analysis grid superimposed 2d street grid calculating travel-time …vector to raster conversion...

Analysis grid superimposed

2D Street Grid

Calculating Travel-Time…vector to raster conversion

Note that a 100 row by 100 column analysis grid (10,000 cells) is superimposed on the street data and those cells containing a road are assigned a friction value representing the typical time to traverse each location– primary streets (red) = 8.5 seconds; secondary streets (blue) = 25.5 seconds.

2D Street Grid

3D Street Grid

Calculating Travel-Time…street types as relative barriers

Note that the street pattern can be displayed as 2D and 3D plots. The street pattern can be conceptualized as a canal network that connects Kent’s Emporium to its customers.

Kent’s Emporium

2D TTime_0-10

3D TTime_0-10

Calculating Travel-Time…”splash” 0-10 cells = 0 to 1.4 minutes

Base cell = 8.5sec = .1424min

Note that the distance “waves” begin to move away from Kent’s Emporium along the “canal” pattern (streets) like ripples from a rock tossed into the water. The distance waves accumulate the time it takes to cross each grid cell– considering the relative impedance for primary (8.5sec) and secondary (25.5sec) streets.

2D TTime_0-20

3D TTime_0-20

Calculating Travel-Time…0-20 cells = 0 to 2.8 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-30

3D TTime_0-30

Calculating Travel-Time…0-30 cells = 0 to 4.3 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-40

3D TTime_0-40

Calculating Travel-Time…0-40 cells = 0 to 5.7 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-50

3D TTime_0-50

Calculating Travel-Time…0-50 cells = 0 to 7.1 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-60

3D TTime_0-60

Calculating Travel-Time…0-60 cells = 0 to 8.5 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-70

3D TTime_0-70

Calculating Travel-Time…0-70 cells = 0 to 10.0 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-80

3D TTime_0-80

Calculating Travel-Time…0-80 cells = 0 to 11.4 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-90

3D TTime_0-90

Calculating Travel-Time…0-90 cells = 0 to 12.8 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-100

3D TTime_0-100

Calculating Travel-Time…0-100 cells = 0 to 14.2 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-110

3D TTime_0-110

Calculating Travel-Time…0-110 cells = 0 to 15.7 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-120

3D TTime_0-120

Calculating Travel-Time…0-120 cells = 0 to 17.1 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-130

3D TTime_0-130

Calculating Travel-Time…0-130 cells = 0 to 18.5 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-140

3D TTime_0-140

Calculating Travel-Time…0-140 cells = 0 to 20.0 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-150

3D TTime_0-150

Calculating Travel-Time…0-150 cells = 0 to 21.4 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-160

3D TTime_0-160

Calculating Travel-Time…0-160 cells = 0 to 22.8 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-170

3D TTime_0-170

Calculating Travel-Time…0-170 cells = 0 to 24.2 minutes

Base cell = 8.5sec = .1424min

2D TTime_0-180

3D TTime_0-180

Calculating Travel-Time…0-180 cells = 0 to 25.6 minutes

Base cell = 8.5sec = .1424min

Results displayed in a Desktop Mapping system (raster to vector)

2D TTime_0-180

Calculating Travel-Time…0-180 cells = 0 to 25.6 minutes

Base cell = 8.5sec = .1424min

Note that of the 10,000 cells comprising the analysis grid, 4123 do not contain a road. Of the 5877 cells with a road, 3014 locations (a little over 50 percent) are 0 to 70 effective cells away, or about 10 minutes from Kent’s Emporium (non-shaded area of the summary table)

Calculating Travel-Time

For more discussion on travel-time calculation and its applications, visit…

www.innovativegis.com/basis

…educational software for hands-on experience in creating and using travel-time maps and other grid-based map analysis

…online book discussing travel-time concepts, procedures and considerations (Topics 5, 6, 13,14 and 17), as well as other grid-based analysis techniques

…also see Papers/Presentations Online Papers, select “Understanding Effective Distance and Connectivity”