Contents Use of a Database System (SQL Server) as a GIS to store and analyze geographic data Use of Web Mapping Service (Google Maps) to display geogr

Transcription

1 DISPLAY OF GEOGRAPHIC TRANSPORTATION DATA STORED AND INTEGRATED IN A SQL SERVER DATABASE Presenter: Francisco J. Torres, P.E. North Central Texas Council of Governments 23rd Annual GIS-T Symposium April 12, 2010

2 Contents Use of a Database System (SQL Server) as a GIS to store and analyze geographic data Use of Web Mapping Service (Google Maps) to display geographic data over the internet Interaction between SQL Server and Google Maps Examples of displaying and editing geographic data over the internet 2

3 Advantages of a Database Management System Multi-user user simultaneous update of files that favors consistency of datasets Embedded security features Natural system to track changes made by users Extensive tools available to display and update datasets over the internet Implicit system to enforce relations within associated datasets 3

4 Database Approach 4

5 Use of SQL Server 2008 Includes all features available in a typical database system New spatial features available Creation, manipulation and analysis of spatial data is available Editing tools of geographic features, similar to those of a GIS are not yet available 5

6 Spatial SQL Server 2008 Based on the Geography and Geometry data types Analysis and modification of data using T-SQL commands Window to visualize results of Select commands of geographic types The Basic geographic entities are Point, Curve and Surface 6

7 SQL Server Spatial Data Objects Geometry Surface Curve Point Geometry Collection Polygon Line String Multi-Surface Multi-Curve Multi-Point Multi- Polygon Multi-Line String 7

8 Querying Spatial Data 8

9 Web Mapping Service Provider (Google Maps) Datasets compiled by the source, such as roads and aerials, are readily available Tools, such as address locator or geocoder, are also available Users of internet are familiar with basic commands for zooming or panning 9

10 Google Maps Application Programming Interface (API) Allows embedding Google Maps in own web pages with JavaScript Provides a number of utilities for manipulating maps Is a free service, available for any web site that is free to consumers All programming features are available as objects and functions 10

11 Simpler Approach: Displaying a Static KML file Web Brows er Web Server Google Maps Server ADVANTAGES A KML file can be created in advance The file is loaded once in the Web Server DISADVANTAGES The system becomes unstable for more than 500 point features in the KML file The restrictions on number of points applies also to points of lines and polygons 11

12 Solution for Large Size Datasets 1. Programmatically apply filters to define a subset of points that fit into an area 2. Set a maximum number of features that can be displayed at once 12

13 Process to Query and Display Data Web Server SQL Server Client HTML Web Browser JavaScript VBScript Procedures Google Maps Server Map API 13

14 Dynamic Creation of KML File SQL Server Web Server COORDINATES SELECTED FEATURES Web Brows er Create KML File Google Maps Server 14

15 Display of Traffic Counts 15

16 Traffic Control Devices 16

17 Signalized Intersections 17

18 At-Grade Railroad Crossings 18

19 All-Way Stop Signs 19

20 High Occupancy Vehicle (HOV) lanes 20

21 Edit Geographic Entities on the Internet 21

22 Summary System suitable to keep inventories of infrastructure Represents an easy way to display geographic datasets on the internet Provides a tool to maintain data associated to geographic entities Editing tools are easy to implement for point features 22

23 Next Applications Considered Historic transit ridership by route and stop/station Automatic upload of traffic counts by local agencies Display of travel forecast network attributes Representation of travel times for selected corridors 23

24 Questions? Thanks! Contact: Francisco J. Torres (817)