st1 = (b[0] - 25) * (b[0] - 25) + (b[1] - 25) * (b[1] - 25);

                    return dist0 - dist1;
                });

                function renderItem(params, api) {
                    var context = params.context;
                    var lngIndex = api.value(0);
                    var latIndex = api.value(1);
                    var coordLeftTop = [
                        +(latExtent[0] + lngIndex * cellSizeCoord[0]).toFixed(6),
                        +(lngExtent[0] + latIndex * cellSizeCoord