McIDAS Learning Guide
Version 2015

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Real-time Data Access - Satellite Imagery (Continued)

In the next part of this exercise, you will be introduced to two new commands, which find and display geostationary and polar orbiting satellite images over a geographical area. You will also use IMGREMAP to manipulate real-time satellite images.

Displaying Satellite Images Using GEO and LEO

GEO and LEO are "macro-like" commands which build and run multiple McIDAS commands to access satellite data.

GEO finds and displays GEOstationary satellite images over a specified point or region, while LEO finds and displays polar orbiting (or Low Earth Orbit) satellite images. GEO uses the GEO.*, MAP.*, and GEODATA.* context files, where .* refers to .CORE, .USER, and .SITE. Default parameter and keyword values are found in the GEO.* context files, regional map definitions are found in the MAP.* context files, and satellite coverage, instrument channels, resolution information, and boarding image datasets are defined in GEODATA.* context files. LEO uses the same context files, except for a change in name to LEO.* and LEODATA.*.

If you do not access your real-time data at SSEC, GEO and LEO may not work without changing the dataset names in the GEODATA.* and LEODATA.* files.

GEO and LEO have been designed so that the user does not need to know which satellite covers which earth location. The only thing the user needs to input is the geographical location that they are interested in. The commands find the applicable dataset(s) and display the images automatically.

  1. List and read through the GEO help.
    Type:  HELP GEO
  2. Erase frames 1 through 4.
    Type:  ERASE F 1 4
  3. Find and display a geostationary visible image centered over Torrance, California (KTOA) on frame 1.
    Type:  SF 1;GEO KTOA VIS
    First, the command searches for the latitude and longitude of the location defined in the first positional parameter. Then, it uses GEODATA.CORE to find the closest geostationary satellite to use. Next, if the user has not specified which channel to use, GEO will determine the channel, either visible or infrared, depending on the time of the day. Also, if the center point is at the edge of the satellite coverage, GEO will take the adjoining satellite and merge enough data to cover the rest of the image to create the composite. Finally, GEO will display the image with a map on the current frame.

  4. Find and display a geostationary water vapor image centered over Paris, France using a filter. Display the image on frame 2.

    First, find the station ID for Paris/Le Bourget, France.
     IDN   ID     Station Name         Data Types        ST CO LAT        LON         ELE
     ----- -----  -------------------- ----------------- -- -- ---------- ----------  ---- 
     07156  ----  Paris-Montsouris                          FR   48:49:00   -2:20:00    75
     07150 LFPB   Paris / Le Bourget   M    T               FR   48:58:00   -2:27:00    66
     07157 LFPG   Paris-Aeroport Charl M    T               FR   49:01:00   -2:32:00   118
     07149 LFPO   Paris-Orly           M 36 T               FR   48:44:00   -2:24:00    89
      ---  LFPW   Paris Met Center     M                    FR   48:50:00   -2:20:00    75
     Number of stations listed: 5
     STNLIST: Done
    After locating the station ID, use the GEO command to display the image.
    Use the ON= keyword to set any of the four GEO options, such as FILTER, to on or off. The parameter WV indicates to display a water vapor image.

  5. On frame 3, display the previous day's geostationary image centered over your home town from the current time.
    In the example above, the brackets [ ] indicate the county location. The DAY= keyword allows you to specify a day other than the current one. Valid entries for this keyword will depend on how many days of data are kept online in your servers.

  6. Display the 12 UTC geostationary infrared image centered over Bruxelles, Belgium on frame 4.
    Type:  SF 4;GEO 'BRUXELLES,,BE' IR TIME=12 RES=3
    This example displays the closest 12 UTC infrared image centered over Bruxelles and displays it with a 3 km resolution. Note that two commas appear between the city (Bruxelles) and country code (BE) because if only one comma is specified, it's assumed to be a state or province code.

  7. List and read through the LEO help.
    Type:  HELP LEO
  8. Display the most recent polar orbiting land vegetation image over the United States.
    Type:  LEO USA VEG
    This entry finds the polar oribiting satellite whose coverage includes the region defined by the map named USA in the MAP.USER /.SITE /.CORE file. It then displays the satellite's most recent image at the resolution needed to cover the region. For most users, the region will be the country of the United States because that's how USA is defined in the MAP.CORE file.

  9. Display the polar orbiting image over Japan with no map and no command output in the text frame.
    Type:  LEO 33 -130 OFF=ECHOS MAPS
  10. Display a polar orbiting image over Stoughton, Wisconsin in Dane County with the state boundary in green, and the county boundaries in orchid.

Manipulating Satellite Images

A major strength of McIDAS as a meteorological data analysis/display package is its ability to display and manipulate satellite images, even if the data is located on a remote server. With the IMGDISP command, you can change the image resolution displayed with the MAG= keyword. The IMGREMAP command allows you to remap images into new projections and create new image products.
  1. Display the Meteosat Full Disk IR image in its original resolution (3 km) on frame 1. Center the image on earth coordinates 0° and 0°, and show frame 1 once the image is loaded.
    Type:  ERASE F 1 4
    Remember, if you receive a partially black image, the image is probably in the process of being ingested. Try the command again in a few minutes. If you're still having problems, contact the server administrator.

  2. Decrease (blow down) the image resolution of the Meteosat Full Disk image by a factor of 5 and display it on frame 3.
  3. Magnify (blow up) the image resolution of the Meteosat Full Disk image by factor of 5 and display it on frame 2.
  4. Change the loop sequence to view the images in the order of increasing resolution.
    Type:  LS 3 1 2
  5. Loop the frames.
    Press:  Alt L
  6. When finished viewing the loop, turn the looping off.
    Press:  Alt L
  7. Change the loop sequence back to loop through the first four frames.
    Type:  LB 1 4
  8. Remap the latest Meteosat IR image to a mercator projection centered on London's Heathrow Airport, and place it in the fourth position in the MYDATA/IMAGES dataset. Change the output resolution, but only create a 480x640 sized image.
  9. List out the directory information for these images.
    Image file directory listing for:MSG/FD
     Pos Satellite/         Date       Time      Center      Res (km)   Image_Size
         sensor                                 Lat  Lon    Lat   Lon
     --- -------------  ------------  --------  ---- ----  ----- ----- ------------
     290  METEOSAT10    23 MAY 15143  02:45:00     0    0
       Band: 1    0.6 um VIS Cloud and Surface Features     3.02  3.00  3712 x 3712
       Band: 2    0.8 um VIS Aerosols over Water, Veg       3.02  3.00  3712 x 3712
       Band: 3    1.6 um Near IR - Surface, cloud phase     3.02  3.00  3712 x 3712
       Band: 4    3.9 um IR Low Cloud/Fog,Fire Detection    3.02  3.00  3712 x 3712
       Band: 5    6.2 um IR Upper-level Water Vapor         3.02  3.00  3712 x 3712
       Band: 6    7.3 um IR Mid-level Water Vapor           3.02  3.00  3712 x 3712
       Band: 7    8.7 um IR Total Water,Cloud Phase,Dust    3.02  3.00  3712 x 3712
       Band: 8    9.7 um Ozone                              3.02  3.00  3712 x 3712
       Band: 9    10.8 um IR Surface/Cloud-top Temp         3.02  3.00  3712 x 3712
       Band: 10   12.0 um IR SFC/Cloud Temp, Low-level WV   3.02  3.00  3712 x 3712
       Band: 11   13.4 um IR CO2, Cloud Heights             3.02  3.00  3712 x 3712     
    Image file directory listing for:MYDATA/IMAGES
     Pos Satellite/         Date       Time      Center      Res (km)   Image_Size
         sensor                                 Lat  Lon    Lat   Lon
     --- -------------  ------------  --------  ---- ----  ----- ----- ------------
       4  METEOSAT10    23 MAY 15143  02:45:00    51    0
       Band: 9    10.8 um IR Surface/Cloud-top Temp         3.11  3.11   480 x  640

    Notice that the second image now has a different center lat/lon and is a different size than the original image.

  10. Display the new image in frame 4 and draw a high-resolution European map.
  11. Loop all of the Meteosat images.
    Press:  Alt L
    By looking at these four images, you should be able to see how simple it is to create different products from the same source image (frame 1) without ever moving the source image from the remote server.

  12. When finished viewing the loop, turn the looping off.
    Press:  Alt L

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