Drag the bar beside the Polygons panel to resize it (arrow keys when it has focus; double-click resets). Everything is also in the toolbar on the map and the right-click menu. Polygons are saved in this browser only.
Add layer (Layers panel): view and snap to a GeoJSON/JSON file, a zipped shapefile or an ArcGIS REST layer address (ArcGIS Online, gis.nola.gov, maps.nola.gov or eocgis.nola.gov only). Imported layers are not editable, show only what lies inside the image, and are gone when you reload; the Hidden snap switch also covers them. Q copies an imported polygon's outline.
Auto merge (toolbar switch or right-click > Auto merge): a polygon you draw, rectangle or copy that overlaps or touches another polygon is merged with it into one (one Ctrl+Z undoes both); refused when it only touches at a corner or would leave a hole. Merge tolerance (right-click menu; pick the unit with the unit button, default 0, max 50 cm) also joins shapes that are that close.
Toolbar: tools that do not fit move into the More (...) menu at its right end. More > Customize toolbar (or right-click > Customize toolbar) lets you show, hide and reorder tools (drag, or the arrow buttons); hidden tools still work from the right-click menu and their keys. Saved in this browser.
| D | Draw an outline: click corners, click the first point (3+ corners), double-click or Enter finishes, Backspace undoes a corner, Esc cancels. Shift = 45-degree steps, Ctrl = no snapping. |
| A | Rectangle: click two corners, pull to the width, click. |
| Click | Click a polygon to edit it: drag corners, drag a midpoint to add a corner, drag the move handle (four arrows) to move it, the rotate handle (circular arrow) to rotate it (hold Shift to snap to the step set in Settings). Enter or Esc finishes; Delete removes it. |
| E | Extrude / indent: edit a polygon, click two points on a side, pull, click. |
| X | Slice: click a line across a polygon (the edited one, or every polygon the line splits when none is edited), Enter or double-click slices. Rays (I) extend the line endlessly. |
| C | Carve: click the corners of a shape, Enter or double-click removes it from every polygon it overlaps (it must reach a polygon's edge). |
| Q | Copy an outline (also the toolbar Copy button and right-click menu): hover a City footprint (needs the layer on); the nearest edge within 10 px wins, else the smallest outline around the cursor; it lights up white; click copies it as a polygon opened for editing. Esc cancels. |
| G | Merge: click one polygon, Ctrl+click others, press G (or right-click > Merge). |
| Sides | Click a side, Ctrl+click more, Ctrl+drag lasso (Alt removes); drag to move them. |
| Align sides | Select sides, set a reference line, right-click > Align sides to reference line: each side turns about its middle to parallel or perpendicular, whichever is closer. |
| Right-click | Menu: square / round corners, extrude, slice, carve, merge, reference line. |
| L P | Open Google Maps, Pictometry (Assessor Beacon) for the polygon being edited, else the map centre. Opens a new window; nothing is embedded. |
| W | Hide / show your outlines. |
| Esc | Esc (when nothing is selected): hide or show the reference line. |
| I J | Guide rays on / off; lock the ray direction (Esc unlocks). |
| Ctrl+Z | Undo (Ctrl+Y or Ctrl+Shift+Z redo). |
| Arrows | While editing: nudge by the step set in Settings (Shift: 5 times that), only the selected corner if one is selected (click it); [ ] rotate 0.5 degree. |