McIDAS-V Support Forums

Hello,

I'm trying to view MODIS imagery using McIDAS-V 1.8 in Windows 10. I have downloaded 2 granules; MOD021KM.A2016143.1730.061.2017326031200.hdf and MOD021KM.A2016143.1735.061.2017326031219.hdf from https://ladsweb.modaps.eosdis.nasa.gov/ ... /2016/143/. I imported them Data Sources>Satellite>Hydra. In the field selector I selected Multispectral>Emissive Band, then Image Display, and Band 31. The images displayed are as the attachment below. Both 1730 and 1735 imagery has some spikes that goes out of the granules coverage. And when displayed together, the spikes from one granule will be on top of another granule.

Is this normal?

In replicating a publication, I downloaded MYD021KM.A2003284.0215.061.2018010015024.hdf from https://ladsweb.modaps.eosdis.nasa.gov/ ... /2003/284/. The image displayed is as attached. It's even more weird.

In relation to the post above. I tried comparing the between the image from McIDAS-V to a publication by Chenoli et. al. 2015. The result is as attached. Dr. Matthew Lazzara (University of Wisconsin-Madison) pointed out that this should not be the case, and I should be getting the same resolution as in the publication.

Hello-

I was testing with these granules obtained from the ladsweb website.

1. I could not replicate the spikes in your first post with the 2 granules from 2016. I was using the "South Pole" projection with some better success (from your display window choose Projections>Predefined>South Pole). I noticed your domain and projection is somewhat different. Did you define and create your own projection or using something else?

2. I could not replicate the messy display, and again, I'm wondering what projection you are using? Using the South Pole projection might help.

3. With the Hydra display chooser, it does sample the data during display, so I wasn't surprised to see the lower resolution display when I tested this. However, I did try our most recently nightly version which displayed at a higher resolution with updates we have. It is fairly stable at the moment and if you'd like to try it, you can download it from http://www.ssec.wisc.edu/mcidas/software/v/unstable/

When testing the granules from posts 1 & 2, I also noticed nicer display characteristics using the newer nightly version. So, if updating your McIDAS-V version is an option, I'd suggest that. We've typically had issues with displaying satellite images that straddle the dateline. There are some updates in this nightly version to help that. I will also reach out to other colleagues to see if there is any other information that would help your displays.

Thanks, Jay
McIDAS User Services

Hello Jay,

1 and 2. I'm using South Pole projection and a defined Viewpoint centered on Ross Sea. Even without using custom Viewpoint, and just South Pole Projection, it is still the same.

3. I would love to test it as well. However I could not download the nightly version. The link is telling me to sign in. Would you be able to help me in downloading the nightly version?

Yunus.

Edit: After going through Preferences, I change Formats & Data > Data > Sampling Mode from Weighted Average to Nearest Neighbor. There's no longer any spikes. I guess this is due to missing data, and the Weighted Average option doing something it's not supposed to do. However the resolution remains low and I'm unable to increase the resolution of the displayed image.

Hi Yunus-

I forgot to give the password for the nightly, my apologies. The username and password for the download are both: mcv

Thanks, Jay

Hello Jay,

I'm happy to inform you that using the beta version I am able to display MOD021KM at high resolution, which I assume is its native resolution. I have also attached a screenshot of it here. Please let me know, if there's anything more that needs attention.

As a side note, I don't see any spike reported in the first and second post in this v1.9beta1, even after switching to Weighted Average sampling method.