Definitions and Concepts for Secondary Cities

Transcript

1. Definitions and Concepts for Secondary Cities Keith C. Clarke UC Santa Barbara Department of Geography
2. What is mapping? • Fiat Features – Toponyms – Buildings – Land use – Places of interest – Government, institutions, parks, schools, hospitals etc. – Cadastre • Visible Geometry – Roads, streets, highways – Power and communications infrastructure, airports – Water features and resources
3. A changing paradigm • Authoritative mapping: Central agency, public or military funding, systematic coverage, standardized products, often closed distribution • Volunteered Geographic Information: Citizen scientists, no funding, ad hoc coverage, bottom- up procedures, online open resources • New mapping technologies: drones, LiDAR, open imagery and software, SFM methods, mobile devices and social media as sensors • Time series now far more common
4. (Almost) Instant 3D Mapping
5. Chiang Mai, Thailand (Population c400,000)
6. What is dynamic mapping? MAPPING • Change in extent • Change in features • Change in class • Change in fiat descriptions AND • Forecasting, Predicting, Understanding these changes • Often requires models and historical data for validation
7. Mapped dynamics
9. What are secondary cities? • Cities dominated by primate cities • Between 500,000 to 3 million inhabitants • Number of SCs increasing rapidly “long tail” • Often unknown outside of their national or regional context, less mapped • Undergoing historic rates of urbanization and growth due to rural-to-urban migration, increased natural growth and international migration • Perhaps least able to deal with urban problems
10. Zipf’s Rank-Size Rule by Nation Exceptions are Primacy
11. Zip within countries 0 5,000,000 10,000,000 15,000,000 20,000,000 25,000,000 Shanghai Beijing Chongqing Guangzhou Shenzhen Tianjin Wuhan Dongguan Hong Kong Foshan Chengdu Nanjing Shenyang Hangzhou Xi'an Harbin Suzhou Qingdao Dalian Zhengzhou 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Population Rank-Size for Chinese Cities 0 500,000 1,000,000 1,500,000 2,000,000 2,500,000 Tashkent Namangan Samarkand Andijan Bukhara Nukus Qarshi Kokand Chirchiq Fergana 1 2 3 4 5 6 7 8 9 10 Population Rank-Size Uzbekistan 1934-2013
12. Why dynamic mapping of secondary cities? • Bulk of future growth in urban extent and population • Often focus of urbanization ills: flooding, water and power supply, waste and sewage, health, poverty, violence, corruption • Local governments often weak and ineffective • Services low, hazards high • Dynamic mapping essential for triage
13. Costs/Benefits of dynamic mapping in SC Examples: • Assess landslide hazard and move settlements • Anticipate traffic congestion and air pollution • Provide sustainable water supply • Respond to emerging infectious diseases • Evaluate inequitable or dysfunctional government boundaries
14. Some Thoughts • Massive unmet need for basic mapping with update: Estes, J., and Mooneyhan, D. W., "Of Maps and Myths", 1994, PE&RS, 517-524 • Need 4D GIS to track revisions and changes • New technologies are an opportunity • VGI in country is an untapped potential (e.g. Dharavi) • Many forecasting models now available and their solutions tractable with HPC and Cloud Computing • How do modeling and planning overlap? • Urban conversion has a centuries time scale, so consequences are long term
15. Thanks Kibera (Soweto) Source: Martin Tairo