In my use case I need to create interactive farm maps where I can select fields. I'm trying to do this using the react-simple-maps component.
what was done
I created the farm Shapfile map in QGIS. Converted to TopoJSON using Mapshaper as per this tutorial.
However the map does not render correctly, see CodeSandbox.
What can I be missing?
Is this the best component to use in this case?
TopoJSON Map
{
"type": "Topology",
"arcs": [
[
[0, 62],
[51, 60],
[60, -46],
[-85, -76],
[-26, 62]
],
[
[112, 77],
[-60, 44],
[92, 110],
[57, -40],
[0, -2],
[-66, -60],
[14, -19],
[-37, -33]
]
],
"transform": {
"scale": [15.721852200470671, 19.17233904106825],
"translate": [-65942.30731638917, 8482615.288037943]
},
"objects": {
"Contorno_UTM": {
"type": "GeometryCollection",
"geometries": [
{
"arcs": [[0]],
"type": "Polygon",
"properties": { "id": 1, "area_ha": 197.4585 }
},
{
"arcs": [[1]],
"type": "Polygon",
"properties": { "id": 2, "area_ha": 299.0857 }
}
]
}
}
}
React Simple Map component
import React, { memo } from "react";
import {
ZoomableGroup,
ComposableMap,
Geographies,
Geography
} from "react-simple-maps";
import map from "./map.json";
const geoUrl = map;
const rounded = (num) => {
if (num > 1000000000) {
return Math.round(num / 100000000) / 10 + "Bn";
} else if (num > 1000000) {
return Math.round(num / 100000) / 10 + "M";
} else {
return Math.round(num / 100) / 10 + "K";
}
};
const MapChart = ({ setTooltipContent }) => {
return (
<>
<ComposableMap data-tip="" projectionConfig={{ scale: 200 }}>
<ZoomableGroup>
<Geographies geography={geoUrl}>
{({ geographies }) =>
geographies.map((geo) => (
<Geography
key={geo.rsmKey}
geography={geo}
onMouseEnter={() => {
const { id, area_ha } = geo.properties;
setTooltipContent(`${id} — ${rounded(area_ha)}`);
}}
onMouseLeave={() => {
setTooltipContent("");
}}
style={{
default: {
fill: "#D6D6DA",
outline: "none"
},
hover: {
fill: "#F53",
outline: "none"
},
pressed: {
fill: "#E42",
outline: "none"
}
}}
/>
))
}
</Geographies>
</ZoomableGroup>
</ComposableMap>
</>
);
};
export default memo(MapChart);
I managed to solve it, the problem was in the project's SRC configuration
, it was UTM
and the correct is WGS 84
, I changed, exported in GeoJSON
format and converted to TopoJSON
using Mapshaper, changed the projections and rotation and now everything is ok as you can see in CodeSandbox.
projection="geoAzimuthalEqualArea"
projectionConfig={{
rotate: [56.22, 13.66, 0],
scale: 360000
}}