I would like to know how can I manage multiple legends with heatmap_legend_param ? 

My annotations looks like

head(colData)

      purity Center Year  BMI Gender
sample1     75 Geneva 2011   20     F
sample2    90 Milano 2011 <NA>      F
sample3    90  Lille 2011   30      M
sample4    80  Lille 2012   20      M
sample5    95  Miami 2011 <NA>      M
sample6    60 Geneva 2013   30      M

ha = HeatmapAnnotation(df = colData, show_annotation_name=TRUE)

ht1 <- Heatmap(x, top_annotation=ha, cluster_rows=FALSE, cluster_columns=FALSE, col = colorRamp2(c(-3, 0, 3), c("green", "black", "red")), show_row_names=FALSE,  heatmap_legend_param = list(color_bar = "continuous", legend_direction = "horizontal", legend_width = unit(5, "cm"), title_position = "lefttop"))

draw(ht1, heatmap_legend_side = "bottom")​

Here only the first legend gets printed at the bottom, but I would like to place all the legends either at the bottom or top as they do not fit properly on the right side.

I understood that the heatmap_legend_param is only for the heatmap and I need to use annotation_legend_param and I can specify nrow and ncol to get the desired format and then I can place them at the bottom using annotation_legend_side = "bottom"