The Magnitude Grid: From manual assessment to repeatable analysis
The methodology
NSW's Large-Scale Solar Energy Guideline requires visual magnitude — how much of someone's field of view a solar farm will occupy — to be measured objectively rather than judged by eye.
The method overlays a 180° panorama with a grid of cells, each 1° high by 10° wide. Cells containing 25% or more development are counted, with the total mapping to one of five magnitude ratings from very low to very high.
Where it breaks down in practice
On paper, it's simple. In practice, it's surprisingly manual.
Each partially occupied cell has to be assessed to determine whether development covers more or less than 25%. The guideline also allows the grid to be repositioned to minimise split cells — but every adjustment means assessing and counting the cells again.
Across a project with 40+ viewpoints, that becomes a significant task. More importantly, it introduces two sources of variability into a process intended to be objective: grid position and the judgement of borderline cells.
What we built instead
Our Magnitude Grid Analyser automates both.
The analyser computationally searches the possible grid offsets to identify the position that minimises split cells. It then measures development coverage within every cell pixel-by-pixel, applying the 25% threshold mathematically rather than estimating it by eye.
Modata Magnitude Grid Analyser
The result is:
Efficient — seconds per image rather than repeated positioning and counting
Consistent — every image follows exactly the same process
Accurate — cell coverage is calculated rather than estimated
Defensible — results are reproducible and individual cell measurements can be checked
Batchable — an entire project can be processed in one pass
A zoomable preview allows edge cases to be reviewed, with a compass overlay providing orientation reference.
The result is a fast, repeatable and transparent workflow that retains the methodology prescribed by the guideline while removing much of the manual interpretation.