function refresh (showStyle){
//get data from the HTML form
var myForm = document.ImageForm;
var index = myForm.Product.selectedIndex;
var typeid = myForm.Product[index].value;
var index = myForm.Year.selectedIndex;
var year = myForm.Year[index].value;
var index = myForm.Week.selectedIndex;
var week = myForm.Week[index].value;
//get the cuurent date from user computer
var now = new Date();
var cur_week = getCurrentWeek();
var cur_year = getCurrentYear();
//adjust year & week based on different HTML button
var isNeedResetYearWeek =0;
if(showStyle == "showNextWeek") {
week++; if(week > 52) { year++; week=1; }
isNeedResetYearWeek = 1;
}
if(showStyle == "showPrevWeek") {
week--; if(week <=0 ) { week=52; year--; }
isNeedResetYearWeek = 1;
}
if(showStyle == "showNextYear") {
year++;
isNeedResetYearWeek = 1;
}
if(showStyle == "showPrevYear") {
year--;
isNeedResetYearWeek = 1;
}
var yrwk = year *100 + Math.round(week);
var curYrwk = cur_year *100.0 + cur_week;
if( yrwk < 198135 || yrwk > curYrwk ) {
alert("Data requested is not available, please check: year=" +year+" week="+week);
return ;
}
if(typeid == 0) { alert(" Please select a data type"); return; };
if(year == 0) { alert(" Please select a year"); return; };
if(week == 0) { alert(" Please select a week"); return; };
var bNodata=0;
if(imagetype == "DIFF_VTI_YEARLY" && (yrwk < 198235) ) bNodata =1;
if(imagetype == "DIFF_VTI_WEEKLY"&& (yrwk <= 198135) ) bNodata =1;
if(imagetype == "DVT" && (yrwk <= 198139) ) bNodata =1;
if( bNodata == 1){
alert("data requested is not available for this week: year=" +year+" week="+week);
return ;
}
if( isNeedResetYearWeek == 1) {
//alert("reset "+year+" "+ week);
for(i=0; i< myForm.Week.length; i++){
if(myForm.Week[i].value == week) {
myForm.Week[i].selected = true;
break;
}
}
for(i=0; i<= myForm.Year.length; i++){
if(myForm.Year[i].value == year) {
myForm.Year[i].selected = true;
break;
}
}
}
baseurl = getVHrootURL();
//image
var imagetypes =["SMN","SMT","VCI","TCI","VHI","FireRisk","VHchangeWeekly","VHchangeYearly"];
var imagetype = imagetypes[typeid-1];
var picturepath = baseurl + "/"+ year +"/";
var Img_ext=".png"
var yearweek = year + "" + week;
if (week <= 9) { yearweek = year + '0' +week;}
var imgName = imagetype +"_" + yearweek + Img_ext;
img_url= picturepath +imgName;
var colorbar= getColorBarURL(imagetype );
if( bNodata == 1){
parent.MainImageFrame.document.writeln(""
+ "Sorry, the requested image is not available online.
"
+"");
parent.MainImageFrame.document.close();
return;
}
switch (imagetype) {
case imagetype='SMT': prodTitle = "Smoothed Brightness Temperature"; break;
case imagetype='SMN': prodTitle = "Smoothed NDVI"; break;
case imagetype='VCI': prodTitle = "Vegetation Condition Index"; break;
case imagetype='TCI': prodTitle = "Temperature Condition Index"; break;
case imagetype='VHI': prodTitle = "Vegetation Health Index"; break;
case imagetype='FireRisk': prodTitle = "Fire Risk"; break;
case imagetype='VHchangeWeekly': prodTitle = "Weekly Vegetation Health Change"; break;
case imagetype='VHchangeYearly': prodTitle = "One-Year Vegetation Health Change"; break;
}
if (imagetype.indexOf("VHchange") == -1) {
periodText = "Week " + week + ", " + year;
}else if ((imagetype.indexOf("Weekly") != -1) && (week >= 2)) {
periodText = year + ", Week " + week + " minus Week "+ (week-1);
}else if ((imagetype.indexOf("Weekly") != -1) && (week = 1)) {
periodText = "( Week " + week+","+year + ") minus (Week 52,"+ (year-1)+")";
}else if (imagetype.indexOf("Yearly") != -1) {
periodText = "(Week " + week + ", " + year + ") minus (Week "+ week +", " + (year-1) +")";
}
// 2004 2006 2011
var day1_ofyear=[-2, 3 ,2,1,0,-2,-3, 3,2, 0,-1,-2]; //start from 2004
var day= (week-1) * 7 +1; //day1_ofyear[year-2004] ;
var Jyear=year;
if (day < 1) {
var NdaysInyear = ((Jyear % 4) == 0)? 366: 365;
day += NdaysInyear ;
Jyear--;
}
if(day <100 && day >= 10) day ='0' + day;
if(day < 10) day ='00' + day;
var image_filename = imagetype +"-Weekly-" +Jyear+ "-" +day+".png";
GLOBAL_img_url= baseurl +"/Visual_Lab/" +imagetype + "/" + image_filename ;
// GLOBAL_img_url= "http://www.orbit.nesdis.noaa.gov/smcd/emb/vci/VHimages/Visual_Lab/SMN/SMN-Weekly-2009-040.png";
GVI_backgroundmap= parent.GmapImageFrame.GVI_backgroundmap;
parent.GmapImageFrame.map.removeOverlay(GVI_backgroundmap);
var boundaries = new GLatLngBounds(new GLatLng(-55.125,-180.), new GLatLng(75.024,179.9));
GVI_backgroundmap = new GGroundOverlay(GLOBAL_img_url, boundaries);
parent.GmapImageFrame.map.addOverlay(GVI_backgroundmap);
parent.GmapFootFrame.document.writeln(""+
GLOBAL_img_url +"
" +prodTitle +", "+periodText +"
"+
"![color bar, file=" + colorbar +"]("+colorbar +")
" +
"");
parent.GmapFootFrame.document.close();
}