cardinal snap for map editing page

[brendanheywood]

The new editing page is pretty awesome. However it does not have snapping which makes it much harder to nicely line up adjacent areas.

There should be 2 types of snapping:

1. snapping onto any other lines or vertexs from other area. This one is out of the box with open layers and should be trivial to add:

https://openlayers.org/en/latest/examples/snap.html

This one is much better than the one which was part of the old maps which only did vertex snapping and not line snapping.

2. cardinal snapping east west north south so you can easily make a perfect rectangle. This only needs to snap to vertices in the current shape not other shapes. This makes a big different in making maps look tidy otherwise everything is free form and irregular.

import Draw from 'ol/interaction/Draw';

const draw = new Draw({
  source: vectorSource,
  type: 'LineString',
  geometryFunction: function (coords, geom) {
    if (!geom) {
      geom = new ol.geom.LineString(null);
    }

    if (coords.length > 1) {
      const last = coords[coords.length - 2];
      const curr = coords[coords.length - 1];

      const dx = Math.abs(curr[0] - last[0]);
      const dy = Math.abs(curr[1] - last[1]);

      // snap horizontally or vertically
      if (dx > dy) {
        curr[1] = last[1]; // horizontal
      } else {
        curr[0] = last[0]; // vertical
      }
    }

    geom.setCoordinates(coords);
    return geom;
  }
});

map.addInteraction(draw);

[nicHoch]

The first snapping is in place and it is working for me.
Can you send an example where it is not working for you?

[brendanheywood]

Ah you are right, the problem is that it wasn't snapping to itself so I assumed that was not snapping to anything. So for example if you draw a box, then click on a side to insert a new point and then drag that point around then it doesn't snap to the existing line it is already part of. The snapping here by comparison does do this:
https://openlayers.org/en/latest/examples/snap.html

Another 2 things I've notice with the new maps:

1. The navigate vs 'draw / edit' buttons no longer highlight to show you which mode you are in.

They both always have the 'active' class but only 1 should at a time so it looks like this:

2. another little annoyance is when you edit a region it is zoomed too tightly on it by default, it should have a little margin:

https://www.thecrag.com/climbing/australia/gara-gorge/upper-gara-gorge/area/13055166723/locate

[brendanheywood]

And one more little thing, the default map should be satellite. OSM is completely useless for locating anything natural, for the same reason that in the normal view OSM is the default at the region level as it is good for towns and roads, but it defaults to satellite when zoomed in.

So I think the maps page should either use the same logic as the view maps when picking a default, or it should always default to satellite if its hard to reuse that logic.

[nicHoch]

• active edit / nav
• margin
• snap to other borders
• snap to self - Won't fix:
• cardinal snap
• default satellite - Won't fix: will stay OSM as >95% of the users will see only OSM