A custom mode for MapboxGL-Draw to split polygons based on a drawn lineString.
Check mapbox-gl-draw-split-line-mode For splitting lineStrings.
npm install mapbox-gl-draw-split-polygon-mode
or use CDN:
<script src="https://unpkg.com/mapbox-gl-draw-split-polygon-mode"></script>
import mapboxGl from "mapbox-gl";
import MapboxDraw from "@mapbox/mapbox-gl-draw";
import SplitPolygonMode, {
drawStyles as splitPolygonDrawStyles,
} from "mapbox-gl-draw-split-polygon-mode";
const map = new mapboxgl.Map({
container: "map",
center: [-91.874, 42.76],
zoom: 12,
});
draw = new MapboxDraw({
userProperties: true,
displayControlsDefault: false,
modes: {
...SplitPolygonMode(MapboxDraw.modes),
},
styles: [...splitPolygonDrawStyles(MapboxDraw.lib.theme)],
userProperties: true,
});
map.addControl(draw);
/// Activate the mode
draw.changeMode("split_polygon");
/// you can modify the behavior using these options:
draw.changeMode(
"split_polygon",
/** Default option values: */
{
highlightColor: "#222",
lineWidth: 0,
lineWidthUnit: "kilometers",
}
);
The syntax used here is because
mapbox-gl-draw-split-polygon-mode
needs to modify the modes object and also thestyles
object passed to themapbox-gl-draw
. the reason is this package usesmapbox-gl-draw-passing-mode
underneath (and adds this to modes object) and needs to modify the styles to show the selected feature.
also, take a look at the example in the demo
directory. in this example mapbox-gl-draw-select-mode
is used so users can select feature after clicking in the split icon in the toolbar and get a highlighting when hover each map feature.
Splitting polygons are done using the polygon-splitter
package. which is pretty neat but has some issues and quirks. if you specify a lineWidth
option other than zero (0)
another algorithm is used which doesn't have those issues but creates a spacing between features so they can no longer become union
.
Also, There is an issue in mapbox-gl-draw
which causes multi-features to have the same properties object and therefor if you uncombine
a multi-feature and try to split one of the pieces the whole multi-feature gets highlighted as the selected feature.
import mapboxGl from 'mapbox-gl';
import MapboxDraw from '@mapbox/mapbox-gl-draw';
+ import defaultDrawStyle from "https://unpkg.com/@mapbox/mapbox-gl-draw@1.3.0/src/lib/theme.js";
- import SplitPolygonMode from 'mapbox-gl-draw-split-polygon-mode';
- import mapboxGlDrawPassingMode from 'mapbox-gl-draw-passing-mode';
+ import SplitPolygonMode, {
+ drawStyles as splitPolygonDrawStyles,
+ } from "mapbox-gl-draw-split-polygon-mode";
draw = new MapboxDraw({
- modes: Object.assign(MapboxDraw.modes, {
- splitPolygonMode: SplitPolygonMode,
- passing_mode_line_string: mapboxGlDrawPassingMode(
- MapboxDraw.modes.draw_line_string
- ),
- }),
+ modes: {
+ ...SplitPolygonMode(MapboxDraw.modes),
+ },
+ styles: [...splitPolygonDrawStyles(defaultDrawStyle)],
userProperties: true,
});
- draw.changeMode('splitPolygonMode');
+ draw.changeMode("split_polygon");
use the command npm run dev
. it will take advantage of vite
to watch, serve, and build the package and the demo.
The main function responsible for cutting the features is from: https://gis.stackexchange.com/a/344277/145409
MIT © ReyhaneMasumi