Special Topics in Geo-Business Data Analysis Week 2 Covering Topics 4 and 5 Spatial Analysis Analyzing Location

Classes of Analytical Operations (Berry) Statistics— numerical relationships within and among mapped data Reclassify— reassigning map values without creating any new spatial information Overlay— two or more maps that results in delineation of new spatial information based on spatial coincidence Distance— generate entirely new information by characterizing the relative positioning of map features Neighbors— summarize the conditions occurring in the general vicinity of map locations

Simple Buffers (Berry) Simple Buffer— identifies all locations within a specified distance from a map feature (points, lines or polygons) Proximity Buffer— identifies increasing distance zones from a map feature

Travel-Time Waves (Berry) Travel-time is computed as a series of increasing waves moving away from a starting location that are constrained by the street network.

Generating an Effective Travel-time Buffer (Berry) (a)superimposition of an analysis grid over the area of interest (b)“burns” the store location into its corresponding grid cell (c)“burns”primary and residential streets are identified (d)travel-time buffer derived from the two grid layers

Proximity Buffer Based on Travel-time (Berry) Note that the farthest location from the store appears to be about 20 minutes away and is located in the northwest corner. While the proximity pattern has the general shape of concentric circles, the effects of different speeds tend to stretch the results in the directions of the primary streets.

Transferring Data to the Pseudo Grid (Berry) The travel-time map can be imported into most generic desktop mapping systems by establishing a pseudo grid

Utilizing Pseudo Grid Information (Berry) Travel-time and customer information can be joined to append the effective distance from a store for each customer

Joining Attribute Tables (Berry) A “spatial join” identifies points that are contained within each grid cell then appends the information to point records The appended travel-time information can be utilized in traditional geo-query and display

Calculating a Viewshed (Seen, Not Seen) (Berry) Identifying a viewshed is analogous to noting the areas illuminated by a search light Tangent = Rise / Run

Calculating Visual Exposure (# Times Seen) (Berry) Visual exposure identifies how many times each map location is seen from a set of viewer locations

Visual Exposure from Extended Features (Berry) A visual exposure map identifies how many times each location is seen from an “extended eyeball” composed of numerous viewer locations (road network)

Weighted Visual Exposure (Sum of Viewer Weights) (Berry) Different road types are weighted by the relative number of cars per unit of time …the total “number of cars” replaces the “number of times seen” for each grid location

Visual Vulnerability Map (Berry) A Visual Vulnerability map identifies areas of high visual exposure– more than 5,000 car-cells per hour are visually connected

Visual Aesthetics Map (Berry) An aesthetic map determines the relative attractiveness of views from a location by considering the weighted visual exposure to pretty and ugly places

Real-World Visual Analysis (Berry) Weighted visual exposure map for an ongoing visual assessment in a national recreation area— the project will develop visual vulnerability maps from the reservoir in the center of the park and a major highway running through the park. In addition, aesthetic maps will be generated based on visual exposure to pretty and ugly places in the park

Comparison of Visual Analysis Results (Berry) Visual exposure maps for a pilot area were generated using ArcGIS and Map Calc operations… Both maps displayed using Standard Deviation color pallet ArcGIS Solution MapCalc Solution

Travel-Time Surfaces from Two Locations (Berry) Travel-time surfaces show increasing distance from a store considering the relative speed along different road types— from Kent’s (left) and from Colossal (right)… …recall that travel-time is calculated by starting at a store then moving out along the road network like waves propagating through a canal system …as the wave front moves, it adds the time to cross each successive road segment to the accumulated time up to that point …propagate like ripples from a rock tossed into a pond

Deriving a Competition Surface (Berry) Subtracting the two surfaces derives the relative travel-time advantage for the stores… …what do you think would be the interpretation of the resultant map is you added them? …3D view of travel-time advantage surface as peaks (red) for strong advantage and intervening valley as minimal advantage (yellow)

Analyzing Accumulation Surfaces (Berry) Accumulation surfaces compute aggregated movement respecting absolute and relative barriers (cost) …subtracting two accumulation surfaces creates a competition surface… …adding two accumulation surfaces creates an opportunity cost surface that identifies the additional cost to force a path through a location not on the optimal path

Characterizing Customer Loyalty (Berry) Survey respondents indicating their preference for Kent’s Emporium or Colossal Mart are summarized by travel-time zones to derive customer loyalty

Optimal Path Delineation (Berry) The height on the travel-time surface identifies how far away each location is and the steepest downhill path along the surface identifies the quickest route

Optimal Path Applications (Berry) The Optimal Path (quickest route) between the store and any customer location can be calculated then transferred to a standard desktop mapping system The region of influence, or Catchment Areas, is identified as all locations closest to one of a set of starting locations (basins)

Suitability Modeling (Cabin Country Development) (Berry)

Suitability Modeling (Implementation) (Berry)

Capturing Model Logic (Command Script) (Berry) The logical sequence of map analysis operations is contained in a command script that can be easily changed to simulate different scenarios

Spatial Reasoning and Dialog (Berry)