Skip to content

Instantly share code, notes, and snippets.

@ThomasG77

ThomasG77/index.html

Last active January 27, 2018 21:51
Show Gist options
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save ThomasG77/00d60bd321570521c2bf03649280c336 to your computer and use it in GitHub Desktop.
Save ThomasG77/00d60bd321570521c2bf03649280c336 to your computer and use it in GitHub Desktop.
Download ZIP
Constrainted drawing within another layer area with OpenLayers (based on official Measure example)
Raw
index.html
<!DOCTYPE html>
<html>
<head>
<title>Constrainted drawing (based on official Measure example)</title>
<link rel="stylesheet" href="https://openlayers.org/en/v4.6.4/css/ol.css" type="text/css">
<script src='https://npmcdn.com/@turf/turf/turf.min.js'></script>
<!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
<script src="https://openlayers.org/en/v4.6.4/build/ol.js"></script>
<style>
.tooltip {
position: relative;
background: rgba(0, 0, 0, 0.5);
border-radius: 4px;
color: white;
padding: 4px 8px;
opacity: 0.7;
white-space: nowrap;
}
.hidden {
display: none;
}
.tooltip-measure {
opacity: 1;
font-weight: bold;
}
.tooltip-static {
background-color: #ffcc33;
color: black;
border: 1px solid white;
}
.tooltip-measure:before,
.tooltip-static:before {
border-top: 6px solid rgba(0, 0, 0, 0.5);
border-right: 6px solid transparent;
border-left: 6px solid transparent;
content: "";
position: absolute;
bottom: -6px;
margin-left: -7px;
left: 50%;
}
.tooltip-static:before {
border-top-color: #ffcc33;
} </style>
</head>
<body>
<div id="map" class="map"></div>
<form class="form-inline">
<input id="checkBox" type="checkbox" checked>
<label>Activate polygon drawing</label>
</form>
<script>
var raster = new ol.layer.Tile({
source: new ol.source.OSM()
});
var contour = {
"type": "FeatureCollection",
"features": [{
"type": "Feature",
"geometry": {
"type": "Polygon",
"coordinates": [[[-98.82127046585083,38.13872527585437],[-98.8250470161438,38.1400416575801],[-98.8253903388977,38.14351814128884],[-98.82702112197876,38.140851726838264],[-98.83294343948364,38.144159416303694],[-98.83071184158325,38.14858068536492],[-98.82543325424194,38.151314313084185],[-98.82629156112671,38.14507069215483],[-98.82019758224487,38.1480069480217],[-98.81491899490356,38.15323791562108],[-98.8102412223816,38.15273170934594],[-98.8080096244812,38.150808093458124],[-98.80461931228638,38.15185427681277],[-98.80011320114136,38.15020062526921],[-98.79955530166626,38.14571195352295],[-98.80303144454956,38.14226932639963],[-98.81191492080688,38.143079370925676],[-98.81393194198608,38.13808395307731],[-98.82127046585083,38.13872527585437]]]
},
"properties": {}
}]
};
var rewindedPolygons = turf.rewind(contour);
var geoJSONSource = new ol.source.Vector({
features: new ol.format.GeoJSON({
featureProjection: 'EPSG:3857'
}).readFeatures(rewindedPolygons)
});
var vectorRestrictionLayer = new ol.layer.Vector({
source: geoJSONSource,
style: new ol.style.Style({
fill: new ol.style.Fill({
color: 'red'
})
})
});
var conditionNoModifierKeysWithin = function(mapBrowserEvent) {
var drawWithin = rewindedPolygons.features.some(feat => {
return turf.booleanPointInPolygon(
ol.proj.toLonLat(mapBrowserEvent.coordinate),
feat
);
});
var originalEvent = mapBrowserEvent.originalEvent;
return (
!originalEvent.altKey &&
!(originalEvent.metaKey || originalEvent.ctrlKey) &&
!originalEvent.shiftKey && drawWithin);
};
var source = new ol.source.Vector();
var vector = new ol.layer.Vector({
source: source,
style: new ol.style.Style({
fill: new ol.style.Fill({
color: 'rgba(255, 255, 255, 0.2)'
}),
stroke: new ol.style.Stroke({
color: '#ffcc33',
width: 2
}),
image: new ol.style.Circle({
radius: 7,
fill: new ol.style.Fill({
color: '#ffcc33'
})
})
})
});
/**
* Currently drawn feature.
* @type {ol.Feature}
*/
var sketch;
/**
* The help tooltip element.
* @type {Element}
*/
var helpTooltipElement;
/**
* Overlay to show the help messages.
* @type {ol.Overlay}
*/
var helpTooltip;
/**
* The measure tooltip element.
* @type {Element}
*/
var measureTooltipElement;
/**
* Overlay to show the measurement.
* @type {ol.Overlay}
*/
var measureTooltip;
/**
* Message to show when the user is drawing a polygon.
* @type {string}
*/
var continuePolygonMsg = 'Click to continue drawing the polygon';
var avoidDrawingHere = 'You are outside the allowed area to draw';
/**
* Handle pointer move.
* @param {ol.MapBrowserEvent} evt The event.
*/
var pointerMoveHandler = function(evt) {
if (evt.dragging) {
return;
}
/** @type {string} */
var helpMsg = 'Click to start drawing';
if (sketch) {
var geom = (sketch.getGeometry());
var withinSketched = turf.booleanPointInPolygon(ol.proj.toLonLat(evt.coordinate), rewindedPolygons.features[0]);
if (withinSketched) {
helpMsg = continuePolygonMsg;
} else {
helpMsg = avoidDrawingHere;
}
} else {
var within = rewindedPolygons.features.some(feat => {
return turf.booleanPointInPolygon(
ol.proj.toLonLat(evt.coordinate),
feat
);
});
if (!within) {
helpMsg = 'You are not allowed to start drawing from here'
}
}
helpTooltipElement.innerHTML = helpMsg;
helpTooltip.setPosition(evt.coordinate);
helpTooltipElement.classList.remove('hidden');
};
var map = new ol.Map({
layers: [raster, vectorRestrictionLayer, vector],
target: 'map',
view: new ol.View({
center: [-11000000, 4600000],
zoom: 16
})
});
var key;
key = map.on('pointermove', pointerMoveHandler);
// ol.Observable.unByKey(key);
map.getViewport().addEventListener('mouseout', function() {
helpTooltipElement.classList.add('hidden');
});
var draw; // global so we can remove it later
/**
* Format area output.
* @param {ol.geom.Polygon} polygon The polygon.
* @return {string} Formatted area.
*/
var formatArea = function(polygon) {
var area = ol.Sphere.getArea(polygon);
var output;
if (area > 10000) {
output = (Math.round(area / 1000000 * 100) / 100) +
' ' + 'km<sup>2</sup>';
} else {
output = (Math.round(area * 100) / 100) +
' ' + 'm<sup>2</sup>';
}
return output;
};
function addInteraction() {
var type = 'Polygon';
draw = new ol.interaction.Draw({
condition: conditionNoModifierKeysWithin,
source: source,
type: type,
style: new ol.style.Style({
fill: new ol.style.Fill({
color: 'rgba(255, 255, 255, 0.2)'
}),
stroke: new ol.style.Stroke({
color: 'rgba(0, 0, 0, 0.5)',
lineDash: [10, 10],
width: 2
}),
image: new ol.style.Circle({
radius: 5,
stroke: new ol.style.Stroke({
color: 'rgba(0, 0, 0, 0.7)'
}),
fill: new ol.style.Fill({
color: 'rgba(255, 255, 255, 0.2)'
})
})
})
});
map.addInteraction(draw);
createMeasureTooltip();
createHelpTooltip();
var listener;
draw.on('drawstart',
function(evt) {
// set sketch
sketch = evt.feature;
/** @type {ol.Coordinate|undefined} */
var tooltipCoord = evt.coordinate;
listener = sketch.getGeometry().on('change', function(evt) {
var geom = evt.target;
var output = formatArea(geom);
tooltipCoord = geom.getInteriorPoint().getCoordinates();
measureTooltipElement.innerHTML = output;
measureTooltip.setPosition(tooltipCoord);
});
}, this);
draw.on('drawend',
function() {
measureTooltipElement.className = 'tooltip tooltip-static';
measureTooltip.setOffset([0, -7]);
// unset sketch
sketch = null;
// unset tooltip so that a new one can be created
measureTooltipElement = null;
createMeasureTooltip();
ol.Observable.unByKey(listener);
}, this);
}
/**
* Creates a new help tooltip
*/
function createHelpTooltip() {
if (helpTooltipElement) {
helpTooltipElement.parentNode.removeChild(helpTooltipElement);
}
helpTooltipElement = document.createElement('div');
helpTooltipElement.className = 'tooltip hidden';
helpTooltip = new ol.Overlay({
element: helpTooltipElement,
offset: [15, 0],
positioning: 'center-left'
});
map.addOverlay(helpTooltip);
}
/**
* Creates a new measure tooltip
*/
function createMeasureTooltip() {
if (measureTooltipElement) {
measureTooltipElement.parentNode.removeChild(measureTooltipElement);
}
measureTooltipElement = document.createElement('div');
measureTooltipElement.className = 'tooltip tooltip-measure';
measureTooltip = new ol.Overlay({
element: measureTooltipElement,
offset: [0, -15],
positioning: 'bottom-center'
});
map.addOverlay(measureTooltip);
}
/**
* Let user change the geometry type.
*/
var checkBox = document.getElementById('checkBox');
checkBox.addEventListener('click', function(e) {
if (this.checked) {
map.removeInteraction(draw);
addInteraction();
helpTooltipElement.classList.remove('hidden');
if (Object.keys(key).length === 0) {
key = map.on('pointermove', pointerMoveHandler);
}
} else {
map.removeInteraction(draw);
ol.Observable.unByKey(key);
}
});
addInteraction();
</script>
</body>
</html>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment