Using Geographic Information, Multimedia and Landscape Modeling as Integrated Visualization Tools in Developing Highway Corridor Management Plans

Transcription

1 Using Geographic Information, Multimedia and Landscape Modeling as Integrated Visualization Tools in Developing Highway Corridor Management Plans Christopher J. SEEGER 1 Introduction One of the difficulties when working with corridor projects is that they tend to cover great distances and can include thousands of resources and features that need to be accounted for in the corridor plan. Documenting a corridor often requires that a large expenditure of time and project funds be spent on numerous trips into the field to collect and verify data. Safety is also an issue with transportation corridor projects due to the lack of safe roadside parking, especially along Interstate corridors. One solution that encourages safety while reducing the need to traverse the corridor is to utilize digital audio, video, photography and other multimedia tools to capture information about the corridor for review back in the project studio. When integrated with geographic data, this multimedia information can be a very beneficial resource both during and after the planning and design process. This paper will present the technique used to build a custom designed integrated geographic, multimedia, and visualization system as part of the Iowa State University, Department of Landscape Architecture project Maintaining The Image Of Iowa Beyond The Right-Of-Way: A Corridor Management Plan For Significant Natural, Cultural And Visual Adjacencies To Interstate Project Background This Iowa Department of Transportation funded project involved developing a management plan for the Iowa portion of the Interstate 80 corridor. This corridor management plan documents the cultural, historic, and agrarian features that contribute to the internationally recognized nostalgic Image of Iowa. Additionally, the plan identifies methods for the preservation of these features while encouraging economic growth, environmental conservation, and transportation safety. The 330 road miles and approximately 2,000 square miles of land (3 mile buffer either side of the roadway) that make up the corridor as well as the number of resources mapped (4,000 farms, 62 municipal entities and 17 county zoning jurisdictions) necessitated the need for a Geographic Information System (GIS). ArcView GIS was used to both organize the thematic data and to model various spatial relationships between the corridor features. The hyperlink functions within ArcView provided an efficient method to connect GPS located digital photographs of corridor resources with their geographic attributes. Using the hyperlink function, various types of media including text documents, digital photos, and simple video files could be hot linked

2 2 C. J. Seeger to mapped features (PRATT, 2001). However, ArcView lacked the flexibility to easily incorporate the following desired functions. Display multiple synchronized video streams (left, center and right view) Identification of video cue points (i.e. chapters/tags) Support for multi-user/platform environments Design of customized user interface and controls (such as slider bars) Integration with Internet driven media Stand alone data viewer A true dedicated multimedia-authoring environment was needed to design a data viewer that could integrate these six functions with ArcView shapefiles and raster data. 2 Technology Review 2.1 Multimedia Authoring Environments There are several multimedia-authoring applications on the market today; among the most common are Macromedia Director and Macromedia Flash. Both applications utilize a timeline cell animation scheme to organize how, when and where data appears on the screen. Timelines can be controlled in Flash through a scripting language called ActionScripting while Director uses Lingo as its programming language. ActionScript is very similar to JavaScript as it follows the ECMA-262 Standard, the specification written by the European Computer Manufacturers Association that was derived from JavaScript (FRANKLIN, 2002). Lingo is an object-oriented language similar to C, Pascal or Java (GROSS and ROBERTS, 2000). ActionScript and Lingo can be invoked when the playback head enters a frame, a graphic element is selected, a key is pressed or a function is called from another script. The primary difference between the two authoring systems is the type of media supported. Both programs can support raster, video, audio and vector data as embedded, linked or Internet sourced files. However, the main strength of Flash is its ability to import vector data and produce small file size animations. Flash supports Adobe Illustrator, AutoCAD DXF, and the EPS file formats. Director provides a more robust raster rendering engine and provides better support for high data rate video. For Web integration Flash has the advantage, exporting authored animations in the compressed Shockwave Flash (SWF) file format. Director can import and interact with SWF files through bi-directional communication between ActionScript and Lingo. Both programs can produce cross platform stand-alone runtime programs called projectors. In addition to the main timeline, Flash allows additional timelines to be nested inside of the main timeline. These nested timelines are referred to as "movie clips" (MC) and are treated as any other graphic element except that they can contain complex scripting and be controlled by scripts from other timelines. Movie clips can also be dynamically created and contain SWF files located on a CD-ROM or the Internet.

3 Geographic Information, Multimedia and Landscape Modeling - Integrated Visualization Tools File Formats Various types of files and file formats are utilized to display the maps, photographs, and video animations that are part of this project. The native vector format of ArcView is the shapefile; unfortunately this format is not directly supported by either of the authoring applications. ArcView is capable of exporting DXF, EPS and Illustrator formatted files, however these formats do not contain the geographic information necessary to register the map files once they are imported into the authoring environment. Adobe s Scalable Vector Graphics (SVG) file format and Web development language is based on XML and provides data driven interactive graphics for Web applications. Through the use of SVGMapper, the SVG format can be exported from ArcView GIS and used with Web mapping applications, however the format is not fully supported by Director (PRELOZNIK, 2002). Video files can be very large unless they are compressed using a compressiondecompression (CODEC) algorithm. Several CODECs are available and the selection of the appropriate CODEC depends on if the video content is a graphic animation, talking head, landscape scenery or action footage. CODECs offer variability in data rate, display quality and file size. The Sorenson Video CODEC provides good compression with acceptable image quality. The main drawback of this CODEC is that it requires a fairly fast computer to decompress the video and display it at an acceptable quality (DISCREET, 2002). 3 Methods & Procedures 3.1 Required Viewer Functionality The two most critical functions of the viewer included the ability to hot-link video and photography to mapped data and the capability to post and review notes and comments about each corridor segment. Linking the map data to one single video stream is a straightforward process, however, the project required that all three camera views down the roadway (left, center and right) be synchronized and play at the same time. The comment window also had to be synchronized with the video segment selected. One additional required function of the viewer was with the map data itself. The size of the computer limited the scale at which the maps could be displayed, therefore it was necessary to include zoom and pan functions into the map interface. User controlled layer stacking and data visibility was also a desired feature. 3.2 Viewer Components The targeted monitor size and resolution for the viewer was 11x17 and 1024x768 respectfully. This size provided adequate space for the six major components of the interface; videos, video controller, mile marker selector, comment window, media resource bin, and map interface (Fig. 1).

4 4 C. J. Seeger Figure 1. Example screenshot of component layout of prototype viewer. 3.3 Map Design & Implementation The first step in creating the viewer interface was to import the base map information from ArcView shapefiles into Flash. As discussed, ArcView does not include an option for exporting files in the SWF file format. The solution to this problem was MAPublisher for Illustrator from Avenza Software Inc. This program provided a simple method for registering the shapefile from ArcView and converting the geometry into the SWF format. The map base, an outline of the state, was the only data layer that was built directly into the map interface, the other map layers were loaded separately as external SWF files. Inclusion of the map base in the interface layout was required so that a reference point could be established and used to locate external SWF map layers as they were loaded into the program by the user. In addition to the base map, the user menu interface was designed in Illustrator and exported as an EPS file to Flash. Once in Flash, the base data was converted into a movie clip named "MCmap". Moving the data into the MCmap movie clip allowed the map to be controlled by ActionScript that could pan, zoom and re-center the map. The function of turning each map data layer on and off was accomplished through the use of ActionScripting and a checklist of external map files. Whenever a map file was loaded, it was assigned an identification number that Flash could use to communicate with the

5 Geographic Information, Multimedia and Landscape Modeling - Integrated Visualization Tools 5 external file and manage its layer stacking order. The menu for the map included two sections. The top section displayed a thumbnail representation of the State of Iowa. Clicking on this small map re-centered the larger map to the point selected making it easier to navigate. The menu also contained several tabbed panes allowing the user to change between navigation tools and map legend information. Identifying the UTM Zone 15, NAD 83 X, Y coordinate for the top left corner of a rectangle surrounding the map, provided geo-referencing of the base map. MAPublisher provided a tool within Illustrator to identify this location. This information was stored in a variable as part of the Flash file. ActionScript was used to record the X, Y screen coordinates of the mouse and convert these coordinates to geographic coordinates based on the distance from the top left corner of the map. This information was updated every half second and displayed in one of the tabbed menu panes. Placing all of the 300+ aerial photographs of the corridor into the Flash file would be memory intensive, so the files had to be dynamically loaded into the map when requested by the user. One of the new features of Macromedia Flash MX is its ability to dynamically import JPEG image files when requested through ActionScripting. Identifying which aerials to display required a conditional script to check an index table to see if the area covered by the aerial or digital raster graphic was included within the limits of the portion of the map displayed on the screen. If an image's coordinates were within the boundaries of the viewed area a new movie clip was dynamically created and the image was loaded into the movie clip. The movie clip was then placed at the correct location on the base map. The aerial imagery files used for the project measured 800 x 800 pixels and had a resolution of 10 meters per pixel. Once loaded from the DVD raster images remained on the screen until the user cleared them using the clear raster graphic button in the map menu. Aerial images could also be loaded from the Internet if the requesting SWF file resided on the same Internet domain as the aerials (CHAMBERS, 2002). Zooming capability was provided by enlarging or decreasing the size of the nested MCmap clip (SEEGER, 2002). Once the map scale had changed, the geographic offsets from the original location were calculated and the new geographic coordinates were applied. 3.4 Video Implementation A total of twenty-four 80-minute DV tapes were required for the entire corridor. Each tape required approximately 18.5 Gigabyte of storage, 444 Gigabyte for the entire corridor. Using the Sorenson 3 CODEC, each video was reduced to a resolution of 320 x 240 and a frame rate of 15 frames per second (FPS) resulting in a 160 Megabyte file for each tape. The settings for the compression values were based on the need for the entire corridor video to fit on a 4.4 Gigabyte DVD. The result was 3,840 megabytes of video. After compressing the video, the files for each of the three video views were combined and stored as single linear files for the entire length of the corridor in each direction, i.e. 6 video files for Interstate 80 and 6 video files for Interstate 680. Using the mile markers on the roadway as an index, each of the video files contained a cue point at the beginning and end of a mile segment. This cue point was used by Lingo to identify the location to play when either the map or the text mile marker were used to

6 6 C. J. Seeger search for video. Users wishing to use the map to select a video need only click on a dot placed at the mile marker location. The video controller kept the three video files synchronized and allowed the user to select between east and west bound. 3.4 Media Resource Bin Design The media bin was designed to be a location where additional resources pertaining to the mile section could be displayed. Using an index of file names and geographic coordinates, Lingo was used to create a list of resources and display thumbnails of the photos, QuicktimeVR, World Construction Set animations and other visualization media that was available. Clicking on the thumbnails opened a new view window containing a larger view of the media as shown in Figure 2. Figure 2. Example screenshot of an enlarged photo selected from the media resources bin, the text under the photo list the name of the image file. 3.5 User Comment Display The user comment display window is also linked to the mile marker sections and direction of travel. Storing the files on an Internet server allows users to have access to up-to-date comments without the need for distributing new DVDs each time the content is changes.

7 Geographic Information, Multimedia and Landscape Modeling - Integrated Visualization Tools 7 Again, Lingo is used to contact the FTP site and parse the existing text document for use with the viewer application. 4 Results & Discussion Although the viewer is still in the prototype stage, it has already proven beneficial for the design team by providing a way to quickly review any section of the corridor and to comment about special features found within each mile section. As the management plan for the corridor is prepared, the viewer will serve as a repository of information about the corridors numerous resources. The SWF format is easy to work with as a graphic element, but support for linking attribute data to individual objects is not supported to a scale that would allow it to be used in large geographic areas. The SVG file format may be the solution to this problem. As SVG gains in functionality, it may be possible to incorporate its attribute link capabilities into the viewer allowing for GIS type querying of displayed mapped data. At the completion of this project, the resource viewing application will be distributed to community leaders, local governments, planners and state officials as a tool for making better informed decisions when considering zoning and development changes to the corridor. Since the entire state was used as the base map the viewer can also be easily reconfigured for other corridor projects. Additional images of the interface and an update to this paper will be available after the conference at 5. References Chambers, M. (2002): White Paper: Macromedia Flash MX Security. San Francisco. Discreet. (2002): Cleaner 6 User Guide. Autodesk, Inc. Franklin, D. and J. Makar. (2002): Macromedia Flash MX ActionScripting: Advanced Training From The Source. Macromedia Press, Berkeley, California, USA Gross, P. and J. Roberts. (2000): Director 8 Demystified: The Official Guide to Macromedia Director, Lingo and Shockwave. Peachpit Press, Berkeley, California, USA Pratt, M. (2001): Hot Linking with ArcView GIS. ArcUser. 4(1): Preloznik, U. (2002): SVGMapper Released for ArcView GIS. Seeger, C. (2002): Identifying the Image of Iowa Along Interstate 80: A Method to Increase Public Participation. ESRI User Conference, San Diego, California, USA.