Potential Analysis

Description

Issue

"Potential analysis" aims at specifying, through a colouring gradation, the most attractive zones to settle one's activity. Considering the conditions the user defined, this module emphasizes the areas that best fulfil the requirements.

Exemple : implanter un nouveau magasin peut nécessiter une forte concentration de futurs clients potentiels, avec des revenus élevés, d'être proche des voies de communication, et loin des magasins concurrents.

E.g.: implementing a new store requires high potential customer's concentration, high income level, close location to transportation ways, farther location from competitors.

Principle

Potential index is computed based on strength and weakness of one or many statistical variables associated to the working map of your area of study.

It also takes into consideration proximity or distance from networks (rivers, highways, rail ways ...), specific spots (plants, competitors, partners, ...) or polygons (shopping precincts, protected areas, ...) on your area of study, depending whether these parameters are attractive, blocking or repulsive.

Involved data and working maps can be balanced by a determined ratio, so you can increase, or decrease, the importance of one factor in the computation of your potential index.

The result of this operation is your Potential index (all the factors and their associated weight are computed), applied upon a regular "grid" (see Grid module), switched into isovalue areas and then displayed on the map with colouring gradation

Interface & connection

Connecting many modules as inputs of the Potential analysis module is required. Those inputs represent each criterion that defines the potential of each working map :

• One or more working maps : Working maps defined as inputs can contain spots, networks (lines), or polygons. They represent key elements from the map that can generate attraction (to reinforce the potential of the area), generate repulsion (to decrease the potential of the area) or block the attraction of a specific area (potential equals zero when close to these elements of the working map).
• One or several continuous data : Data can be relative (rates, density, portions...) or absolute. (number of inhabitants, housings, companies, ...). The higher their value, the greater the potential, and reciprocally.

Once each input module is connected, the following interface helps you define the parameters of the Potential Analysis module :

For each set of data, you can customize:

• Its type : the combo box below helps you define whether your set of data is relative or absolute.
  
  To integrate this set of data without it to be integrated in the potential index computation, use the "Simulation only" mode. This way, you can use it later in the "Setting-up optimization" module
• Its coefficient : associate a coefficient to each set of data to reinforce or decrease its consideration in the potential index computation.

For each working map (networks) including an interaction with the potential index computation, you can customize :

• Its type : the combo box below helps you define whether your set of data is relative or absolute.
  
  A specific network can be "Attractive" (its coefficient is positive, hence a positive potential value at the periphery), "repulsive" (its coefficient is negative, hence a negative potential value at the periphery), or "blocking" (its coefficient equals zero, hence a null potential value at the periphery)
• Its coefficient : associate a coefficient to each set of data to reinforce or decrease its consideration in the potential index computation
• Its style : Select your working map outlines colour that you want to be displayed on the final map. In case your working map is made of spots, you can select the symbol you want to display on every spot
• Its size : you can control thickness of your working map outlines, or the size of the displays spots

It is necessary that you define the scope of action of networks, i.e. the distance on which their "attractive", "repulsive" or "blocking" feature will apply

• Small scope : the scope of action distance is worth 10% of the maximum length or height of the map
• Medium scope : the scope of action distance is worth 20% of the maximum length or height of the map.
• Big scope : the scope of action distance is worth 30% of the maximum length or height of the map.

You can now define the parameters of your result accuracy and computation time :

• Standard mode : The module works on a small-squared grid and requires a longer calculation time, due to a greater accuracy of result.
• Draft mode : The module works on a wide-squared grid and requires a shorter calculation time, at the expense of the accuracy of result. It helps to pre-visualize the result before running computation under the "Standard mode"

Method for calculating potential index :

The Potential Analysis module determines potential index and displays its cartographic result following these stages :

1. Network scope of action calculation : the scope of action is calculated in the working map unit according to the user choice: 10% (small), 20% (medium) or 30% (big) from the greatest size of the map (width or height).
2. Creation of analysis grids : for each working map (networks) and for each linked data, "potential analysis" module draws a grid (regular squares) that is overlaid on the working map. Statistical data are retranscribed on these squares to obtain a value "per square". The aim is to standardize the statistical data on identical and comparable geographical areas (squares) in order to calculate into a single scale (the square). An additional blank grid (Grid Result) is also created to display the final result which is the potential index.
3. Squares value calculation : once the grids are created, the " potential analysis " module calculates a value for each square :
4. • a. Grid applied to a data : statistical data are distributed on the squares according to the grid module method and to the data type (Relative or Absolute).
   • b. Grid applied to a network : the "potential analysis" module calculates the distance between each square and the nearest geographical object from the related network. The distance assigned to each square is null for the squares out of the scope of action defined by the user. The final value of each square is a continuous data between 0 and 1 and is equal to :
     1 - (distance in the working map unit / scope of action in the working map unit)
5. Then data are centred (between 0 and 1)
6. For grids linked to data, the user coefficents are applied to the value of each square.
7. For grids related to networks (working maps), the user coefficents are applied according to the network type :
8. • "Attractive" network : the coefficient stays the same.
   • "Repulsive" network : the user coefficent becomes negative before being applied (ex : a coefficient "2" becomes "-2").
   • "Blocking" network : the coefficient applied must be "0" and thus generates a null result.
9. The "potential analysis" module calculates the potential index according to the following calculation :
   (data A * coefficient A) + (data B * coefficient B) + (data D * coefficient D) + etc.
   
   The following diagram details this operation :
   

   With : (1) : Grid "D Data" * "d Coefficient" (2) : Grid "C Data" * "c Coefficient" (3) : Grid "B Data" * "b Coefficient" (4) : Grid "A Data" * "a Coefficient" (5) : Result Grid : (A.a+B.b+C.c+D.d)

   The light or dark colors of the squares correspond to a more or less strong value calculated for each square.

   
   Potential index can be defined as the sum of the square values balanced by the coefficients that are chosen by the user
10. Each square now has a potential index quantified by a value. A level 3 smoothing (cf. Grid module) is applied on this data to reveal the main space tendencies of potential distribution.
11. The potential simulation setting-up study makes a quantification of this "potential index" in 10 classes according to the "equal sizes" method. It displays a colour gradation.
12. A calculation of isolines (cf. Isolines module) is used to reveal zones instead of grid squares. It also smoothes the aspect of the squares.
13. The module displays the colour gradation on the map and on the networks implied in the operation, according to the parameters entered by the user

This module can be linked to the setting-up simulation module to simulate an activity setting-up on the zones determined by the potential analysis (cf. Setting-up Simulation).

Script :

2      module untyped_list ""
3        mod_type integer "104"
3        mod_subtype integer "616"
3        mod_name string "Etude de potentiel"
3        mod_dads integer_list ""
4          ? integer "7"
4          ? integer "6"
4          ? integer "8"
4          ? integer "9"
4          ? integer "12"
4          ? integer "13"
3        caption_origin vector ""
4          x_val double "0"
4          y_val double "0"
4          z_val double "0"
3        map_bounds bounds ""
4          bottom_left vector ""
5            x_val double "427.10001"
5            y_val double "2194"
5            z_val double "0"
4          top_right vector ""
5            x_val double "526.59998"
5            y_val double "2302.3"
5            z_val double "0"
3        dad_info_list untyped_list ""
4          dad_info untyped_list ""
5            dad_name string "N152"
5            dad_type integer "3"
5            dad_coeff double "0.5"
5            dad_color fill ""
6              fill_color fill_color ""
7                red255 integer "132"
7                green255 integer "185"
7                blue255 integer "6"
7                hue360 integer "77"
7                light255 integer "95"
7                saturation255 integer "238"
6              hatch hatch ""
7                angle1 double "0"
7                angle2 double "0"
7                desc_list1 double_list ""
7                desc_list2 double_list ""
7                is_weft boolean "T"
6              has_hatch boolean "F"
5            dad_size integer "1"
4          dad_info untyped_list ""
5            dad_name string "tours"
5            dad_type integer "4"
5            dad_coeff double "1"
5            dad_symbol string "sphere_Rouge.png"
5            dad_size integer "1"
4          dad_info untyped_list ""
5            dad_name string "IndreEtLoire_routes.vxf"
5            dad_type integer "3"
5            dad_coeff double "0.25"
5            dad_color fill ""
6              fill_color fill_color ""
7                red255 integer "209"
7                green255 integer "243"
7                blue255 integer "71"
7                hue360 integer "71"
7                light255 integer "157"
7                saturation255 integer "223"
6              hatch hatch ""
7                angle1 double "0"
7                angle2 double "0"
7                desc_list1 double_list ""
7                desc_list2 double_list ""
7                is_weft boolean "T"
6              has_hatch boolean "F"
5            dad_size integer "1"
4          dad_info untyped_list ""
5            dad_name string "nb camping pour 1000 habs"
5            dad_type integer "0"
5            dad_coeff double "1"
4          dad_info untyped_list ""
5            dad_name string "nbCamping02"
5            dad_type integer "0"
5            dad_coeff double "3"
4          dad_info untyped_list ""
5            dad_name string "0-25ans"
5            dad_type integer "0"
5            dad_coeff double "1"
3        prj_color fill ""
4          fill_color fill_color ""
5            red255 integer "80"
5            green255 integer "175"
5            blue255 integer "118"
5            hue360 integer "144"
5            light255 integer "127"
5            saturation255 integer "95"
4          hatch hatch ""
5            angle1 double "0"
5            angle2 double "0"
5            desc_list1 double_list ""
5            desc_list2 double_list ""
5            is_weft boolean "T"
4          has_hatch boolean "F"
3        action_ray_size integer "0"
3        calc_quick boolean "F"