Edit: bug report here
I am trying to display images on maps. For the example, let's say I want tomake a map with regions and their coats of arms. There is a simple example below.
The text appears (Vega-Lite editor) but the images only appear with the x and y channels, not with latitude and longitude.
Is this about me, about a known limitation, or about a bug?
Linked question: is it possible to use SVG files rather than PNG ?
{
"config": {"view": {"continuousWidth": 300, "continuousHeight": 400}},
"layer": [
{
"mark": {"type": "text", "font": "Ubuntu", "fontSize": 18},
"encoding": {
"latitude": {"field": "latitude", "type": "quantitative"},
"longitude": {"field": "longitude", "type": "quantitative"},
"text": {"type": "nominal", "field": "name"}
}
},
{
"mark": {"type": "image", "height": 50, "width": 50},
"encoding": {
"latitude": {"field": "latitude", "type": "quantitative"},
"longitude": {"field": "longitude", "type": "quantitative"},
"url": {"type": "nominal", "field": "url"}
}
}
],
"data": {"name": "data"},
"$schema": "https://vega.github.io/schema/vega-lite/v5.0.0.json",
"datasets": {
"data": [
{
"name": "Unterfranken",
"wikidata": "Q10547",
"latitude": 50.011166583816824,
"longitude": 9.94760069351192,
"url": "https://upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Unterfranken_Wappen.svg/512px-Unterfranken_Wappen.svg.png"
},
{
"name": "Oberfranken",
"wikidata": "Q10554",
"latitude": 50.05097220003501,
"longitude": 11.376017810598547,
"url": "https://upload.wikimedia.org/wikipedia/commons/thumb/0/06/Wappen_Bezirk_Oberfranken2.svg/500px-Wappen_Bezirk_Oberfranken2.svg.png"
},
{
"name": "Niederbayern",
"wikidata": "Q10559",
"latitude": 48.70663162458262,
"longitude": 12.78636846158091,
"url": "https://upload.wikimedia.org/wikipedia/commons/thumb/7/78/Wappen_Bezirk_Niederbayern.svg/352px-Wappen_Bezirk_Niederbayern.svg.png"
},
{
"name": "Oberpfalz",
"wikidata": "Q10555",
"latitude": 49.399491050485366,
"longitude": 12.117024154659765,
"url": "https://upload.wikimedia.org/wikipedia/commons/thumb/1/18/Wappen_Oberpfalz.svg/177px-Wappen_Oberpfalz.svg.png"
},
{
"name": "Mittelfranken",
"wikidata": "Q10551",
"latitude": 49.348122683559716,
"longitude": 10.786147287006969,
"url": "https://upload.wikimedia.org/wikipedia/commons/thumb/8/8d/Mittelfranken_Wappen.svg/393px-Mittelfranken_Wappen.svg.png"
},
{
"name": "Schwaben",
"wikidata": "Q10557",
"latitude": 48.1625551901062,
"longitude": 10.519367235613796,
"url": "https://upload.wikimedia.org/wikipedia/commons/thumb/5/55/Wappen_Schwaben_Bayern.svg/450px-Wappen_Schwaben_Bayern.svg.png"
},
{
"name": "Oberbayern",
"wikidata": "Q10562",
"latitude": 48.10116954364846,
"longitude": 11.753750582859597,
"url": "https://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Wappen_Oberbayern.svg/200px-Wappen_Oberbayern.svg.png"
}
]
}
}
This feature does not yet exist but will be added in future versions of Vega-Lite/Altair as per this PR https://github.com/vega/vega-lite/pull/7296.