slide visualization design for choropleths in multi scale statistical mapping

VISUALIZATION DESIGN FOR CHOROPLETHS IN MULTISCALE STATISTICAL MAPPING Van Ngoc Truc Phuong, Le Minh Vinh Faculty of Geodesy and Cartography, HCMC University of Natural Resources and Environment OUTLINE • • • • Rationale Theoretical framework and methods Results and discussions Conclusions RATIONALE Modern cartography takes new missions which include building new principles that ensure thoughtful making and effective use of map products from new and innovative technologies Multi-time Multimedia Multi scale maps RATIONALE Same theme but different visualization methods among a predefined scale range Maps on screen (screen maps) Viewed from distance of 80cm Bảnđồ đồtỉtỉ Bản Multi lệ… lệ… scale RATIONALE Multi-scale map Statistical maps (cloropleth maps with census units) created and mined/explored on screen (screen maps) Same theme Different visualization among predefined scale range RATIONALE indicators, administrative unit level Data classification Color scheme What is the smallest zooming to change? How will the data be classified? What will be the graphics transition? RATIONALE How to set scales’ threshold? At each threshold, how data classification and graphics change? Data Classification: how many groups? What methods? How to apply the color ramp/gradient? THEORITICAL FRAMEWORK AND METHODS THEORITICAL FRAMEWORK AND METHODS (1) Rules for level of scale range: defined by readable smallest area units Based upon ability of human eyes to recognize objects: 2,5 mm2 THEORITICAL FRAMEWORK AND METHODS Map Commune Zoom out Map at smaller scale N readable smallest area unit < 2.5 Y district Scale’s threshold Classification change/ graphic transition: administrative unit level province RESULTS AND DISCUSSIONS (1) SCALE RANGE readable smallest area unit PROVINCE level: Bac Ninh District level: District Commune level: Ward 3, District 10 Map PROVINCE level District level Commune level AREA (km2) SCALE 823,710249 4,1593463588 0,1011324536 1/18.000.000 1/1.300.000 1/200.000 Scale 1: 1.300.000 -> 1:18.000.000 1:200.000 -> 1:1.300.000 >1: 200.000 RESULTS AND DISCUSSIONS (2) DATA CLASSIFICATION classification is effected by various factors Of which, value of classes have to satify classification goals: (a) to explore urbanization intensity (b) to explore population distribution RESULTS AND DISCUSSIONS (2) DATA CLASSIFICATION 2a to explore urbanization intensity : criteria based on decree 42/2009/NĐ-CP Urban types Pop Density Administrative level (person/km 2) Province District Commune Đô thị đặc biệt 15.000 x Type 12.000 x 10.000 x Type 10.000 x 8.000 x Type 6.000 x Type Type 4.000 4.000 2.000 x x x RESULTS AND DISCUSSIONS (2) DATA CLASSIFICATION Commune 20.000 Province