两步移动搜索法案例ppt
网络搜索技巧PPT学习课件
20
终极挑战
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课堂小结
一、搜索引擎的分类 1、目录搜索引擎 2、全文搜索引擎 二、常用搜索技巧
1、确定类别，提炼关键词 2、灵活运用各种在线工具 3、用好逻辑符号 4、强制搜索 5、适时转换搜索引擎
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总结语：
网上搜索好比“大海捞针”，但 只要找到正确的方法和技巧，就一定 能事半功倍，希望通过今天的学习能 给今后同学们的生活带来便利！
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搜索技巧3：用好逻辑符号
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体验探究4：
“明年春色倍还人”原诗的上一句是什么？搜索 时加引号和不加引号哪个搜索出来的结果多？
“寄语洛城风日道√” “莫道今年春将尽×”
搜索技巧4：强制搜索
加“ ”（中英文皆可）进行精确查找，在查 找名言警句或专有名词时格外有用。
为了更准确地搜索电影、电视、书籍等信 息，可以加上《 》(书名号)后再搜索。
2
学习目标：
■知识目标：掌握常用的网络搜索技能，充分体 会搜索技巧在查找信息中的重要性、方便性、快 捷性。 ■能力目标：通过搜索技巧的学习，能借助网络 上提供的搜索引擎查找信息；通过分组协作以及 任务驱动的方法，让学生独立完成作业，并能总 结出一定的搜索技巧。 ■情感目标：培养学生独立思考的能力，团结协 作的的精神，以及引导学生健康上网的意识。
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忠告
网络信息浩如烟海，也有许多 虚假、错误的信息，这就要求我们 不仅要学会搜索，更要善于甄别， 树立正确的价值观，做一名合格的 中学生。
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《》后再搜索。
技巧5
不要局限于一个搜索引擎。当搜索不到理想的结果时，试着用另 外的搜索引擎。
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小组合作大显身手
世界上第一台计算机
两步移动搜索法案例课堂
2SFCA Recap
1a. For each supply location j, select all demand locations
k within a travel time range from j (catchment Cj).
1b. Compute the supply to demand ratio within Cj:
Medical Geography: Health Care Accessibility and Implications
Fahui Wang
Fred B. Kniffen Professor of Geography Louisiana State University
June 17, 2010 @ CNU
S1 ? S2 ? ...? Sn ? S
m
? where
k?1
13
Value of optimization
? Emphasizing the equality issue ? Identifying over- and under-capacity
of supply ? Guiding planning and public policy in
? FCA with a radius/box
? FCA with a travel time range
5
From S/D Ratio to FCA
? Simply S/D Ratio ? FCA with a Radius
? Improvements ? Within-unit variation ? Cross-border
1
Contents
? The issue of access ? GIS-based accessibility measures ? Optimization towards equal access ? Application in healthcare access
基于高斯两步移动搜索法的城市公园绿地可达性研究——以石林县城为例
收稿日期:2023-07-14作者简介:张晓娜(1998-),女,硕士研究生,研究方向为风景园林规划与设计。
通讯作者:张继兰(1977-),女,高级工程师,研究方向为风景园林规划与设计。
张晓娜,张懋琳,张继兰(西南林业大学园林园艺学院,云南昆明650224)摘要:城市公园绿地是城市居民日常休闲游憩的主要场所,分析城市公园绿地的空间可达性,可以有效衡量城市公园绿地供给与居民需求的关系,提高城市公园绿地公共服务水平。
高斯两步移动搜索法由于直观、运算简便,且考虑空间距离和公园绿地供给与居民需求关系,被广泛应用于可达性的研究中。
以石林县中心城区公园绿地为研究对象,应用高斯两步移动搜索法,分别从综合、社区、专类、游园不同类型公园设置不同服务半径搜索阈值,分析了公园绿地空间可达性差异。
结果表明:①石林县中心城区公园绿地空间分布不均衡,其分布特征呈现出由中心向外围递减以及中心城区南部可达性总体比北部高的现象;②专类公园绿地的服务盲区比其他类型公园绿地多,且多聚集在中心城区南部。
研究结果可为未来城市绿地规划发展与优化提供建议和科学参考。
关键词:两步移动搜索法;公园绿地;可达性;石林县城中图分类号:T U 986 文献标识码:A文章编号:1674-9944(2023)17-0041-07R e s e a r c ho nA c c e s s i b i l i t y o fU r b a nP a r kG r e e nS pa c eB a s e do nG a u s s i a n T w o -S t e p Mo b i l e S e a r c h M e t h o d —T a k i n g S h i l i nC o u n t y a s a nE x a m pl e Z h a n g X i a o n a ,Z h a n g M a o l i n ,Z h a n g Ji l a n (,,,650224,)A b s t r a c t :U r b a n p a r k g r e e n s p a c e i s t h em a i n p l a c e f o r u r b a n r e s i d e n t s 'd a i l yl e i s u r e a n d r e c r e a t i o n .A n a -l y z i n g t h e s p a t i a l a c c e s s i b i l i t y o f u r b a n p a r k g r e e n s p a c e c a n e f f e c t i v e l y m e a s u r e t h e r e l a t i o n s h i p be t w e e n u r b a n p a r k g r e e ns p a c e s u p p l y a n d r e s i d e n t s 'd e m a n d ,a n d i m p r o v e t h e p u b l i c s e r v i c e l e v e l of u r b a n p a r kg r e e n s p a c e .Th eG a u s si a n t w o -s t e p m o b i l e s e a r c hm e t h o d i sw i d e l y u s e d i n t h e s t u d y o f a c c e s s i b i l i t y be -c a u s e i t i s i n t u i t i v e ,e a s y t o c a l c u l a t e ,a n d c o n s i d e r s t h e s p a t i a l d i s t a n c e a n d t h e r e l a t i o n s h i p b e t w e e n t h e s u p p l y of p a r kg r e e n s p a c e a n d th en e e d so f r e si d e n t s .T a k i n g t h e p a r k g r e e ns pa c e i n t h e c e n t r a l u rb a n a r e a o f S h i l i nC o u n t y a s t h er e s e a rc ho b j e c t ,t h i s p a p e ra p p l i e s t h eG a u s s i a nt w o-s t e p mo b i l es e a r c h m e t h o d ,s e t s d i f f e r e n t s e r v i c e r a d i u s s e a r c ht h r e s h o l d s f o rd i f f e r e n t t y p e so f p a r k s ,s u c ha s c o m pr e h e n -s i v e ,c o m m u n i t y ,s p e c i a l ,a n d r e c r e a t i o n a l p a r k s ,a n d a n a l y z e s t h e d i f f e r e n c e s i n t h e a c c e s s i b i l i t y of p a r kg r e e ns p a c e s .Th e r e s u l t s s h o wt h a t :①T h e s p a ti a l d i s t r i b u t i o no f p a r k g r e e n s p a c e i n t h e c e n t r a l u r b a n a r e a o fS h i l i nC o u n t y i su n e v e n ,a n di t sd i s t r i b u t i o nc h a r a c t e r i s t i c ss h o w a p h e n o m e n o no fd e c r e a s i n gf r o mt h e c e n t e r t o t h e p e r i p h e r y a n d t h e a c c e s s i b i l i t y of t h e s o u t h e r n p a r t o f t h e c e n t r a l u r b a n a r e a i sg e n -e r a l l yhi g h e r t h a n t h a t i n t h en o r t h e r n p a r t ;②T h e s e r v i c e b l i n d a r e a o f s p e c i a l p a r k g r e e n s p a c e i sm o r e t h a no t h e r t y p e s o f p a r k g r e e n s p a c e ,a n dm o s t o f t h e ma r e g a t h e r e d i n t h e s o u t ho f t h e c e n t r a l c i t y .T h e r e s e a r c h r e s u l t s c a n p r o v i d e s u g g e s t i o n s a n d s c i e n t i f i c r e f e r e n c e s f o r f u t u r e u r b a n g r e e n s p a c e p l a n n i n g de -14v e l o p m e n t a n do p t i m i z a t i o n.K e y w o r d s:t w o-s t e p m o b i l e s e a r c hm e t h o d;p a r k g r e e ns p a c e;a c c e s s i b i l i t y;S h i l i nC o u n t y1 引言随着我国城市化的不断加快,城市空间迅速扩张和人口高速集聚,城市公园绿地空间增长需求与资源约束趋紧、供应不足与空间不匹配等问题日益凸显;与此同时,居民对健康、休闲的需求与日俱增,对城市生活品质和环境质量更为关注,对公园绿地的建设提出更高的要求[1-2]。
成都市青羊区公园绿地空间可达性分析——基于高斯两步移动搜索法
城市公园绿地作为建成环境的重要组成部分，对于人的身体和心理健康有着重要的作用，同时在改善生态环境，提升城市形象等方面都有积极影响。
成都作为公园城市建设示范城市，在《成都市“十四五”公园城市建设发展规划》中提出加快构建多层次全域公园体系，实现“300米见绿、500米见园”。
而可达性作为评价公共服务设施布局合理性的有效手段[1]，能够衡量居民获得公园绿地的服务机会是否公平，同时可以有效评价城市公园绿地配置是否合理。
可达性是由Hasen [2]在1959年提出的，是评估需求方获取供给方所有潜在资源的难易程度的指标。
目前越来越多的学者将可达性运用在公园绿地分布的研究中，常见的度量方法有最近邻距离法[3]、网络分析法[4]、引力模型 [5]、累计机会法[6]，以及两步移动搜索法[7]等，其中最近邻距离法将采用欧氏距离或者网络距离来计算居民到公园绿地点的距离，忽视了绿地本身的质量以及对居民的吸引力；网络分析法主要通过路径与道路拟合来计算可达性，但还是存在一定局限性；引力模型虽然从供给和需求端进行考虑，但是在模型的参数定义上还是存在一定主观性；而两步移动搜索法不仅具有引力模型的优点，并且数据较易获取，方便计算，近年来得到了许多学者的关注与应用，已经成为目前研究公园绿地可达性的主流方法。
从需求点数据来源来看，选择较小的研究单元，可以有效反映区域内公园绿地可达性的差异。
因此，目前许多的研究开始采用人为处理过的规则图形，例如渔网[8]和蜂窝网[9]来进行需求点的模拟。
从道路通行数据来看，摘要 随着健康生活的理念深入人心，人们对公园绿地的数量及品质提出了更高的要求，而可达性可以有效评价公园绿地设施布局是否合理。
本研究以成都市青羊区为例，利用两步移动搜索法对青羊区公园绿地可达性进行分析，并结合可达性冷热点分析进一步探究了青羊区公园绿地分布的合理性。
结果显示：青羊区大部分区域可达性较低，空间差异化较大，整体呈现可达性水平由南部草堂街道向两边逐渐降低的格局，造成可达性不均衡的主要原因是人口需求与绿地供给水平的不匹配。
两步移动搜索法案例(课堂PPT)
12
A Quadratic Programming Approach
min
mn
(
S
j
பைடு நூலகம்
d
ij
a)2
V i1 j1
j
Subject to
6
2-step floating catchment area: 2SFCA
Scale availability at each supply location
Sum up accessible supplies around each demand location
7
2SFCA Recap
Distance Road network Transportation means
4
Primitive measures
Distance (time) from supply Simply potential model
Ai j S jdij
Supply-demand ratio within an area FCA with a radius/box FCA with a travel time range
S1 S2 ... Sn S
m
where Vj
Dk
d
kj
k 1
13
Value of optimization
Emphasizing the equality issue Identifying over- and under-capacity
of supply Guiding planning and public policy in
两步移动搜索法案例知识分享
Optimization
Towards equal accessibility Formulated as a planning problem minimizing accessibility gaps among
2-step floating catchment area: 2SFCA
Scale availability at each supply location
Sum up accessible supplies around each demand location
2SFCA Recap
1a. For each supply location j, select all demand locations
jZi
kC j
Generalizing “distance decay”
as a continuous function
a power or exponential function a Gaussian function
as a discrete variable
dichotomous as in 2SFCA multiple as in E2SFCA
closing the gap
Application in Healthcare Access: HPSA designation
U.S. ranks behind in health performance
deep disparities in access to care and health outcomes
Concluding comments
两步移动搜索法案例PPT课件
Nonspatial
Who you are
Social justice and public policy
3
Measurement
How scarce are the services?
Supply vs. Demand (ratio)
How far are demands from supplies?
Rj S j / Pk kC j
2a. For each demand location i, search all supply
locations j within the travel time range from i
(catchment Zi). 2b. Sum up the supply to demand ratios at these supply
S1 S2 ... Sn S
m
where Vj
Dk
d
kj
k 1
13
Value of optimization
Emphasizing the equality issue Identifying over- and under-capacity
of supply Guiding planning and public policy in
locations:
Ai Rj (S j / Pk )
jZi
jZi
kC j
8
Generalizing “distance decay”
as a continuous function
a power or exponential function a Gaussian function
两步移动搜索法案例 PPT课件
Miles
0 12.5 25
50
75
High Health Care Need Scores (Factor 3)
±
High Health Care Need Scores (Factor 3)
Legend
FACTOR3
-7.376800 - -1.760400 -1.760399 - -0.702300 -0.702299 - 0.023100 0.023101 - 0.715200 0.715201 - 1.697400 1.697401 - 5.786100 County Boundary
Concluding comments
Access Matters!
Convenience of access to activities
job, school, healthcare, park, public service, shopping …
Access defines “location” Spatial
closing the gap
Application in Healthcare Access: HPSA designation
U.S. ranks behind in health performance
deep disparities in access to care and health outcomes
Miles
0 12.5 25
50
75
Socioeconomic Disadvantage Scores (Factor 1)
±
Socioeconomic Disadvantage Scores (Factor 1)
Legend
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-
Access Matters!
Convenience of access to activities
job, school, healthcare, park, public service, shopping …
Access defines “location” Spatial
Where you are
Nonspatial
Who you are
Social justice and public policy
-
Measurement
How scarce are the services?
Supply vs. Demand (ratio)
How far are demands from supplies?
demand locations by adjusting the amounts of supplies at given supply locations.
-
A Quadratic Programming Approach
m n
min (
Sjdij
a)2
V i1 j1
j
m
where Vj Dkdkj k1
-
Validation
Modeling actual supply-demand interactions
Individual travel behavior Aggregated travel pattern
-
Optimization
Towards equal accessibility Formulated as a planning problem minimizing accessibility gaps among
Distance Road network Transportation means
-
Primitive measures
Distance (time) from supply Simply potential model
Ai jSjdij
Supply-demand ratio within an area FCA with a radius/box FCA with a travel time range
Subject to
S 1 S 2 . S n . S .
-
Value of optimization
Emphasizing the equality issue Identifying over- and under-capacity
of supply Guiding planning and public policy in
as a discrete variable
dichotomous as in 2SFCA multiple as in E2SFCA
a hybrid approach
a kernel density function a three-zone approach
-
Generalizing “distance decay”
closቤተ መጻሕፍቲ ባይዱng the gap
-
Application in Healthcare Access: HPSA designation
U.S. ranks behind in health performance
1a. For each supply location j, select all demand locations
k within a travel time range from j (catchment Cj).
1b. Compute the supply to demand ratio within Cj:
locations:
Ai Rj (Sj/ P k)
j Zi
j Zi
k Cj
-
Generalizing “distance decay”
as a continuous function
a power or exponential function a Gaussian function
Rj Sj / Pk kCj
2a. For each demand location i, search all supply
locations j within the travel time range from i
(catchment Zi).
2b. Sum up the supply to demand ratios at these supply
-
Contents
The issue of access GIS-based accessibility measures Optimization towards equal access Application in healthcare access
PHSA designation and late-stage cancer
-
From S/D Ratio to FCA
Simply S/D Ratio FCA with a Radius
Improvements Within-unit variation Cross-border
Limitations Straight-line S-D beyond radius
Medical Geography: Health Care Accessibility and Implications
Fahui Wang
Fred B. Kniffen Professor of Geography Louisiana State University
June 17, 2010 @ CNU
-
2-step floating catchment area: 2SFCA
Scale availability at each supply location
Sum up accessible supplies around each demand location
-
2SFCA Recap