One would be wonder the day span of the data extracted by VGT Extract, oriented to SPOT_VEG NDVI(Tool downwebsite: http://www.geoland2.eu/portal/system/vgtextract.html),  let us see the example below.

[1]    Predefine the ROI in VGTExtract, see StudyArea.

[2]    Set the input and output locations, see the red lines.

[3]    Click Start, the result will be in the directory of Output.

[4]    Day span analysis.

Raw data name: SV05_VG2_S10___VI__20071031220350_20071110235404_CVB_000000_SE-Asia_V001.ZIP.

20071031220350 indicates the beginning, and 20071110235404 termination.

Extracted data name: NDV_20071101__Extract.tif.

Time term is 20071101 only. It illustrates the day span from 20071031 to 20071110.

Now, we can understand the naming regulation run by VGT Extract, e.g. 20071101 describes the days from 20071031 to 20071110.