Importance of view

London is no doubt my favorite city.

There is s a very carefully written building height restriction based on view: London View Management Framework. Probably should also called "no one shall block my view to St Paul's Cathedral".

It protected 27 strategic views in London, including panorama, leaner views, along  Thames river view and town views not disturbed by new construction. 

The code is highly detailed, including how to calculate the height, the width of the view, and the height of the eye level. It even consider the astronomical refraction. A view includes foreground, middleground and background. 

The red zone in the diagram defines highly restriction area. Orange and yellow zone are areas negotiable. Counting from the drum of the St. Paul to the view point, there's shouldn't be any interruption. The foreground and background are easily understandable. The background are also protected for artistic reason. 

Among these protected views, there's a extensive long view. I think too poetic to miss it. 

It is from King Henry VIII's mound to the St Paul's cathedral. It preserved from 18th century. It is 15.6km from the mound to the cathedral, equals Beijing's East 5th ring to Tian'an men square, or Shanghai's  Pearl tower to Hongqiao airport, or Mahattan's 160th street to the South seaport. 

The cathedral is so tiny with such a long distance. The view also framed by the surrounded branches, like peaking from a key hole. Every year these branches are trimmed to assure the view as well. 

Notes:

London rarely has high-rise buildings. Before 1948, it was restricted because fire fighting ladders' length and for structure safty. Sine 1930, building code were written to protect Thames south bank to see the St.Paul cathedral and limits the building heights to 24.4m. Until 1970, St.Paul cathedral was still the tallest building in the city (111.7m). Since 1991, LVMF started, a few existing buildings broke the code were demolished.

This low density control also becomes a problem of urban development. The city can only grows outward. In 2007 many views' range has shrinked at least half and increased 10% in 2012. 

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我最喜欢的城市是伦敦无二。（可能还有京都。。）伦敦有个十分细心制定的用视野为标准的建筑高度规范 ：London view management framework. 大概可以叫“全世界都不能挡我看大教堂”。规范保护27个重要城市视野（London's strategic views），包括全景，线性视线，泰晤士河边的视野，以及小镇视野不受新建干扰。规定很细致，从怎么计算高度，视野宽度，和视点高度都十分明确，甚至考虑了大气折射对视野的影响。视野分前景，中景和远景。这张图解释视角。

红色三角是从视点到标志建筑的绝对不能碰的区域，期间不能新建超过影响视线高度的线。其他橘黄和淡黄色是可以再评估的地方。高度以大教堂的drum开始 （52.1）米 为标准，从视点向这个高度画线，中间的新建不能超过这个高度。前景中景很好理解，建高了会挡视线。如果新建在视野的远景范围里面也会重新审议。有的房子因为建在背景里面妨碍美观也被制止了，这张图就是例子，后面是建议的图片。


一般情况下是这样：里面有对视线区域的详细定义
 

其中有个超长的视线，我觉得太诗意了。
这个从king Henry VIII's mound看圣保罗大教堂的视线从18世纪就保留至今。
从墓地到大教堂距离是15.6km。15.6km, 可以参考北京东五环到天安门的距离，上海东方明珠到虹桥机场，曼哈顿最南边的港口到160街。

这么远的距离要保证能看到大教堂。其实能看到的很教堂已经很小，大教堂被近处的树枝包围，像从钥匙孔窥探一样。这些树枝每年还要修剪来保证这个景观。




背景：

伦敦建筑都不高，在1948年的规划以前是因为消防车梯子长度限制和保障建筑稳固。从1930年的建筑法案开始有意识的保护从泰晤士南岸观看圣保罗大教堂等的视野，并要求建筑高度上限是80ft (24.4m)。 到1970年，圣保罗大教堂仍然是全市最高的建筑(111.7m)。 1991开始lvmf规定实施后，视野中有几个超过高度的高楼，后来也因为不合规定拆除了。

现在这样的低密度控制也成了城市发展的问题，城市只能向不断周边发展。2007年视线宽度很多减少了一半。2012年又恢复了10%。这几年伦敦也有不少高楼，还在建的the shard (310m / 1100ft)将成为欧盟第一高楼。

我喜欢伦敦一部分原因也是因为低密度和窄街道，可以步行，可以骑车。一个城市这么努力保护的可能好多游客都不知道的景观，真是感动的眼角湿润！

1930 building act
http://www.legislation.gov.uk/ukla/1930/158/contents/enacted
London view management framework
http://www.london.gov.uk/priorities/planning/supplementary-planning-guidance/view-management