notebook (see part 9.3-9.6).6. ~ above topographical plan or maps, girlfriend should constantly look for: the surname of the area or item of floor mapped, and/or the name of the form of project for which it is used; the specific location that the item of land; the surname of the human being or world who make surveys on which the setup or map is based; the date(s) on which the surveys to be made; the direction that magnetic north; the range at i beg your pardon the setup or map was drawn (see section 9.1); the contour interval, if the upright relief is shown (see ar 9.3); a key, or guide, to the symbols offered in the drawing.This details is regularly located in one edge of the map. That is called the legend.
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1. To represent ranges you have measured in the field on a item of paper, you should scale lock down. This means that you must mitigate the size of the distances proportionally according to a scale. The scale expresses the partnership which exists in between the distance shown on a drawing or map and also the actual distance throughout the ground.
Example1 cm on the setup represents 20 m (or 2000 cm) ~ above the ground, or range 1:2000. 1 centimeter on the map represents 100 m ~ above the ground, or scale 1:10000. 1 cm on the map represents 1250 m on the ground, or range 1:125000.
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Note: a ratio with a smaller number is a bigger scale, the is, 1: 500 is a bigger scale 보다 1 : 1000.
Expressing a scale
2. There room three means ofexpressing the scale of a drawing: as a numerical tantamount such together " 1 centimeter = 20 m", which you should read together "1 cm on the plan represents 20 m on the ground"; together a proportion such as " 1: 2 000" i m sorry you should read as " 1 cm on the arrangement represents 2 000 centimeter = 20 m on the ground"; graphically, through a line that is marked off into drawing ranges that exchange mail to convenient units of street on the ground.3. Table 11 offers the number equivalents the the most usual scales, expressed together fractions. Scales for both distances (in metres) and surface areas (in square metres) are shown also.
Choosing a range
4. Basic topographical maps usually have actually scales ranging from 1:50000 come 1:250000. These room small-scale maps. In most countries, 1 :50000 maps are now available. You can use this for basic planning of aquaculture development, including the planning of your fish-farm.
5. To present greater detail, plan are attracted to a larger scale, mirroring individual frameworks or floor areas. The scales most regularly used in plans room 1 :500, 1 :1000, 1 :2000, 1:2500 and 1:5000. In-depth engineering illustrations use scales much larger than 1:500, for example 1 : 100 or 1: 10.
Note: one-of-a-kind rulers, dubbed "Kutsch" scale or reduction scales, do it straightforward to deliver ground distances onto drawings.