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20010328: lesson aimed at retrieving historic Unidata-Wisconsin data



>From: Edward Hindman <address@hidden>
>Organization: CCNY
>Keywords: 200103162320.f2GNK2L07189 McIDAS-X ADDE

Ward,

>I am continuing to work with my students and McIDAS.  They have learned
>elementary manipulations of current satellite imagery; that is, data
>that are on our LDM (last 10 hours are saved).  Now, I need to teach
>them how to retrieve imagery from the SSEC that's older than 10 hours
>because they will be studying earth and atmospheric phenomena for a
>project, and they will need to get data from the "neartime" directory
>at SSEC.
>
>Consequently, below is the instructions I used last Spring, modified to
>the limits of my knowledge.  Would you please read the lecture and
>update the old commands with the new commands.

OK.

>I need to teach this
>material beginning at 2 pm EST tomorrow, 29 Mar.

Yikes!

>I apologize for the short-fused request.

I am glad I looked at the support email inbox when I did.  Just for
reference, I will be out of the office tomorrow, so any modifications that
need to be made to the exercise will have to be done today or tonight.


Revised Lecture Follows:

EAS 308 Lecture 16

Collection archived satellite data from UW/SSEC

    Motivation
    Steps

Motivation:

All of the meteorological data at CCNY Weather Station/Computer
Laboratory (WSCL) are received via the Internet Data Delivery (IDD)
system of the NSF-funded University Data Program, Boulder, CO and are
stored temporarily on halo.

The satellite images received through the IDD are only stored for 10
hours. The temporary storage is necessary because we have limited disc
space and no full-time systems operator to manage the incoming data.
But, the University of Wisconsin Space Science and Engineering Center
(UW/SSEC) in Madison, WI has the both the computer systems and the
operators to store the data for long periods, like years. We are
connected to this data source via Internet.

The purpose of today's study is to learn how to retrieve satellite data
for the past 30 days from the SSEC and analyze the data using our
McIDAS software.  Thus, you will be on your way for your projects; you
will be able to obtain the data you need.

Step 1: Connect to the SSEC

Connect to Cirrus, the machine running McIDAS, as follows:

    Click on  "Start", "Run", and type telnet cirrus.sci.ccny.cuny.edu
    Login: wxnut
    Pswd: 1wxnut

At the Cirrus prompt execute the following commands:
    %cd /home/wxnut/mcidas/data/ (this puts you into our familiar directory 
                                  where your data will reside)
    %ftp unidata.ssec.wisc.edu   (this calls the SSEC computer)
    Name: XXXXXX
    Password XXXXXX
    ftp> cd neartime             (past 30 days of data)
    ftp> cd yyyymmdd             (get into the directory for the day you desire)
    ftp> binary
    ftp> hash

List the data you are looking for, type 

    dir *.goes8ir   for east coast thermal infrared images
    dir *.goes8vis  for east coast visible images
    dir *.goes8wv   for east coast water vapor images
    dir *.goes10ir  for west coast thermal infrared images
    dir *.goes10vis for west coast visible images
    dir *.goes10wv  for west coast water vapor images

>Tom: I got this far OK.  But, when I looked ahead at the next steps and
>saw AREAxxxx and a whole bunch of old commands, I called you and you
>were out.  All the commands below were written for Halo upon which our
>McIDAS and LDM were running last Spring.  Currently, McIDAS is running
>on Cirrus and the LDM is on Halo.  So, I assume I ftp images from SSEC
>to somewhere in Cirrus and then retrieve them with the IMGPROBE
>command, etc.

Right.

>Please read on and you will get the gist of what I hope
>to teach tomorrow (29 March beginning at 2 pm EST).  I'd be grateful if
>you could update the commands.

Step 2: Get the file(s) you need  

To get an IR satellite image type 

    get 200103212315.goes8ir AREAxxxx

This gets east coast image for 2315GMT on 13 July 1996 and gives it a
filename AREAxxxx that must be specified. 

NOTE: Our incoming data from the IDD reserves AREA numbers 0060 to
1100, and storage of topography images reserves AREA numbers 9000 to
9999, so do not use these numbers as you could overwrite current data.
Prof. will assign AREAxxxx numbers.

The same statement, modified for the type of file, works for the
visible and water vapor images. Make sure you change your AREAxxxx name
to not overwrite your earlier retrieved files.

When you have received your data from the SSEC, type bye.

Step 3:  Activate McIDAS on a PC by double-clicking on the McIDAS-X icon 
(you may have to double-click again after Exceed loads)

Step 4: Display your image and cut down the image to store

First, make sure that your McIDAS session has a dataset named MYDATA/IMAGES
defined:

    DSSERVE LIST MYDATA

One of the lines from this listing should look like:

MYDATA/IMAGES            IMAGE AREA 1-9999           All images in AREA format

If your listing does not contain an entry for MYDATA/IMAGES, create this
set as follows:

    DSSERVE ADD MYDATA/IMAGES AREA 1 9999 "All images in AREA format

Assuming that you stored the image you FTPed in AREA2000, display it
image back in the McIDAS command mode as follows:

    SF 1
    IMGDISP MYDATA/IMAGES.2000 1 LATLON=35 70 EU=IMAGE.ET REFRESH='EG;MAP H'

You may be studying a feature that occupies a small portion of the
image.  The full-screen image occupies 480 lines along the y-axis and
640 lines along the x-axis. To save just what you need of the image
estimate the latitude and longitude of the center of the
region you wish to save (35N and 70W in this example). You can find the
latitude and longitude for any point using the Alt-E key command. Then,
type the following commands to "cut-down" your image:

    IMGCOPY MYDATA/IMAGES.2000 MYDATA/IMAGES.2010 LATLON=35 70 MAG=2 SIZE=300 
300
    IMGDISP MYDATA/IMAGES.2010 2 EU=IMAGE SF=YES REFRESH='EG;MAP H'

This will display from AREA2000 the 300 (y) by 300 (x) line region
centered at latitude 35N and longitude 70W in frame 2 with a
magnification of 2 and store the cut-down image in AREA2010. You will
have to experiment with the values of latitude, longitude and the size
of the region to display what you want. When you have a "cut-down"
image, erase the original file from Cirrus /home/wxnut/mcidas/data/ to
conserve memory.

You know how to determine IR temperatures using the IMGPROBE command
for a region. Also, you can obtain the temperature in one pixel by
holding the ALT key and hitting the D key.

Step 5: Print your "cut-down" image

You can print the image displayed in any frame (Frame 2 in this
example) using the following steps. In the McIDAS command line type,

    FRMSAVE 2 filename (use your initials for the filename with no extension)

This command saves Frame 2 in a file named filename.GIF in
/home/wxnut/mcidas/data/. Now, ftp the .GIF image to your diskette so
you can print it. Then, delete the .GIF image from Cirrus. Load
filename.GIF into "Micrografx" and follow the steps from Lect/Lab 15.

Class exercise:

Each student log onto SSEC and retrieve a file to be used in their
project, cut down the image and print it.

When you have completed the exercise, exit all windows and leave the
computer as you found it.


I hope that this was in time and helped...

Tom

>From address@hidden Wed Mar 28 19:06:45 2001

Tom:

Thanks a bunch!

Your ADDE revisions to my exercise all make sense and the exercise works;  
works almost as well as in the "good old days".

Sincerely,

Ward Hindman


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