Overall model structure

MtM ABM description

Author

David O’Sullivan

Published

February 19, 2025

Modified

August 5, 2025

The model interface

The easiest place to start is with an overview of what the model looks like. At time of writing (early August 2025) the GUI appears as below (click on the image for a closer look):

Column 1

Controls on the left-hand side are primarily starting and running the model and controlling display of visual elements.

Column 2

The map area shows land use capability (LUC; more intense colours are better land) and land use according to the following key:

  • Greens Forest
  • Blues Dairy
  • Oranges Sheep and beef (SNB)
  • Purples Crops

Farms are delineated in black and their current profit is shown by a circle scaled by the level of profit. If ‘in the black’ the circle is coloured to match dominant land use on the farm. If the farm is losing money (‘in the red’) the circle is coloured red.

Holdings are delineated in grey and shown by squares scaled and coloured in the same way as farms.

Farmers are shown as ‘person’ icons, with no additional information symbolised.

Column 3

Controls immediately to the right of the map area mostly affect model initialisation, in particular (i) allowing choice between a random map, or initialisation from GIS data (shown above), and (ii) allowing for initialisation from controlled :random number seeds to allow for repeatability of results and exploration of the details of any findings. For GIS initialisation a region is chosen from a drop-down list. For initialisation of ‘market’ settings a scenario is chosen from a drop-down list. More details on the requirements for these options are provided elsewhere in the documentation.

One other important setting is controlled by a ‘slider’: sigmoid-slope controls the rate of change of probabilities of adoption of intervention in response to push and pull factors. This is uncalibrated at present. A potential extension of the model would allow different levels of this control for different ‘nudge’ or market effects.

Column 4

The column of controls on the right of the model provides some tracking plots (overall income and costs, overall land on which different interventions have been adopted, overall land in different land uses, and aggregate environmental impacts), and also some high level controls as follows:

  • landuse-change-on-succession?: If On when a farmer is succeeded by a new entrant the new farmer considers a change in (all of farm) land use if any of the farm’s holdings are losing money.
  • prioritise-forestry?: If On when a holding is unprofitable only forestry is considered as new land use; other land uses are also considered if this option is Off.
  • apply-severity-of-losses?: If On losses occurring across more of the farm (by area) make whole of farm conversion of land use less unlikely.
  • apply-suitability?: If On suitability of LUC of holdings is taken into account when land use change is undertaken; if Off land use change disregards LUC.
Date Changes
2025-02-19 Initial post.
2025-08-05 Original page broken out into 3 - overview, elements, files.