Vega Zoomable USA Map - vega

Question

I want to use this map https://vega.github.io/vega/examples/zoomable-world-map/ but only for USA.
I used this spec.
private specVega = {
"$schema": "https://vega.github.io/schema/vega/v5.json",
"description": "An interactive world map supporting pan and zoom.",
"width": 900,
"height": 500,
"autosize": "none",
"signals": [
{ "name": "tx", "update": "width / 2" },
{ "name": "ty", "update": "height / 2" },
{
"name": "scale",
"value": 150,
"on": [{
"events": {"type": "wheel", "consume": true},
"update": "clamp(scale * pow(1.0005, -event.deltaY * pow(16, event.deltaMode)), 150, 3000)"
}]
},
{
"name": "angles",
"value": [0, 0],
"on": [{
"events": "mousedown",
"update": "[rotateX, centerY]"
}]
},
{
"name": "cloned",
"value": null,
"on": [{
"events": "mousedown",
"update": "copy('projection')"
}]
},
{
"name": "start",
"value": null,
"on": [{
"events": "mousedown",
"update": "invert(cloned, xy())"
}]
},
{
"name": "drag", "value": null,
"on": [{
"events": "[mousedown, window:mouseup] > window:mousemove",
"update": "invert(cloned, xy())"
}]
},
{
"name": "delta", "value": null,
"on": [{
"events": {"signal": "drag"},
"update": "[drag[0] - start[0], start[1] - drag[1]]"
}]
},
{
"name": "rotateX", "value": 0,
"on": [{
"events": {"signal": "delta"},
"update": "angles[0] + delta[0]"
}]
},
{
"name": "centerY", "value": 0,
"on": [{
"events": {"signal": "delta"},
"update": "clamp(angles[1] + delta[1], -60, 60)"
}]
}
],
"projections": [
{
"name": "projection",
"type": "mercator",
"scale": {"signal": "scale"},
"rotate": [{"signal": "rotateX"}, 0, 0],
"center": [0, {"signal": "centerY"}],
"translate": [{"signal": "tx"}, {"signal": "ty"}]
}
],
"data": [
{
"name": "counties",
values: null,
"format": {"type": "topojson", "feature": "states"},
},
{
"name": "graticule",
"transform": [
{ "type": "graticule", "step": [15, 15] }
]
}
],
"marks": [
{
"type": "shape",
"from": {"data": "graticule"},
"encode": {
"enter": {
"strokeWidth": {"value": 1},
"stroke": {"value": "#ddd"},
"fill": {"value": null}
}
},
"transform": [
{ "type": "geoshape", "projection": "projection" }
]
},
{
"type": "shape",
"from": {"data": "states"},
"encode": {
"enter": {
"strokeWidth": {"value": 0.5},
"stroke": {"value": "#bbb"},
"fill": {"value": "#e5e8d3"}
}
},
"transform": [
{ "type": "geoshape", "projection": "projection" }
]
}
]
}
this.specVega["data"][0]["values"] = "data/us-10m.json" (this is just for understanding which data i used)
So i put data for only US here, but it didn't work. Got an error in console:
Undefined data set name: "states"
In general i just need a zoomable map for USA only, which i am going to use as a bubble map.
If this map has a zoom i would definitely use it https://vega.github.io/vega-lite/examples/geo_layer.html

Answer 1

Here is an working example of USA map by states or counties in "albersUsa" projection. Zooming is by mouse wheel and panning by mouse click-drag. For better performance, zooming and panning are best done with states instead of counties.
View in Vega online editor
{
"$schema": "https://vega.github.io/schema/vega/v5.json",
"description": "An interactive USA map supporting pan and zoom.",
"width": 900,
"height": 500,
"autosize": "none",
"signals": [
{
"name": "signal_show_map_graticule",
"value": true,
"bind": {
"input": "checkbox",
"name": "Map graticule: "}
},
{
"name": "signal_states_or_counties",
"value": "states",
"bind": { "input": "select",
"options": ["states", "counties"],
"name": "Map areas: "
}
},
{
"name": "signal_map_scale",
"value": 1000,
"bind": {"input": "range", "min": 1000, "max": 4000, "step": 50, "name": "Map scale: "},
"on": [{
"events": {"type": "wheel", "consume": true},
"update": "round(clamp(signal_map_scale * pow(1.0005, -event.deltaY * pow(16, event.deltaMode)), 1000, 4000))"
}]
},
{ "name": "signal_translate_xy",
"value": [450, 250],
"update": "[clamp(signal_translate_last_xy[0] + signal_mouse_delta_xy[0], -300, 1200), clamp(signal_translate_last_xy[1] + signal_mouse_delta_xy[1], -200, 800)]"
},
{ "name": "signal_translate_last_xy",
"value": [450, 250],
"on": [{
"events": [
{"type": "mousedown"}
],
"update": "signal_translate_xy"
}]
},
{
"name": "signal_mouse_start_xy",
"value": [0, 0],
"on": [{
"events": [
{"type": "mousedown"}
],
"update": "xy()"
}]
},
{
"name": "signal_mouse_drag_xy",
"value": [0, 0],
"on": [{
"events": [
{
"type": "mousemove",
"between": [
{"type": "mousedown"},
{"type": "mouseup"}
]
}
],
"update": "xy()"
}]
},
{
"name": "signal_mouse_delta_xy",
"value": [0, 0],
"update": "[signal_mouse_drag_xy[0] - signal_mouse_start_xy[0], signal_mouse_drag_xy[1] - signal_mouse_start_xy[1]]"
}
],
"projections": [
{
"name": "map_projection",
"type": "albersUsa",
"scale": {"signal": "signal_map_scale"},
"translate": {"signal": "signal_translate_xy"}
}
],
"data": [
{
"name": "data_geo_usa",
"url": "data/us-10m.json",
"format": {
"type": "topojson",
"feature": {"signal": "signal_states_or_counties"}
}
},
{
"name": "data_geo_graticule",
"transform": [
{ "type": "graticule", "step": [5, 5] }
]
}
],
"marks": [
{
"type": "shape",
"from": {"data": "data_geo_graticule"},
"encode": {
"enter": {
"strokeWidth": {"value": 1},
"stroke": {"value": "#ddd"}
},
"update": {
"strokeOpacity": {"signal": "signal_show_map_graticule ? 1 : 0"}
}
},
"transform": [
{ "type": "geoshape", "projection": "map_projection" }
]
},
{
"type": "shape",
"from": {"data": "data_geo_usa"},
"encode": {
"enter": {
"strokeWidth": {"value": 0.5},
"stroke": {"value": "#bbb"},
"fill": {"value": "#e5e8d3"}
}
},
"transform": [
{ "type": "geoshape", "projection": "map_projection" }
]
}
]
}

Answer 2

Change "data" to:
"data": [
{
"name": "states",
"url": "data/us-10m.json",
"format": {"type": "topojson", "feature": "states"}
},
View in Vega online editor

Answer 3

Apologies but I'm not a mapping expert. I have the following where zoom works fine but the drag is a little janky but definitely useable. It would probably take me quite a while to get this any better.
Roy's answer is another option for you.
{
"$schema": "https://vega.github.io/schema/vega/v5.json",
"autosize": "none",
"background": "white",
"padding": 5,
"width": 500,
"height": 300,
"signals": [
{"name": "tx", "update": "width / 2"},
{"name": "ty", "update": "height / 2"},
{
"name": "scale",
"value": 685,
"on": [
{
"events": {"type": "wheel", "consume": true},
"update": "clamp(scale * pow(1.0005, -event.deltaY * pow(16, event.deltaMode)), 150, 3000)"
}
]
},
{
"name": "angles",
"value": [222, 146],
"on": [{"events": "mousedown", "update": "[rotateX, centerY]"}]
},
{
"name": "cloned",
"value": null,
"on": [{"events": "mousedown", "update": "copy('projection')"}]
},
{
"name": "start",
"value": null,
"on": [{"events": "mousedown", "update": "invert(cloned, xy())"}]
},
{
"name": "drag",
"value": null,
"on": [
{
"events": "[mousedown, window:mouseup] > window:mousemove",
"update": "invert(cloned, xy())"
}
]
},
{
"name": "delta",
"value": null,
"on": [
{
"events": {"signal": "drag"},
"update": "[(drag[0] - start[0])*4, (start[1] - drag[1])*4]"
}
]
},
{
"name": "rotateX",
"value": 250,
"on": [{"events": {"signal": "delta"}, "update": "angles[0] + delta[0]"}]
},
{
"name": "centerY",
"value": 140,
"on": [{"events": {"signal": "delta"}, "update": "angles[1] + delta[1]"}]
}
],
"data": [
{
"name": "source_0",
"url": "data/us-10m.json",
"format": {"type": "topojson", "feature": "states"}
}
],
"projections": [
{
"name": "projection",
"scale": {"signal": "scale"},
"translate": [{"signal": "rotateX"}, {"signal": "centerY"}],
"type": "albersUsa"
}
],
"marks": [
{
"name": "marks",
"type": "shape",
"style": ["geoshape"],
"from": {"data": "source_0"},
"encode": {
"update": {"fill": {"value": "lightgray"}, "stroke": {"value": "white"}}
},
"transform": [{"type": "geoshape", "projection": "projection"}]
}
]
}