McIDAS-X Learning Guide
Version 2020

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Real-time Data Access - Satellite Imagery (Continued)

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, .SITE, and .USER. 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.

This exercise will cover the GEO command using a GEODATA.USER file that contains the free datasets being used in the Learning Guide. (If you have access to SSEC's polar orbiting data servers, or have your own data servers for polar orbiting data, you can try using LEO with similar examples.)

1. List and read through the GEO help.

   Type:    HELP GEO

2. Erase frames 1 through 4.

   Type:    ERASE F 1 4

3. Download a GEODATA.USER that will allow the GEO command to access free GOES geostationary datasets. The GEODATA.USER file should be placed in the <local-path>/mcidas/data directory.

   Download the file from ftp.ssec.wisc.edu.

   ftp ftp.ssec.wisc.edu
   login anonymous
   prompt
   binary
   cd pub/mug/Data/Satellite
   get GEODATA.USER

4. 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.USER 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.

5. Find and display a geostationary water vapor image centered over Vancouver, Canada using a filter. Display the image on frame 2.

   First, find the station ID for Vancouver, Canada.

   Type:    STNLIST CO=CA MATCH=VANCOUVER

   IDN ID Station Name Data Types ST CO LAT LON ELE ----- ----- -------------------- ----------------- -- -- ---------- ---------- ---- 71042 ---- VANCOUVER HILLCREST 36 BC CA 49:13:48 123:06:00 84 71201 CWHC Vancouver Automatic M 36 BC CA 49:18:00 123:07:00 2 71784 CWWA W Vancouver Automati M 36 BC CA 49:21:00 123:11:00 178 71892 CYVR Vancouver Intl Air-P M 36 T BC CA 49:11:00 123:10:00 3 --- WHC VANCOUVER (AUTOB V BC CA 49:17:00 123:07:00 2 --- WVR VANCOUVER V BC CA 49:11:00 123:11:00 0 --- WWA W VANCOUVER AUTO V BC CA 49:21:00 123:10:00 178 --- YVR VANCOUVER/B.C. V BC CA 49:01:00 123:09:00 2 Number of stations listed: 8 STNLIST: Done

   After locating the station ID, use the GEO command to display the image.

   Type:    SF 2;GEO CYVR WV ON=FILTER TIME=0

   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. TIME=0 is specified to select a desired time to display for the current day.

6. On frame 3, display the previous day's geostationary image centered over your home town from the current time.

   Type:    SF 3;GEO 'FORT ATKINSON[JEFFERSON],WI,US' DAY={enter previous day's date}

   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.

7. Display the 12 UTC geostationary infrared image centered over Tahiti on frame 4.

   Type:    SF 4;GEO 'TAHITI,,PF' IR TIME=12 RES=5

   This example displays the closest 12 UTC infrared image centered over Tahiti and displays it with a 5 km resolution. Note that two commas appear between the city (Tahiti) and country code (PF) because if only one comma is specified, it's assumed to be a state or province code.

8. Display the most recent shortwave infrared image over the United States with no command output, a enhanced stretch to the image, and a yellow map.

   Type:    GEO USA SW OFF=ECHO ON=FILTER MCOLOR=3

   This entry finds the satellites 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.

Manipulating Satellite Images

1. Display the GOES-West Full Disk IR image in its original resolution (2 km) on frame 1. Center the image on earth coordinates 0° and 137°, and show frame 1 once the image is loaded.

   Type:    ERASE F 1 4
   Type:    IMGDISP RTGOESS/FD 1 BAND=13 LAT=0 137 SF=YES;MAP X X LALO

2. Decrease (blow down) the image resolution of the GOES-West Full Disk image by a factor of 5 and display it on frame 3.

   Type:    IMGDISP RTGOESS/FD 3 BAND=13 LAT=0 137 SF=YES MAG=-5;MAP X X LALO

3. Magnify (blow up) the image resolution of the GOES-West Full Disk image by factor of 5 and display it on frame 2.

   Type:    IMGDISP RTGOESS/FD 2 BAND=13 LAT=0 137 SF=YES MAG=5;MAP X X LALO

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 GOES-West IR image to a mercator projection centered on the Seattle-Tacoma International Airport, and place it in the fourth position in the MYDATA/IMAGES dataset. Change the output resolution, but only create a 480x640 sized image. Note: the MYDATA/IMAGES dataset was initially setup in ADDE - Getting Started.

   Type:    DSSERVE ADD MYDATA/IMAGES 1 9999 "ALL AREA FILES
   Type:    IMGREMAP RTGOESS/FD MYDATA/IMAGES.4 STATION=KSEA PRO=MERC RES=5 SIZE=480 640 BAND=13

9. List out the directory information for these images.

   Type:    IMGLIST RTGOESS/FD FORM=BAND;IMGLIST MYDATA/IMAGES.4 FORM=BAND

   Image file directory listing for:RTGOESS/FD Pos Satellite/ Date Time Center Res (km) Image_Size sensor Lat Lon Lat Lon --- ------------- ------------ -------- ---- ---- ----- ----- ------------ 192 GOES-17 3 OCT 20277 00:40:31 0 137 Band: 1 0.47 um VIS aerosol-over-land 1.00 1.00 10848 x10848 Band: 2 0.64 um VIS clouds fog, insol, winds 0.50 0.50 21696 x21696 Band: 3 0.86 um Near IR veg/burn scar,aerosol, w 1.00 1.00 10848 x10848 Band: 4 1.37 um Near IR cirrus cloud 2.00 2.00 5424 x 5424 Band: 5 1.6 um Near IR cloud phase, snow 1.00 1.00 10848 x10848 Band: 6 2.2 um Near IR land/cloud, vege, snow 2.00 2.00 5424 x 5424 Band: 7 3.9 um IR Sfc, cloud, fog, fire, winds 2.00 2.00 5424 x 5424 Band: 8 6.2 um IR High-level WV, winds, rainfall 2.00 2.00 5424 x 5424 Band: 9 6.9 um IR Mid-level WV, winds, rainfall 2.00 2.00 5424 x 5424 Band: 10 7.3 um IR Lower-level WV, winds & SO2 2.00 2.00 5424 x 5424 Band: 11 8.4 um IR Total WV cloud phase, dust 2.00 2.00 5424 x 5424 Band: 12 9.6 um IR Total ozone,turbulence,wind 2.00 2.00 5424 x 5424 Band: 13 10.3 um IR Surface & cloud 2.00 2.00 5424 x 5424 Band: 14 11.2 um IR Imagery,SST,clouds,rainfall 2.00 2.00 5424 x 5424 Band: 15 12.3 um IR Total water, ash, and SST 2.00 2.00 5424 x 5424 Band: 16 13.3 um IR Air temp, cloud hgt and amt 2.00 2.00 5424 x 5424 Image file directory listing for:MYDATA/IMAGES Pos Satellite/ Date Time Center Res (km) Image_Size sensor Lat Lon Lat Lon --- ------------- ------------ -------- ---- ---- ----- ----- ------------ 4 GOES-17 3 OCT 20277 00:30:31 47 122 Band: 13 10.3 um IR Surface & cloud 3.38 3.38 480 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 United States map (the default).

    Type:    IMGDISP MYDATA/IMAGES.4 4 SF=YES;MAP FILE=OUTLUSAM

11. Loop all of the GOES-West 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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