Why draw a legend
Most drawings carry a symbol key — a table down one side listing each device with its code beside it. Telling ZeroCount where that table is turns a guess into a certainty: instead of hunting the sheet for shapes that repeat, Auto Detect Symbols reads the key one row at a time, gets one candidate per row, and names each Detection group with the code printed in the legend.
That is worth doing on any busy sheet. A whole-drawing scan has to work out what counts as a symbol; a legend tells it outright.
A legend rectangle is just a marked-out area on the drawing. It does not change what is counted on its own, and it does not appear in the export.
Where the controls are
In the sidebar, above the marker list, click the AoIs, Legends & Zones button. The dropdown has four sections stacked down it. The second is Legends .
| Control | What it does |
|---|---|
| Lock legends / Unlock legends | Stops legend rectangles being moved or resized by accident. Deleting is blocked while locked. |
| Hide legends / Show legends | Turns the rectangles on and off on the drawing. A hidden legend is still used by the scan. |
| New | Draw a legend rectangle — arms the drawing tool and closes the menu. |
Below the header, each legend you have drawn is listed with its name and a delete button. The list reads No Legends until you draw one.
Drawing a legend rectangle
- 1
Zoom and pan so the whole symbol key is on screen. See Navigating the canvas.
- 2
Open AoIs, Legends & Zones and click New in the Legends section. The cursor becomes a crosshair and the header shows Current Tool: legend.
- 3
Drag a rectangle around the symbol column and its codes. Include the symbols and the text beside them; leave out the title block and any notes underneath.
- 4
Release. The rectangle is drawn in your legend colour and appears in the Legends list as Legend 1.
Draw around the symbol column and the codes, not the whole table. Long description text is not needed and a wide rectangle catches more of the sheet's linework than it needs to.
To abandon a rectangle part-way through, press Esc, or click the Current Tool button in the header.
Renaming, hiding and deleting
- Rename — click the legend's name in the list and type. Press Enter to commit or Esc to go back to the old name.
- Show or hide — use the button on the Legends header row. This affects every legend on the drawing at once.
- Lock — use the button. Locking is worth doing once your legends are placed, so they cannot be nudged while you work.
- Delete — click on the legend's row. While legends are locked, the delete button is greyed and hovering it says Unlock legends before deleting. Unlock first, then delete.
Legend rectangles are stored against the drawing. On installations where that has not yet been switched on at the server, a legend may not be there when you reopen the drawing — draw it again before you run the scan.
How Auto Detect Symbols uses it
With at least one legend rectangle on the drawing, Auto Detect Symbols (scan drawing) switches to legend mode and stops scanning for repeats altogether. The window says Symbols read from the drawn legend, one per row.
What changes:
- One candidate per legend row, in the order the rows appear, instead of a ranked list of whatever repeated most.
- Each candidate is named from the legend. The leading code on the row becomes the Detection group's name, so you get EXT/1 rather than Group 3.
- The legend's own copy is skipped. The symbol printed in the key is a reference, not an installed device, so it is left out of the count. Your totals stay honest even with the key on the same sheet.
If the rectangle turns out to hold no usable symbols, the scan falls back to reading the whole drawing and tells you so: No symbols were found inside the drawn legend, so the whole drawing was scanned instead. Check the legend rectangle covers the symbol column. That is almost always a rectangle drawn slightly too high or too narrow. Adjust it and scan again.
Tips for a legend that reads cleanly
- One rectangle per column. If the key is split across two columns, draw a rectangle round each. They are all read together.
- Keep the rows separate. ZeroCount works out where each row starts and ends from the spacing of the text and the symbols. A key with unusually tight line spacing may merge two rows into one.
- Codes are short. Only a short leading code is taken as the name — something like
EXT/1orPIR. A long description stays out of the group name. - Do not include the border. A heavy box drawn around the key is linework the scan has to discount. Draw just inside it.
- A legend on a different scale will not match. Some drawings print the key at a different size from the plan. If the scan finds the symbols in the key but nothing on the drawing, count that symbol with Detect New Symbol instead.
Next steps
- Auto Detect Symbols — run the scan and pick which legend rows to count.
- Areas of interest — restrict detection to part of the sheet.
- Detect New Symbol — count anything the legend does not cover.
- Detection tips — what to change when a symbol is under-counted.
- Legend-based auto-detection — the older whole-drawing legend flow, for background.