Friday, June 19, 2009

Website progress and collaboration information

I have nearly completed the NIJ project webpage. I am only missing a few pieces from Jianfei and Jason for the 3-d Visualization page and Mobile app page. Overall, it seems to be functioning correctly and working the way I set out for it to be.

The collaboration with Sayeed and Dr. Raam seems to be going well. I have created a conceptual network for their algorithm to output routes to. Their output comes in the form of a text file with edge numbers listed as integer values representing the edges that will be traversed.

The screenshot below represents the test network and a route that has been selected based on a query from their algorithms output:

Friday, June 5, 2009

Website Progress and Transition

Today I have been working on completing the website for the NIJ project. Currently, it is located at and the main design is completed. All that is left to be done is to fill in information for each section, or page of the site. I hope to complete this by next week, and I will be asking the other project members for input and any other information they deem necessary for the web page.

Regarding the transition with Jason, I have recently met with him last week to begin the process. I gave him information regarding the iPhone application progress and the tools that he will be using to complete the program. I will also begin the process of documenting such things as CAD file geo-referencing so that when I am gone these tasks can be completed with no problems.

Monday, April 13, 2009

We have been working hard the last few weeks on getting everything in place for the demo for NIJ in Annapolis. We plan on having two windows laptops, a client and a server, as well as the iPhone for the mobile device. The client will be reading from the server laptop which is running Postgres with PostGIS as the database backend. We are using Jianfei's NIJ Project program for the visualization of the data contained in this database.

We have successfully implemented this server and have demonstrated connectivity between the two laptops over wi-fi. We have tested the demo for building blocking and some other features and I hope that this will work at the hotel, last I heard they in fact do have wi-fi available.

The mobile app seems to be progressing alright, I have finally transferred the event handlers so that Openlayers will work successfully in the iPhone. The only thing to do now is to make sure that that we can read directly from the database that will be stored on the laptop.

I should be able to complete this by tomorrow, since time is quickly winding down.

Monday, March 30, 2009

Manual Processing and Centerline Identification for Woodward Hall and Cameron Research Institute

Without the use of the automated centerline extraction algorithm, the original hallway centerline files and junction (node) files were created manually in ArcGIS.

Assuming that we are using a georeferenced polygon shapefile or PostGIS table of the building’s rooms, stairways, and elevators we can begin the manual process of digitizing the centerlines. These centerline files are analogous to routes humans (in this case during emergencies), use to traverse the building and get from point A to point B.

In the case of Woodward Hall, I had already preprocessed the shapefiles containing the building geometry. Using the identified hallways in this building, I manually digitized these routes as line feature types in ArcGIS. This was achieved by a combination of “snapping” to the center of the polygon and manually drawing straight line segments to common junction points (i.e. the end of two hallways). After this step is completed, I have a file representing lines to all possible routes in the building, including access to rooms and other important features.

Using a tool called “network analyst” I was able to convert this line feature type into what is called a network shapefile, which creates junctions at the end of each edge in the graph. These junction points would be used to store attribute information on their specific function in the graph. For example, if a line segment ended by a main entrance, it would be specifically labeled to indicate this in the attributes of said line junction file. Or if the junction happened to fall on a stairway, as is the case in the screenshot below, we would label it as such. This continues until all rooms, elevators, stairways, and general hallway junctions are accounted for with a unique identifying label.

Line and Junction file for a sample floor. Hallway polygons are blue, rooms green, and stairways purple.

Identifying Junctions and Room #'s based on CAD file documentation and existing Polygon attributes.

Once everything is labeled properly, the files are uploaded into the PostGIS database. Before we developed our automation methods, our graph model used the tables representing the graph to programmatically construct a 3D graph in order to achieve route finding and other functions.

This is the result of the 3D Woodward hall graph running in our Visualization Program.

This is the graph running in ArcGIS, which did not support the 3D functionality required for multiple floors.

Another process that was completed manually, and in the future will also be automated, is the creation of hallway “segments” that we used for blocking sections of the building. These were created from the same polygon files from which centerlines were extracted from, and were representative of the area the entire hallway space covered. We divided these into sections that were delineated manually in ArcGIS and were intended to be representative of sections of the hallways for the purposes of creating something the user could easily click on to indicate an impediment in that section of the building.

Each different hallway color represents a different segment the user can select to block in the graph

This manual process of digitizing the hallway centerlines usually takes on average about 1 hour to actually create the centerline file, and another 1 or 2 hours to label the junction file after being converted into a network. If the following floors in the building are assumed to be of the same structure and composition, then these files can simply be copied to their equal on the second or remaining floors. Since this is rarely the case, (and in fact was not the case in both building files we presented as examples) each floor has to go through this manual process in order to generate the geometry required for graph construction.

Obviously, for large buildings of high-complexity these steps can take several full work-days (16-20 hours) to complete. Especially when you’re dealing with several buildings in an urban cluster environment, manual creation of the 3D graph model is not viable, and strengthens the argument for automation of these processes.