DEVELOPMENT AND IMPLEMENTATION OF A NEW WEB MAPPING SYSTEM ARCHITECTURE FOR ARCTIC REGION

Transcription

1 GEOIDE SSII#109 DEVELOPMENT AND IMPLEMENTATION OF A NEW WEB MAPPING SYSTEM ARCHITECTURE FOR ARCTIC REGION Presenter: Fanny Tsai hftsai@ucalgary.ca Supervisor: Dr. Steve Liang steve.liang@ucalgary.ca Date: Oct. 26, 2012 GeoSensor Web Lab Department of Geomatics Engineering Schulich School of Engineering University of Calgary 1

2 Outline Introduction of our web mapping system System requirements System architecture Implementation Use cases Demonstration Future works Implementation of YorkU s projection Refine basic functions Intelligent map projection selection system 2

3 System Requirements Objective: A polar-region-focused web mapping system to store and present pre-rendered geographic information. Can be accessed by most web browsers. Be able to switch between different projections easily. Be able to rotate the map. Short response time 3

4 System Architecture Client Server Data Tile Maker 4

5 Implementation Client Web page: JavaScript Web mapping framework: Bing Maps API HTML styling: Twitter Bootstrap Server Web server: Java Servlet / Apache Tomcat 5

6 Implementation cont d Map Mercator projection Re-project to polar projections (ArcGIS) Custom maps: polar-centered projections - Lambert azimuthal equal area - Azimuthal equidistant - Orthographic - Stereographic - Gnomonic For each projection, rotate 30 degrees each time to generate 12 maps with different rotation (Matlab) Cut each projection/rotation map into tiles by following Bing Maps tile structure (Matlab) Map Tiles 6

7 Mercator ArcGIS Polar Projection (a) Azimuthal Equidistant (b) Lambert Azimuthal Equal Area 7

8 Bing Maps Tile System Map is composed by tiles of 256*256 pixels each. To optimize the indexing and storage of tiles, the twodimensional tile XY coordinates are combined into one-dimensional strings called quadtree keys, or quadkeys for short. Each index contains 2 information: particular level of detail parent index 8

9 Custom Tile Hierarchical Directory Structure Projection 9

10 Request / Response Client creates request for server request request Start Get view center of the viewport Get required tiles Get BBOX of the viewport tiles tiles Quadkey Projection Rotation 10

11 Use Cases Browsing Switch to different projection Rotate map Challenge: re-calculate view center Upload shapefile and display 11

12 Coordinate System Every calculation was done based on image coordinate system (pixel) 12

13 Use Case - Switching Between Different Projections 13

14 (Lat, Long) (Easting1, Northing1) (Easting3, Northing3) Projection1 (Easting2, Northing2) Projection2 Projection3 14

15 Solution 15

16 Why Is Rotation Important? Where s north? 16

17 17

18 Rotation Rotate 30 degrees 18

19 Use Case - Rotation 19

20 Calculation based on image coordinate (pixel) Get North Pole s pixel coordinate in current view (the origin of coordinate is current view center) Set North Pole as the origin of pixel coordinate system Calculate new view center x' = x cos(rotation) - y sin(rotation) y' = x sin(rotation) + y cos(rotation) Solution 20

21 Client Server Shapefile Shapefile USER Parse shapefile Data String (JSON) Create JSON string Create shapefile object (Layer) Display Reproject Rotate 21

22 Necessary Files For Our System Main file: XXX.shp Index file: XXX.shx dbase table: XXX.dbf Projection file: XXX.prj Shapefile has to be packed as a ZIP file and without folders. The uploaded file format zip file WGS84 projection 22

23 DEMONSTRATION URL: 23

24 Summary We proposed an architecture which serves a good platform for public/organizations that need to share/display their polar region data. 24

25 Future Works Implementation of YorkU s projections (in progress) Refine basic functions Layer manager Handle attribute data of uploaded shapefile Adopt input data with other projections Intelligent map projection selection system 25

26 Intelligent Map Projection Selection System Problem statement: There are many map projections but it is difficult for amateur to choose the most suitable one regarding scale, geometry, application, etc.. Objective To provide a knowledge-based recommendation system for map projection selection. 26

27 Questions and Discussions This research is sponsored by GEOIDE SSII#109 and TecTerra 27