I'm glad you are able to replicate your Python display in McIDAS-V now. I looked through some older (May 2015) cloud mask EDRs I have and they seem to have the same issue as your data. Looking at some documentation from NOAA/NESDIS STAR on this data (see link here
), there are a variety of tests done to determine if each data point is snow/ice. It seems like they've improved how well the snow/ice mask works over time. I ordered some data from yesterday and it looks to be more realistic than my older data. One issue that looks to remain in the data is that some pixels are classified as snow/ice when they are also classified as being "Confidently Cloudy" from the "QF1_Cloud_Detection_and_Confidence_Pixel" variable. You can use a formula in McIDAS-V to mask these pixels out from the display. Here are some steps:
- Load your data into the Field Selector.
- From the Field Selector, choose "Formulas" from the left panel.
- Select the "Imagery > Mask Value" formula and the "Imagery > Image Display" display type.
- Click Create Display.
- In the Select Input window, enter the values in this image and click OK:
Here, we're defining to only display values less than 3. 3 is the value from the "QF1_Cloud_Detection_and_Confidence_Pixel" for "Confidently Cloudy". This will plot snow/ice pixels only where the cloud detection field is "Confidently Clear" or "Probably Clear".
- From the Field Selector, in the left panel (inputFieldForMask), choose the "QF1_Cloud_Detection_and_Confidence_Pixel". This is the field we are passing through the mask to only include pixels with values less than 3. In the right panel (displayFieldToBeMasked), choose the QF1_SnowIce_Surface_Pixel field. This is the field that will be displayed where the "QF1_Cloud_Detection_and_Confidence_Pixel" value is less than 3.
- Click OK.
Now, you should only see the snow/ice pixels where the the pixels aren't considered to be "Confidently Cloudy". There is an overall quality flag variable in the file. You can select the "QF1_Cloud_Mask_Quality_Pixel" field from the Field Selector and click Create Display (after any subsetting in the Region tab). Probing the display by holding down the middle mouse button will print out text output at each pixel location. For example, the pixels could say "High", "Medium", or "Low". From what I've seen, there doesn't appear to be a quality flag field specifically for snow/ice.
McIDAS Help Desk