Map and compassion recognition and use Read more >>
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The basic marking of the contour map
Contour map is to connect the points with the same surface height into a circle and project it directly to the plane to form a horizontal curve. The loops with different heights will not match, unless the surface shows cliffs or cliffs to make the lines appear too dense and overlapping. The flat and open slopes of the outlet line are quite wide, and its baseline is based on the average sea level of the sea level. There are marking instructions at the bottom of each map to make it convenient for users to use. There are scales, figure numbers, map join tables, legends, and orientation angles.
The scale is the symbol that must be marked on the map. It is the proportional correlation that shows the actual distance between the surface and the distance between the maps. For example, a map with one hundred thousandths shows a centimeter, that is, a map with an actual distance of one kilometer and one ten thousandth of a map. It represents one centimeter, that is, the actual distance is five hundred meters. For the accuracy of maps and actual distances with different scale ratios, the accuracy of the map with small scale is higher. Scale and Actual Distance Conversion Table Map Scale Field Distance (meters) Map Distance (cm) 1:25,0001,00041: 50,0001,00021: 100,0001,0001
The map number is a number that represents the name of the map. Different scales of maps are coded in the respective systems, and it is based on latitude and longitude so that each map can be closely linked.
The azimuth declination angle is the angle that positive north (earth north pole), magnetic north (magnetic needle shows north), and grid north (map indicates north) are deviated from each other. At the same time, the year-by-year magnetic variable value is attached to the figure below. We can use the north arrow to indicate our position and then map the map so we can quickly know where we are and where we are going and where we are going.
The legend is to explain the meaning of various symbols on the map. Generally, the symbols that the climber pays attention to are triangle points, wall collapses, rivers, lakes and slopes.
Contour maps and terrain analysis
First, the type of contour
When we look at the contour map, we will find that there are two types of lines: the thickness and the fineness of the line drawn on the map. This is convenient for users to read and design. The thick line measures the curve and indicates the altitude, and the distance between the curves is 0.2 centimeters. The curve is called the first curve. It is between the meter curves and has the function of facilitating the analysis of the terrain. There are four curves between each two curves. The distance unit between each line is 0.04 cm.
Second, the blind spot of the contour
The higher the scale, the poorer the precision is because the actual distance between the contours is too wide and the terrain in this space cannot be clearly identified and the blind spots appear. Take the map of 50,000th of an example as an example, the distance between each curve is The actual distance is 20 meters (equivalent to the height of the seven-story building).
Third, slope
The slope contour contour map is one of the most easily recognizable features of the terrain. We can understand the slope of each peak by observing the map roughly. For example, the narrower the distance between the curves, the steeper the slope, the wider the curve spacing, the slower the gradient. The uniform spacing of the curves indicates that the section is equal slope, if the spacing above is less than the spacing below, it means that the section is a concave slope, and vice versa. The calculation of the slope gradient of the convex slope is based on the calculation formula of the trigonometric function. The formula: tan-1 (vertical distance ÷ horizontal distance) = angle takes the map of 50,000th of an example as its slope, actual distance and curve spacing. Relationship. (Slope) θ = tan - 1n/m Table 2, slope, slope condition and walking degree Slope slope condition Degree of walking 1° - 5° Gentle hillside driving Easy 5° - 15° Slow hill walking Easy 15° - 25 ° Semi-emphasis slopes can walk 25°～30°hills can climb 35°～45°hills can climb steep slopes can climb 45°～90° cliffs, cliffs must be climbed with the help of equipment.
Draw and read contour maps
When we purchase contour maps, we must clearly see whether or not we completely include the areas where we have scheduled activities. We usually encounter the need to purchase and put together two to four maps. We usually do not bring the original maps to the wild. We (1) take precedence. Copy and re-coordinate the map of the scheduled activity area. (2) Review the map to distinguish the topographic features of the main and branch ridge lines (that is, the lines connecting the two peaks), streams, slopes, cliffs, and cliffs, etc. (3) Use Different colors of fluorescent pens to draw the main ridge lines, streams, and marking the intended route and camping sites, (D) the use of transparent tape to map and activities scheduled travel plan completely adhesive seal, so easy to carry and waterproof.
North Arrow job
The compass is an indispensable tool for hiking. Its basic function is to use the role of the earth's magnetic field to indicate the north position. It must match the map to find the relative position of the ball to understand its position.
At present, there are many kinds of compasses on the market. This article will describe how to use the north arrow orientation method based on the most widely used transparent floor plate for compassion hiking.
North Arrow zero operation
The north arrow homework is a very important front job using the forest compass. Its steps are: First, place the north compass horizontally. Second, the north zero scale outside the ring and the pointer inside the ring indicate the position of the north overlap, so completing the steps is to complete the zero operation of the north needle.
Target azimuth: When measuring the target azimuth, the north of the site must be parallel to the north of the map, and then the red line of the compass should be aligned with the target, read the angle of the target and grid north, and correct the azimuth deviation of the map. The angle is the target azimuth.
Field positioning
The main purpose of using maps and compasses is to understand the relative location and topographic changes between the user and the destination and to display it on the map.
Directional line intersection method
This method uses the known points of the two maps to measure the target azimuth of another map's unknown point, and the extended lines of the two target azimuths must intersect at this unknown point.