How Do I Open an MD File?

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Naby
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How Do I Open an MD File?

Post by Naby »

I have some MD files I have downloaded locally but I can't figure out how to open them. I have created a local dataset in the ADDE Data Manager but I noticed that the MD format wasn't a selection in the Edit Local Dataset window. Which format should I select for this file type?

Thanks for the help.

Chris
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bobc
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Re: How Do I Open an MD File?

Post by bobc »

Hi Chris,

As of right now, local point servers do not exist in McIDAS-V, so there is no way to read in MD files. We have an inquiry open to add local point servers (Inquiry 2155), though I have no estimate on when this will be completed. If it's possible to get your data in another format of point data (e.g. point netCDF, csv, txt) then you would likely be able to load the data through the General>Files/Directories chooser. Please let me know if you can get your data in another format and if you have trouble getting it into McIDAS-V.

Thanks,
Bob Carp
McIDAS User Services
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Naby
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Re: How Do I Open an MD File?

Post by Naby »

Thank you Bob. I'm trying to view CIMSS AMV data. I think it is only available in image form and as MD files. One of the people I contacted for help on accessing the data mentioned using McIDAS to view it.

Regards,
Chris
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mug_admin
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Re: How Do I Open an MD File?

Post by mug_admin »

Hi Chris,

They were likely talking about McIDAS-X, which does have local point servers capable of working with MD files. There's a bit of documentation about this on the DSSERVE page of the McIDAS-X User's Guide. Please note that McIDAS-X does require a license and you must be in the McIDAS Users Group' to download the software.

Please let me know if you have any additional questions about this.

Thanks,
Bob
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Naby
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Re: How Do I Open an MD File?

Post by Naby »

Thank you Bob, I'll look into McIDAS-X. I appreciate all of the help.

Chris
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bobc
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Re: How Do I Open an MD File?

Post by bobc »

Hi Chris,

After looking at the Tropical Cyclones Archive page I saw that you can download the data in ASCII text format. This format can be loaded into McIDAS-V as a text data source and wind barbs can be plotted. For example, here is an image of GOES-16 AMVs from 12/02/2020:
amv_image.png
I'm not entirely sure what you are looking to plot, but below are some steps to reproduce this image after downloading a data file:
  1. Through the General>Files/Directories chooser of the Data Explorer, select "Text Point Data files" from the top Data Type dropdown menu. Navigate to the directory containing your data file, select the file, and click Add Source.
  2. At this point, a Point Data window will appear where you need to tell McIDAS-V what the different columns of data are. Follow the screenshot below for what can be entered. Note that after entering this once, you can click Preferences>Save Current, enter a name, and click OK. Next time you load a file like this, instead of manually entering everything, you can simply click Preferences>name and everything will fill in for you. After everything is entered, click OK.
    amv_PointDataWindow.png
    A couple additional comments here:
    - I am not sure what the units of SPEED are in this data. I looked around a bit and couldn't verify if the units are knots, m/s, or mph. Most of the time I've seen files like this they use m/s so that's what I'm using for this example, but this is worth investigating to make sure the correct speed is used.
    - I am not sure what "rff", "qi", and "int" are. If you know what they are, you can specify units for them.
  3. In the Field Selector tab of the Data Explorer, select "Point Data" from the Fields panel. In the Layout Model subset tab, choose Observations>Winds for the layout model and click Create Display.
Note that you can expand "Gridded Fields" in the Field Selector and choose one of the fields in the file to create a display of. This would make it possible to plot your barbs on top of a display of wind speed. I don't believe it's possible to create a derived display of a variable not included in the data, such as absolute vorticity. This is possible with true gridded data, but not point data files. McIDAS-V also doesn't have the ability at this time to plot streamlines from point data, only gridded data sources.

Are you a student at a university? If so, and you have a *.edu email address, you may be able to access Unidata McIDAS. This has much of the same functionality as our version of McIDAS-X. There's a contact link on that page if you are interested in pursuing this option.

Please let me know if you have any further questions about this.

Thanks,
Bob
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Naby
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Re: How Do I Open an MD File?

Post by Naby »

Bob,
Thank you for the lengthy reply. I am a student with a .edu address so I'm going to try McIDAS-X from Unidata. I'm working through the installation steps now.

I really appreciate the tutorial for how to load the ASCII files! The parameters I'm interested in are all derived from the wind vectors so I don't think the ASCII data will work. I think the "rff" and "qi" values have something to do with quality checking the data. I'm not sure what is in the MD files, I'm hoping some of the other CIMSS AMV products (vorticity, wind shear, etc.) are there or that the MD data is gridded now that it looks like McIDAS-X is going to work for me.

Thank you also for the explanation of what can and can't be done with gridded vs. point data, that is good to know.

Again, I appreciate all of the help!

Chris
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