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>From: "Mekonnen Gebremichael" <address@hidden> >Organization: Pratt School of Engineering, Duke University >Keywords: 200504201601.j3KG1gv2005753 McIDAS access Hi Mekonnen, >After a long hassle, mcidas is now up and running. It is my first time ever >to use mcidas. So I downloaded the user's guide, and skimmed through it. But >I still have difficulty performing the basic operations, like opening files, >viewing data, etc. So I am turning to you for help. The one big concept in McIDAS that users have to get used to is the "indirect" access to data through the ADDE. In McIDAS, data requests are sent to server processes that handle the file access for you. Those server processes can be run out of: - your own McIDAS session if the datasets are local to your account - from a remote server running on the same machine if the datasets are accessed by a different user - on a remote machine accessible through TCP/IP Ethernet Because of this design, the end user (you) have to stop thinking in terms of "I want to open and read that file" and start thinking in terms of "I want to access that member of a dataset". The thing that is not intuitive is the step where someone (you, your McIDAS administrator, or a McIDAS administrator for a different machine) configures a dataset. The configuration step is one of "teaching" McIDAS which files reside in what dataset. This is done through the use of a McIDAS command known as DSSERVE. To get a quick start, run the following from your McIDAS session: HELP DSSERVE The access to data through servers is known as the Abstract Data Distribution Environment (ADDE). Datasets in ADDE are just what you would think: sets of data. Those sets can be composed of like data (e.g., GOES imagery, model output grids, NEXRAD radar image products, point source data, etc.) or disparate data. ADDE datasets are organized by 'group's. A group is further organized by 'descriptor's. An ADDE 'group' can have a variety of types of data (like for a case study). A 'group+descriptor', however, can only have one type of data. The major types of data are IMAGE, GRID, TEXT, or POINT. The naming of an ADDE dataset is 'group/descriptor'. There are rules for what characters are allowed in both the 'group' and 'descriptor' names; see the online help for DSSERVE (HELP DSSERVE) for details. A McIDAS command requests an element of a set from an ADDE dataset group/descriptor. On top of that, a setting in the user's McIDAS session tells the command where the dataset 'group' lives (i.e., on which machine). >The file that I am interested in is "globir.02182.0015", it is a GOES-IR >image. I have attached the readme file associated with this data. My >question to you is: could you tell me, step-by-step, on how to view the >image and the data? OK. Assuming that your file is in the McIDAS AREA format, you would setup access to it by defining an ADDE dataset in which it exists. As an example, let's call your ADDE dataset group 'TEST'. Let's further create a subset of the group 'TEST' and name it 'IMAGES'. Here is a simple example of the creation of a dataset TEST/IMAGES in which your image can be found: - assume that your file is located in the directory /data/images; you have already said that it is named globir.02182.0015 <from your McIDAS-X session> DSSERVE ADD TEST/IMAGES AREA DIRFILE=/data/images/goesir.* "Test GOES IR image Assuming that the image _is_ in McIDAS AREA format, and assuming that it _is_ readable by you, you should now be able to list out information about it: IMGLIST TEST/IMAGES IMGLIST TEST/IMAGES FORM=ALL The listing(s) will tell you if you are able to read the file and if it is indeed in McIDAS AREA format. If the image is multibanded (more than one wavelength channel in it), you will need to specify the BAND= keyword in order to display what you want. here is an example that assumes that the image really is a GOES IR thermal (band 4) image: IMGDISP TEST/IMAGES.1 BAND=4 Next blow it down: IMGDISP TEST/IMAGES.1 BAND=4 MAG=-3 Please consult the online help for the meaning of the BAND= and MAG= keywords for IMGDISP. Also, it would be most useful if you would work through the McIDAS-X Learning Guide as this has everything noted above and lots more on how to use McIDAS. >Thanks much for your help, No worries. >p.s. please omit this email from appearing in the official Q&A site of your >page. I will do as you request, but am curious as to why you want the transaction omitted from our online tracking? Our idea is that new users should be able to benefit from transactions of past users and, thereby, bypass the need to contact support directly. When users choose to not have their inquiries listed in the online system, it prevents others from learning from their questions, so it makes our support job less likely to reach a wide audience. Cheers, Tom -- **************************************************************************** < Unidata User Support UCAR Unidata Program < (303)497-8643 P.O. Box 3000 < address@hidden Boulder, CO 80307 < ---------------------------------------------------------------------------- < Unidata WWW Service http://my.unidata.ucar.edu/content/support < ---------------------------------------------------------------------------- < NOTE: All email exchanges with Unidata User Support are recorded in the Unidata inquiry tracking system and then made publicly available through the web. If you do not want to have your interactions made available in this way, you must let us know in each email you send to us.