---
title: 3.3.4 Overlay annotations upon an isovist field
description: "![](http://isovists.org/wp-content/uploads/2020/07/Vectors-1280x559.jpg) *Above: Flow vectors overlaid upon an average radial field in Mies’ Barcelona Pavilion* A series of drawing overlays can be calculated and displayed over the isovist fields. To draw these: - Import and set up a drawing for field…"
url: "https://isovists.org/user-guide/3-3-4-overlay-annotations-upon-an-isovist-field/"
updated: "2021-04-05"
category: 3 How To... / 3.3 View and Export Results
---

# 3.3.4 Overlay annotations upon an isovist field

![](http://isovists.org/wp-content/uploads/2020/07/Vectors-1280x559.jpg)

*Above: Flow vectors overlaid upon an average radial field in Mies’ Barcelona Pavilion*

A series of drawing overlays can be calculated and displayed over the isovist fields. To draw these:

- Import and set up a drawing for field analysis as normal.
- Open the ‘Field Analysis menu’, and run the analysis in the advanced mode if all measures are required.
- Select a field analysis for display on screen from either the ‘Isovist’ or 'Space Syntax’ measures options. Wait… for the data representation to reach a stable condition.
- Select the ‘toggle overlays’ option and switch the required overlay type on or off:
  - Select ‘overlay absolute values’ to display point values within the field at the cursor location
  - Select ‘overlay sample locations’ to view all stochastic sample points assessed so far in the field
  - Select ‘overlay plan annotations’ to switch the drawing annotations layer on and off
  - Select ‘overlay flow vectors’ to draw a series of vector lines that indicate the direction and magnitude of the field results at locations throughout the space.
  - Select ‘overlay spatial partitions’ to display an estimated set of Peponis’ E- and S-Partitions (Peponis, 1997) based on the analysis space and isovist types.
  - Select ‘overlay persistent thresholds’ to reveal experientially key thresholds in the analysis space.
  - Select ‘overlay quad-tree grid’ to reveal the underlying search structure used to calculate visibility in the analysis space.

*Below: Switching between different plan overlays in Mies’ Barcelona Pavilion*

[https://player.vimeo.com/video/442128290?autopause=0&autoplay=1&muted=1&loop=1&title=0byline=0&portrait=0](https://player.vimeo.com/video/442128290?autopause=0&autoplay=1&muted=1&loop=1&title=0byline=0&portrait=0)