What snowy mountains can I see in the west of Longquan in Chengdu?They did this visual analysis diagram

Cover Journalist Tian Zhi Road

About 1300 years ago, when Du Fu lived in Chengdu, he wrote a quatrack of "Window with Xiling Qianqiu Snow". In modernization, as a large city with a population of millions of people, "opening the window to see the snow mountain" is a unique charm of Chengdu. Recently, the Sichuan Second Surveying and Mapping Geographical Information Engineering Institute drawn the analysis map of Longquan Shanxi overlooking Snow Mountain, allowing us to demonstrate why Chengdu can "open the door to see the mountains" from a scientific perspective.

Guanshan record: Longquan Shanxi overlook the king of Shushan Gongga Mountain

The blue part is the visible range of Longquan Shanxi

In 2017, there were 50 records of Guanshan in Chengdu, two of which saw Gongga Mountain, and 22 times saw the Four Girls Mountain Master Peak. Since then, Guanshan records in Chengdu have risen year by year, and reached 70 times in 2020. Thirty of which saw the sister -in -law peak, and Gongga Mountain appeared 8 times. Although the Guanshan record in 2021 has decreased, it is 63 days, but it has successfully broke the record of 5 years in 93 days to see Gongga Mountain and 33 times.

If you stand in Longquan Mountain Net Red Paper -wait for the Fenglai Mountain Top Restaurant to west, there are mountain peaks such as Emei Mountain, Wawu Mountain, Niushi Mountain, Erlang Mountain, and Chengdu's first peak.

As the highest peak in the world's tens of millions of population -level metropolises, there are permanent glaciers and snow all year round at the top of Daxuetang, and it is only about 100 kilometers from the center of Chengdu. It has become the biggest guarantee for Chengdu to see the snowy mountains, and the Xiling Snow Mountain in the southeast foot has already become the snowy back garden of Chengdu people.

From the perspective of the terrain section, when the wind came to the west, the sight passed the wide Chengdu plain, through the rising mountains that rose sharply through the first step and the second stairs, pointing directly at the Daxue pond.

If the visibility can be better, the four Grandma Mountain Sister Peak, known as the "Shushan Mountain" in the northwest, stands in the mountains and stands in the mountains. Tongmengfeng is 150 kilometers away from Longquan Mountain. Even if there is no professional equipment, you can observe it with the naked eye and use your mobile phone to shoot.

When the visibility is the best, you can see the first peak of Sichuan in Longquan Mountain -Gongga Mountain at 7526 meters above sea level, which appears with Gongga Mountain. Snow Mountain above 6000 meters of the Daxue Mountains.

Although the straight line distance between Gongga Mountain and the waiting wind exceeded 250km, the foothills of about 3,000 meters above sea level were still unable to stop the eyes of Gongga.

Niushan

At the same time, the production team also found that when looking at Gongga, the sight passed the Niushan Mountain, which was about 60km from Gongga. Niushan, known as the 360 ​​-degree "China's largest viewing platform", has returned strongly after the development of the mountains that has been experienced for nearly 7 years, bringing tourists a 3666 -meter viewing platform that can be fully developed and can even live. Essence

Standing on the clouds of Niushi Mountain, the Emei Mountains, Mi Mountain, and Wawu Mountain on the east, the Xiling Snow Mountain, Four Girls Mountain, and Jiajinshan on the north; Gongga Mountain, which is only 50 kilometers away from Erlang Mountain and the straight line.

How to see the mountain? Conditioning map combines optical principles to make visual analysis

If you throw the question of "seeing the mountain" to the geographical person, the visual analysis of the terrain will bring many interesting answers.

Digital high -primary model DEM in modern digital maps

The production observation diagram is first selected as the observation and observation point on the digital ground model of Sichuan. Because Chengdu's famous observation point is in Longquan Mountain, everyone chose an observation point called "waiting for the wind". "Everyone is familiar with here, and it is easy to reach the summit. It is suitable as an observation point."

The production team chose the same famous Gongga Mountain as the observation point and formed a "two -point line" with Longquan Mountain. After the formation of this "line" is formed to obtain a terrain section. It is from the ground section to see the ups and downs of the terrain.

How can we mark our "seeing" point after formation? This is the second step, a visual analysis. Visual analysis is based on the principle of "light along the straight line", and determines the range that can be achieved at a certain point of sight on the surface of the three -dimensional terrain, and obtains the visual range of this point.

Based on the reversibility of light, the point can be observed in these areas that can be seen at this point. At the same time, visual analysis also takes into account the impact of earth curvature and atmospheric refraction.

In short, our eyes look at it at a glance. Like the trajectory of light, the high places will block, and the short places will pass directly through.

When marking the vision point, consider the refraction of the atmosphere to light, and calculate the blocking of the earth shape. "Because the earth is not a plane, but an ellipsoida, when the distance is far away, the impact of the earth's curvature should be considered." Ouyang Xu Tong explained.

Why didn't I see so many snow mountains in Chengdu?

Many people think that because of the obstruction and distance of Qianshan, Gongga Mountain, which is more than 7,000 meters above sea level in Chengdu. However, based on visual analysis, it can be seen on the Gongga Mountain on the Longquan Mountain, which is more than 900 meters. "When the distance is 250km, you can see the peaks of 4905 meters above 4905 meters, but there are still about 900 meters of altitude in Longquan Mountain, so the range that can be seen is wider."

As far as Chengdu is concerned, Gongga Mountain is visible in most places theory, but considering the cover of buildings and trees, it is actually invisible.

It is true that the terrain is the fundamental factor that affects whether it is visible, but there are many important factors to decide whether to see the snowy mountains, such as the buildings and trees on the surface of the terrain on the surface of the terrain will block the sight. For the city center, in addition to high -rise buildings or high -rise buildings at the city center, this makes although many snow mountains can be seen from the perspective of the terrain. Or the Liangfeng 垭, Xinjin Shushan, and Danchang of Sancha Lake on Longquan Mountain.

The other point is the meteorological conditions between the observation point to the observation site. Not only must the weather be fine, but also the air is fresh. To this end, Chengdu Meteorological has released the Meteorological Index of Guanxue Mountain. Among them, the "three levels" can be seen to see Snow Mountain, and "level 5" can be seen at the same time.

"This time this picture is also the support of our ideas and data. Combining the actual situation of Chengdu, we can really apply our results to everyone."

(Drawing: Yang Baoqing Ouyang Xu Tong Lu Wenyuan Tang Jinsen)

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