Specifications:

3.3 Post-Processing

The survey data was exported as a Shapefile for data exploration in Python and visualization in ArcGIS. Symbology was used to generate intuitive outputs for decision-makers, such as a map output with curbs color coded by overall condition classification (from '1 / very poor' in red to '5 / very good' in green) and other attributes (such as excessive lip / bump measurement shown with polygon markers). Bar charts and pie charts were generated to show basic descriptive statistics of the curbs.
The Structure Sensor and P40 data was exported in point cloud form and manipulated with CloudCompare software. For the laser scanner, the point cloud captured the whole street scene including surrounding building facades in extremely high detail. The area of interest (curb dimensions) was extracted. Based upon this smaller area, CloudCompare was used to generate physical measurements. Using our priority data point scheme, measurements were generated for ramp width, lip / bump height, and other data points including slope elevation.
Due to GPS location inaccuracy, a necessary post-processing step was to manually move each Geodatabase record (corresponding to a single curb cut) to its true location. This was done in ArcGIS using the Move tool, based upon the street intersection and curb cut orientation attributes. This step was time-consuming, prompting us to consider methods to automate the process (see discussion below).

4. Results

4.1 Survey Results

Out of 42 curb cuts surveyed, the survey pinpointed many with poor or very poor condition, and other newly renovated curbs classed as 'very good', with the mean condition rating for Union Square to 26th St being 3.7. Fully one-quarter of the curbs surveyed had a lip / bump measurement of more than 1 inch, signaling a failure of ADA compliance on this measure alone.
The visualizations give a clear picture of where ADA-uncompliant curbs are located across this stretch of Broadway. For each uncompliant curb, decision-makers may pull up a photo from the Geodatabase. To facilitate data visualization, a web map was created using ESRI software. The web map is available at http://bit.ly/2w8mmZk. The map includes 'bookmarks' allowing the user to navigate to several key landmarks along the survey route, including the Flatiron Building and the key study site of Broadway and 26th Street. Color-coded condition ratings visualize the curb cut quality. Users can query the curb cut measurements by clicking on any individual point; an intended extension would be to make the photo of each curb accessible by clicking on it.