labelingqgisstyle
I want to make my labels' size changed automatically with the scale of the map,so in the menu of "Layer labeling settings",I set the Text size" in map Unit".However,the labels in the selected layer disappeared.I turned off the "Scale-based visibility" and tried to set the size from 0.05 to 2000,but the labels still refused to meet me 😛 What should I do?
The points unit represents a constant size for the label on the screen, more or less the same as millimeters or pixels. Regardless of the map scale, a label of 10 points will be 10 points tall (let's ignore font sizing subtleties). It is your responsibility to hide the labels - or use a different size - beyond given map scales. For instance, labeling continents, you probably will keep the same size all the time, though if you label streets you will not want a size 10 label at any scale.
The map unit is the opposite. A label of size 1 (degree, meters, you name it) will always be of size 1 on the map, so the closer you are to scale 1:1 the bigger it is on your screen, and the more you zoom out the smaller the label is, still on your screen.
If you want finer control of a label that gets smaller as you zoom out and bigger as you zoom in, you would have to select the points unit, so the reference size is always the same on the screen, but you would also dynamically set the size in function of the scale, something like 10000000 /@map_scale (of course it depends on your data and you may want a non-linear scaling).
To answer you second question, you can instruct QGIS to hide labels that are not fully contained in their feature
...set the zoom level [...] from which [stuff] would be displayed on the map.
In Leaflet, you don't specify zoom levels for visibility and let Leaflet handle visibility (except for L.TileLayers), but rather the other way around: depending on the zoom level, you make something (in)visible by yourself.
The usual way to do this is reacting to zoomend events, e.g.:
var myMarker = L.marker([lat, lon]).addTo(map);
map.on('zoomend', function(ev){
if (map.getZoom() < 12) {
myMarker.addTo(map);
} else { // when zoom >= 12
myMarker.remove();
}
});
If you're using Leaflet.TextPath then you probably don't want to remove and addTo any L.Layers, but instead do something like
map.on('zoomend', function(ev){
if (map.getZoom() < 12) {
myPolyline.setText('something', {repeat: true});
} else { // when zoom >= 12
myPolyline.setText(null);
}
});
Best Answer
I also needed to specify the size label so I used the advice in a Comment on this Question:
You make labels smaller, entering the small figures due to 'Expression string builder' with scale.