<MapView
        provider={PROVIDER_GOOGLE}
        style={{ flex: 1 }}
        region={{
          latitude: 41.20060,
          longitude: 47.18932,
          latitudeDelta: 0.0922,
          longitudeDelta: 0.0421
        }}
      >
        <Consumer>
          {value => {
            const { heritages } = value;
            return (
              <React.Fragment>
                {
                  heritages.slice(0, 251).filter(h => h.x !== '' && h.y !== '').map(h =>
                    <MapDetail key={h.id} title={h.ad_az} x={h.x} y={h.y} category={h.category} />
                  )
                }
              </React.Fragment>
            );
          }}
        </Consumer>
      </MapView>