anychart.onDocumentReady(function () {
var chart = anychart.line([
{x: 'January', value: 200},
{x: 'February', value: 500},
{x: 'March', value: 300},
{x: 'April', value: 900},
chart.yScale(anychart.scales.log());
chart.title('Trying to get a tick position');
chart.container('container');
var logScale = chart.yScale();
var position = logScale.inverseTransform(0.5);
chart.lineMarker({value: position});