plot_SBT_map <- function(plot_title="",lims=c(-170,170,-65,10),ht=8,wd=18,ofs=-50) {
  windows(width=wd,height=ht)
  plot(1,1, yaxt="n", xaxt="n", type="n", xlim=c(lims[1]+15,lims[2]-15), ylim=c(lims[3]+5,lims[4]-5), ylab="", xlab="", bg="lightblue")
  polygon(c(lims[1],lims[2],lims[2],lims[1]), c(lims[3],lims[3],lims[4],lims[4]), col="lightblue")
  plot.map('world2',center=ofs,fill=T, add=T, yaxt="n", xaxt="n")
  box(lwd=3)
  lines(c(-70, 190)+ofs, c(-60, -60), lwd=2, lty=1)
  lines(c(-60, 140)+ofs, c(-35, -35), lwd=2, lty=1)
  lines(c(140, 190)+ofs, c(-40, -40), lwd=2, lty=1)
  lines(c(153, 190)+ofs, c(-30, -30), lwd=2, lty=1)
  lines(c(-20, 14)+ofs, c(-20, -20), lwd=2, lty=1)
  lines(c(35, 44)+ofs, c(-20, -20), lwd=2, lty=1)
  lines(c(49, 120)+ofs, c(-20, -20), lwd=2, lty=1)
  lines(c(100, 130)+ofs, c(-10, -10), lwd=2, lty=1)
  lines(c(-70, -70)+ofs, c(-60, -55), lwd=2, lty=1)
  lines(c(-20, -20)+ofs, c(-60, -20), lwd=2, lty=1)
  lines(c(60, 60)+ofs, c(-60, -35), lwd=2, lty=1)
  lines(c(80, 80)+ofs, c(-35, -20), lwd=2, lty=1)
  lines(c(100, 100)+ofs, c(-20, -10), lwd=2, lty=1)
  lines(c(120, 120)+ofs, c(-60, -34), lwd=2, lty=1)
  lines(c(130, 130)+ofs, c(-12, -10), lwd=2, lty=1)
  lines(c(140, 140)+ofs, c(-40, -37), lwd=2, lty=1)
  lines(c(160, 160)+ofs, c(-60, -40), lwd=2, lty=1)
  lines(c(170, 170)+ofs, c(-40, -30), lwd=2, lty=1)
  lines(c(190, 190)+ofs, c(-60, -30), lwd=2, lty=1)
  axis(1, at=seq(lims[1],lims[2],by=10), labels=F)
  axis(2, at=seq(lims[3],lims[4],by=5), labels=F)
  latseq <- seq(lims[3]+10,lims[4]-10,by=10) ;latseq2 <- as.character(latseq)
  lonseq <- seq(lims[1]+20,lims[2]-20,by=20) ;lonseq2 <- as.character(lonseq-ofs)
  latseq2[latseq < 0] <- paste(abs(latseq[latseq < 0]),"S",sep="")
  latseq2[latseq > 0] <- paste(latseq[latseq > 0],"N",sep="")
  lonseq2[lonseq - ofs < 0] <- paste(abs(lonseq[lonseq - ofs < 0]-ofs),"W",sep="")
  lonseq2[lonseq - ofs > 0] <- paste(lonseq[lonseq - ofs > 0]-ofs,"E",sep="")
  lonseq2[lonseq - ofs > 180] <- paste(360 - lonseq[lonseq - ofs > 180]+ofs,"W",sep="")
  axis(2, at=latseq, labels=latseq2, cex.axis=0.75)
  axis(1, at=lonseq, labels=lonseq2, cex.axis=0.75)
  text(115+ofs,-15,"1",cex=1.7,font=2)
  text(100+ofs,-27,"2",cex=1.7,font=2)
  text(130+ofs,-33,"3",cex=1.7,font=2)
  text(155+ofs,-35,"4",cex=1.7,font=2)
  text(180+ofs,-35,"5",cex=1.7,font=2)
  text(175+ofs,-50,"6",cex=1.7,font=2)
  text(140+ofs,-47,"7",cex=1.7,font=2)
  text(90+ofs,-47,"8",cex=1.7,font=2)
  text(20+ofs,-47,"9",cex=1.7,font=2)
  text(-45+ofs,-47,"10",cex=1.7,font=2)
  text(-20+ofs,-7,"11",cex=1.7,font=2)
  text(180+ofs,-7,"12",cex=1.7,font=2)
  text(-110+ofs,-7,"12",cex=1.7,font=2)
  text(70+ofs, -7,"13",cex=1.7,font=2)
  text(51+ofs,-27,"14",cex=1.7,font=2)
  text(0+ofs,-27,"15",cex=1.7,font=2)
  mtext(side=3, line=0.5, plot_title)
}