Tài liệu 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 do 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 THEORITICAL FRAMEWORK AND METHODS Map at commune level Zoom out Commune Map at smaller scale readable smallest area unit < 2.5 N Scale’s threshold Y Classification change/ graphic transition: move to higher administrative unit level N N Cấp TK = Tỉnh/TP Y Bản đồ cấp Tỉnh/ TP district province THEORITICAL FRAMEWORK AND METHODS (2) Rules for data classification Conventional map: best classification methods ensure that all thresholds have to make sense; all group members concentrate around representative values (if any) and have appropriate GVF, GADF… Multiscale: classification satisfy traditional rules and they also need to be consistent throughout the scale ranges -> the classes for the less detailed mapping level should be translated to more detailed levels and add new more classes. THEORITICAL FRAMEWORK AND METHODS (3) Rules for color scheme Conventional map: color ramp need to present both hierarchical order and have to corresponding to value of each group (Use histogram) Multiscale map: guarantee consistency in color ramp among classes of different administrative unit levels RESULTS AND DISCUSSIONS Case study: Layers of : RESULTS AND DISCUSSIONS Case study: Layers of : RESULTS AND DISCUSSIONS Case study: Layers of : RESULTS AND DISCUSSIONS (1) SCALE RANGE readable smallest area unit PROVINCE level: Bac Ninh District level: District 4 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 1 12.000 x 10.000 x Type 2 10.000 x 8.000 x Type 3 6.000 x Type 4 Type 5 4.000 4.000 2.000 x x x RESULTS AND DISCUSSIONS (2) DATA CLASSIFICATION Commune <2.000 2.000-4.000 4.000-6.000 6.000-8.000 8.000-10.000 District <2.000 2.000-4.000 4.000-6.000 6.000 -8.000 8.000 - 10.000 10.000-12.000 12.000-15.000 15.000-20.000 10.000-12.000 12.000-15.000 >15000 >20.000 Province <2000 2.000-4.000