Usage Guide
How the GeoCanvas workspace is laid out, and what each panel does.
The workspace
Three surfaces surround the map: the projection panel, the map bar and the tabbed panel. On a wide screen the two panels sit either side of the map and the bar floats along the bottom; either panel collapses with the chevron in its header to give the map more room. On a phone the same panels share one sheet you pull up over the map, and the bar is a fixed row above it.
Projections
- Every projection GeoCanvas can draw, grouped by family: cylindrical, pseudocylindrical, conic, azimuthal, pseudoconic, polyconic, polyhedral and other.
- The chips at the top narrow the list to one family. All brings the whole catalogue back.
- Each row shows a thumbnail of the graticule and the projection's property: conformal, equal area, equidistant or compromise.
- Picking a projection redraws every layer on it immediately. Nothing is lost in the switch.
- The i button on the selected row opens that projection's own page inside the panel.
- Random at the foot of the panel jumps to an arbitrary projection.
Projection settings
Opening a projection's page turns the panel into its settings. The λ φ γ readout is a shortcut to the same place — in the map bar on a wide screen, in the top bar on a phone.
- About: a short description, the property, who invented it and when, and what it is normally used for.
- Orientation: λ centre, φ centre and γ roll turn the globe underneath the projection — recentre the map, swap north for south, or tilt the whole frame.
- Parameters: shown only for projections that have any, such as the number of lobes on Berghaus or the standard parallel on Peters.
- usage.projectionSettings.list.performance
- Reset orientation returns λ, φ and γ to zero.
Map bar (bottom)
The map bar has two modes, Navigate and Draw, and each offers a different set of tools. A switch at the start of the bar moves between them; on a phone it is a single slanted control naming the mode you are in.
NavigateMode
One tool is active at a time; click another to switch.
Move
Drag the map to a different position on the canvas.
Rotate
Drag to turn the globe under the projection, changing the centre of the map or swapping north and south. The λ φ γ readout beside the tools opens the orientation sliders for exact degrees, including the roll axis.
Select
Click or tap a feature to pick it up in the Features panel. With a mouse, a second button appears while Select is active, which highlights whichever feature is under the pointer as you move it.
Zoom
On a wide screen the − and + buttons step the zoom, and the percentage between them is measured against the projection fitted to the canvas. A phone shows the percentage on its own and zooms by pinch. The mouse wheel zooms everywhere.
Timeline
Shows and hides the time slider, and stays greyed out until a layer on the map has a time axis. On a phone it lives in the More menu rather than the toolbar.
Reset
Returns rotation, position and zoom to their defaults.
DrawMode
Draw mode edits one editable layer. Create one with Upload file or Draw new in the Edit tab, or copy a catalogue layer to an editable one from the Layers tab.
Lines
Line, polyline and path. The chevron beside the button chooses which of them the button draws.
Shapes
Circle, rectangle, ellipse and triangle, again picked through the chevron beside the button.
Polygon
Click a corner at a time to trace a free-form outline.
Text
Place a point carrying a label.
Erase
Remove features from the layer you are editing.
More tools
The last chevron holds the remaining drawing tools.
Layers, style and export
Five panels hold the rest: Layers, Visual Tools, Export, Edit and Features. On a wide screen they are tabs along the top of the right panel, and the arrow at the end of the strip reaches any that do not fit. On a phone they are destinations in the bar along the bottom, with the last few behind More.
Layers
Active layers lists everything on the map, with a count on the right of how many there are and how many are visible.
Each card carries the controls for its layer:
- The eye switches the layer on and off.
- The button beside it opens symbology — how the layer is drawn — and the swatch next to that sets its colour.
- The chip on the right names the kind of layer: Cultural, Physical, Raster and so on.
- The chevron expands the card for opacity and resolution, the layer's identity and where it came from, and buttons to duplicate it or copy it to an editable layer.
- Drag a card by its grip to restack. Layers draw bottom-up, exactly as listed, so a layer meant to cover the others belongs at the bottom.
- The bin removes the layer. Careful: removing an editable layer deletes the features drawn on it.
Favorites underneath is a short list of useful layers, each with an Add button; the pin keeps one on the list. Open Data leads to the full catalogue, and a WMS or WMTS service can be connected from the same two lines.
At the foot, Import layer takes a file from your machine and Catalogue opens everything available.
Visual Tools
Overlays that explain the map rather than add data to it. Every row has a switch, and its chevron opens the tool's own options. Turn all off at the foot clears the lot.
- Boundary — Projection Outline draws the edge of the projection.
- Grid — Graticule and Graticule Labels, plus Tiles, which shows how a raster tile pyramid would fall on the projection.
- Reference — Equator & Tropics, Scale Bar and Time Zones.
- Routing — Great Circle Route draws the shortest path between two points you pick; Rhumb Line draws the constant-bearing path between them instead.
- Analysis — Distance Circles around a chosen point, Antipodes, and the Tissot Indicatrix, whose circles show how the projection distorts.
- Earth Physics — Magnetic Declination, setting the magnetic poles against the geomagnetic ones for a year you choose, and Gravity, showing how real gravity strength grows toward the poles.
- Celestial — Sun Position with its day and night terminator, and Moon Position. Both run off the same clock, which can be moved through time.
Export
Saves the map as an image or as data, and saves the project itself.
- PNG: raster, lossless, keeps transparency.
- JPEG: raster, compressed, smaller files.
- SVG: vector, editable in a drawing program.
- GeoJSON: the features themselves, with their properties.
Size offers presets — screen, 2×, 4×, A4 and A3 at 300 dpi, 4K — or your own width and height, with a lock to hold the aspect ratio. Large exports are rendered in tiles and stitched back together so the detail matches the map on screen.
A transparent background and the file name sit below that, and the button under them runs the export.
Project Management at the foot writes the whole map to a project file and loads one back.
Edit
Where an editable layer is built and styled. Start one with Upload file or Draw new, or copy a catalogue layer across from the Layers tab. Picking a layer opens its sections:
- Symbology: how the layer is drawn, including styling by the value of an attribute.
- Labels: which field is written on the map, and how.
- Legend: a legend for the layer, drawn onto the map.
- Features: the features on the layer, one by one.
- Geometry: draw, edit, clip and simplify.
- Data: the attribute fields.
- Layer info: its name, its id, and where it came from.
The back arrow in the heading returns to the list of editable layers. More advanced work is covered on the Editing page.
Features
Switch the map bar to Select and click a feature to collect it here. The header counts the selection, and the line above the list says how many of them are currently in view.
- Chevron: opens the feature's properties.
- Dot: filled while the feature is inside the viewport, hollow when it has scrolled off.
- Crosshair: moves the map to the feature.
- ×: drops the feature from the selection. It deletes nothing.
Available Features below counts what each layer has in the current viewport and lets you reach them without clicking the map. Clear selection empties the list.
