A Graphic Tool For Calculating Spatial Openness Index

Written by:
Dmitry Batenkov
Ben Riva

Under the supervision of:

Dr. Israel A. Wagner,

Faculty of Computer Science, Technion and IBM Haifa Labs

Dr. Dafna Fisher-Gewirtzman,

Faculty of Architecture and Town Planning , Technion

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This is a project which has been done in the framework of the Advanced Programming Course at the Technion - Israel Institute of Technology.

Following is a brief description of the tool and its purpose.

Table Of Contents


    Brief Overview

    Links & Bibliography


The perceived density is one of the main parameters determining the quality of life in a densely built environment. The Spatial Openness indicates the volume of free space measured from an observation point. A correlation has been found between the Spatial Openness Index (SOI) and the perceived density in a built environment (see [1] for details).

The main purpose of the project was to build a user-friendly graphic tool, which would enable the user to schematically design various built environments and to calculate the Spatial Openness Index measured from all the built units as well as from certain observation points according to the needs of the designer. In addition, it is possible to assign different weights to different views around the evaluated built environment. A certain view (direction) can be assigned an enhanced value, thus making this direction preferable (it will have greater SOI).

The tool is designed for architects and urban designers.

This tool is an advanced development of a previously created tool for calculating SOI, the SOI Calculatoion Applet.

Brief Overview


Written in MATLAB (version 6.0 and higher)

Support of file I/O

VRML conversion

Support of large environments

Support of weighted (non-uniform) views

Relatively fast algorithm

Easy-to-use, user-friendly GUI

Visual representation of calculation results

Command-line (scripts, batch files) support

The tool is run from the MATLAB workspace.

Building environments

Environments could be opened/saved on disk for future use, as well as converted to the VRML format.

Two views of the environment:

Main 3D view (right): the entire environment, including the weighted view values

Auxiliary 2D view (left), the built units and observation points at a specified height

The z-level plane (Main View), indicating the height which is shown in the Auxiliary View

One mouse-click insertion/deletion of units

Standard MATLAB figure tools (rotation, zoom, camera motion etc.)

Unit counters, in order to simplify comparing various configurations

Visual representation of calculation results

The results can be loaded/saved/converted to VRML.
The differences in SOI of various units can be visually seen
SOI of every unit can be examined by highlighting the unit with the mouse
Overall Statistics of the SOI values are presented
SOI values distribution is plotted as a colored histogram


With this tool, comparing between various built configurations is very easy.

If, for example, a designer wished to verify which configuration is preferable given fixed number of built units, he/she can just display the result windows one next to the other:

Or see the results in textual format:

Links & Bibliography

  1. “Spatial Openness as a Practical Metric for Evaluating Built-Up Environments”, Dr. Dafna Fisher-Gewirtzmann, Dr. Israel A. Wagner
  2. The SOI Calculator
  3. MATLAB Website

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