scaling assessment part3, functions to combine yearly assessment used in stage 8

debugging overall 30 years combination of assessment for region 4, stage 8

running stage 7 mosaicing for region 4 on 1999 for poster NASA biodiversity conference

running overall assessment stage8 30 years summary for region 4, South America

testing code with new flag value and masking file

fixing problem with masking and no data values

more debugging of mask and testing of code

fixing mask used and no data values

adding compression and debugging for valid range and rescaling of mosaicing

valid value range with gdal calc in mosaic function