mapchart 0.4.0 mapchart: ^0.4.0 copied to clipboard
Vector map chart for Flutter. Highly customizable. Compatible with GeoJSON. Pure Flutter.
Map Chart #
- Displays GeoJSON geometries
- Multi resolution with geometry simplification
- Highly customizable
- Interactable
- Pure Flutter (no WebView/JavaScript)
Get started #
A simplified GeoJSON will be used in the examples to demonstrate the different possibilities of themes. This GeoJSON has only 4 features with the following properties:
Name | Seq | Rnd |
---|---|---|
"Einstein" | 1 | "73" |
"Newton" | 2 | "92" |
"Galileu" | 3 | "10" |
"Darwin" | 4 | "52" |
"Pasteur" | 5 | "77" |
"Faraday" | 6 | "32" |
"Arquimedes" | 7 | "87" |
"Tesla" | 8 | "17" |
"Lavoisier" | 9 | "49" |
"Kepler" | 10 | "32" |
"Turing" | 11 | "93" |
To view the full content, use this link.
The following examples will assume that GeoJSON has already been loaded into a String.
Reading GeoJSON from String
No properties are loaded, only the geometries.
MapChartDataSource dataSource =
await MapChartDataSource.geoJSON(geojson: geojson);
Creating the Widget
MapChart map = MapChart(dataSource: dataSource);
Reading GeoJSON properties
The keys
argument defines which properties must be loaded.
The parseToNumber
argument defines which properties will have numeric values in quotes parsed to numbers.
MapChartDataSource dataSource = await MapChartDataSource.geoJSON(
geojson: geojson, keys: ['Seq', 'Rnd'], parseToNumber: ['Rnd']);
Changing the default colors #
MapChart map = MapChart(
dataSource: dataSource,
theme: MapChartTheme(
color: Colors.yellow,
contourColor: Colors.red,
hoverColor: Colors.orange));
Color by property value #
Sets a color for each property value in GeoJSON. If a color is not set, the default color is used.
Mapping the property key
MapChartDataSource dataSource =
await MapChartDataSource.geoJSON(geojson: geojson, keys: ['Seq']);
Setting the colors for the property values
MapChartTheme theme =
MapChartTheme.value(contourColor: Colors.white, key: 'Seq', colors: {
2: Colors.green,
4: Colors.red,
6: Colors.orange,
8: Colors.blue
}, hoverColors: {
2: Colors.green[900]!,
4: Colors.red[900]!,
6: Colors.orange[900]!,
8: Colors.blue[900]!
});
MapChart map = MapChart(dataSource: dataSource, theme: theme);
Color by rule #
The feature color is obtained from the first rule that returns a non-null color. If all rules return a null color, the default color is used.
Mapping the property key
MapChartDataSource dataSource = await MapChartDataSource.geoJSON(
geojson: geojson, keys: ['Name', 'Seq']);
Setting the rules
MapChartTheme theme = MapChartTheme.rule(
contourColor: Colors.white,
hoverColor: Colors.grey[700]!,
colorRules: [
(feature) {
String? value = feature.getValue('Name');
return value == 'Faraday' ? Colors.red : null;
},
(feature) {
double? value = feature.getDoubleValue('Seq');
return value != null && value < 3 ? Colors.green : null;
},
(feature) {
double? value = feature.getDoubleValue('Seq');
return value != null && value > 9 ? Colors.blue : null;
}
]);
MapChart map = MapChart(dataSource: dataSource, theme: theme);
Gradient #
The gradient is created given the colors and limit values of the chosen property. The property must have numeric values.
Auto min/max values
Uses the min and max values read from data source.
MapChartDataSource dataSource =
await MapChartDataSource.geoJSON(geojson: geojson, keys: ['Seq']);
MapChartTheme theme = MapChartTheme.gradient(
dataSource: dataSource,
contourColor: Colors.white,
key: 'Seq',
colors: [Colors.blue, Colors.yellow, Colors.red]);
MapChart map = MapChart(dataSource: dataSource, theme: theme);
Setting min or max values manually
If the min
value is set, all lower values will be displayed using the first gradient color.
If the max
value is set, all higher values will be displayed using the last gradient color.
MapChartDataSource dataSource =
await MapChartDataSource.geoJSON(geojson: geojson, keys: ['Seq']);
MapChartTheme theme = MapChartTheme.gradient(
contourColor: Colors.white,
key: 'Seq',
min: 3,
max: 9,
colors: [Colors.blue, Colors.yellow, Colors.red]);
MapChart map = MapChart(dataSource: dataSource, theme: theme);
Contour #
Thickness
MapChart map = MapChart(
dataSource: dataSource, theme: MapChartTheme(contourThickness: 3));
Hover contour color
MapChart map = MapChart(
dataSource: dataSource,
theme: MapChartTheme(hoverContourColor: Colors.red));
Hover #
Listener
MapChart map = MapChart(
dataSource: dataSource,
theme: MapChartTheme(hoverColor: Colors.grey[700]),
hoverListener: (MapFeature? feature) {
if (feature != null) {
int id = feature.id;
print('Hover - Feature id: $id');
}
});
Rule
Enabling hover by property value
MapChartDataSource dataSource =
await MapChartDataSource.geoJSON(geojson: geojson, keys: ['Seq']);
// coloring only the 'Darwin' feature
MapChartTheme theme = MapChartTheme.value(
key: 'Seq', colors: {4: Colors.green}, hoverColor: Colors.green[900]!);
// enabling hover only for the 'Darwin' feature
MapChart map = MapChart(
dataSource: dataSource,
theme: theme,
hoverRule: (feature) {
return feature.getValue('Seq') == 4;
},
);
Click listener #
MapChart map = MapChart(
dataSource: dataSource,
theme: MapChartTheme(hoverColor: Colors.grey[800]!),
clickListener: (feature) {
print(feature.id);
});
Agenda for the next few days #
- More theming features.
- Legend.
- Release the final version (1.0.0). The API may have some small changes.