McIDAS Learning Guide
Version 2006

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Grids and Grid Files - Listing Grids and Grid Files

1. Start a McIDAS session.

   At the Unix prompt:

   Type:  mcidas

   Your session should still be set for six frames from the last time you changed the Configuration GUI. If not, set it for six frames, as described in Getting Started.

2. Log on and initialize the workstation.

   Type:  LOGON initials project

3. List the grid files in the BLIZZARD dataset.

   Type:  DSINFO GRID BLIZZARD

4. List the grid file directory for these grid files.

   Type:  GRDLIST BLIZZARD/GRIDS.ALL FORM=FILE

   Each grid file has a dataset position, date the grid file was created, maximum number of grids the grid file can store, and a file description, as shown below.

   DATASET NAME: BLIZZARD/GRIDS Dataset Position Creation Date Max Grids Directory Title ---------------- ------------- --------- ------------------------------- 1 1993070 159 12Z 93070 NMC NGM TRAINING GRID 2 1993071 159 00Z 93071 NMC NGM TRAINING GRID 3 1993071 159 12Z 93071 NMC NGM TRAINING GRID 4 1993072 159 00Z 93072 NMC NGM TRAINING GRID 5 1993072 159 12Z 93072 NMC NGM TRAINING GRID

5. List the first ten grids in the first grid file in the dataset.

   Type:  GRDLIST BLIZZARD/GRIDS.1 GRID=1 10

   The first ten grids are listed in the Text and Command Window, which shows the dataset position, grid file description, parameter type, level, Julian date of the data, time of the data, source type, forecast hour, valid day/time, grid number, and projection.

   Dataset position 1 Directory Title= 12Z 93070 NMC NGM TRAINING GRID PARAM LEVEL DAY TIME SRC FHOUR FDAY FTIME GRID PRO ----- ------- ------------ -------- ---- ----- ------------ -------- ------ ---- Z 1000 MB 11 MAR 93070 12:00:00 ROI 0 11 MAR 93070 12:00:00 1 MERC T 1000 MB 11 MAR 93070 12:00:00 NGM 0 11 MAR 93070 12:00:00 2 MERC U 1000 MB 11 MAR 93070 12:00:00 ROI 0 11 MAR 93070 12:00:00 3 MERC V 1000 MB 11 MAR 93070 12:00:00 ROI 0 11 MAR 93070 12:00:00 4 MERC Z 850 MB 11 MAR 93070 12:00:00 ROI 0 11 MAR 93070 12:00:00 5 MERC T 850 MB 11 MAR 93070 12:00:00 ROI 0 11 MAR 93070 12:00:00 6 MERC U 850 MB 11 MAR 93070 12:00:00 ROI 0 11 MAR 93070 12:00:00 7 MERC V 850 MB 11 MAR 93070 12:00:00 ROI 0 11 MAR 93070 12:00:00 8 MERC Z 700 MB 11 MAR 93070 12:00:00 ROI 0 11 MAR 93070 12:00:00 9 MERC T 700 MB 11 MAR 93070 12:00:00 ROI 0 11 MAR 93070 12:00:00 10 MERC Number of grids listed = 10

6. Get the expanded listing of the first grid in this dataset.

   Type:  GRDLIST BLIZZARD/GRIDS.1 FORM=ALL

   The expanded listing includes information about the total points, the number or rows and columns, the time the grid was received, units of the parameter, scaling factor, lat/lon extents and increments.

   Dataset position 1 Directory Title= 12Z 93070 NMC NGM TRAINING GRID PARAM LEVEL DAY TIME SRC FHOUR FDAY FTIME GRID PRO ----- ------- ------------ -------- ---- ----- ------------ -------- ------ ---- Z 1000 MB 11 MAR 93070 12:00:00 ROI 0 11 MAR 93070 12:00:00 1 MERC Total pts= 1188 Num rows= 33 Num columns= 36 received: 0 000000Z No GRIB number information Units of gridded variable are GPM Scale of variable is: 2 Mercator Projection Min Lat= 20.00 Max Lat= 60.00 Min Lon= 52.50 Max Lon= 140.00 Latitude Increment= 1.2500 Longitude Increment= 2.5000 Number of grids listed = 1

7. List all the 500 mb height (Z) grids in the grid file in dataset position 5.

   Type:  GRDLIST BLIZZARD/GRIDS.5 LEVEL=500 PARAM=Z NUM=ALL

   The 0, 12, 24, 36, and 48 hour forecast grids for this level and parameter are listed.


8. List the statistical information for the 12 hour 500 mb height grid in this dataset.

   Type:  GRDINFO BLIZZARD/GRIDS.5 STAT LEVEL=500 PARAM=Z FHOUR=12

   Information about the maximum and minimum values, the mean and standard deviation of the values in the grid are listed.


9. List a histogram of the values for this same grid. Bin the values in 120 m segments and format the values as integers.

   Type:  GRDINFO BLIZZARD/GRIDS.5 HIST LEVEL=500 PARAM=Z FHOUR=12 BINSIZE=120 FORMAT=I5

10. List the 24 hour Relative Humidity grid point values between 35° and 40° N and 80° and 85° W from this dataset. Format the data as a real value with one decimal place.

    Type:  GRDINFO BLIZZARD/GRIDS.5 LIST PARAM=RH FHOUR=24 LAT=35 40 LON=80 85 FORMAT=F4.1

    Row, column, latitude, longitude, and values are listed for each grid point falling in this geographical region:

    Listing data from 24-hour forecast RH Grid at 850 MB from NGM Grid is at 120000 UTC on 1993072 from dataset: BLIZZARD/GRIDS Row Col Latitude Longitude Value Units Level Param 17 23 40.000 85.000 90.2 850 MB RH 18 23 38.750 85.000 86.2 850 MB RH 19 23 37.500 85.000 77.2 850 MB RH 20 23 36.250 85.000 74.7 850 MB RH 21 23 35.000 85.000 80.7 850 MB RH 17 24 40.000 82.500 96.7 850 MB RH 18 24 38.750 82.500 98.7 850 MB RH 19 24 37.500 82.500 98.7 850 MB RH 20 24 36.250 82.500 98.2 850 MB RH 21 24 35.000 82.500 97.2 850 MB RH 17 25 40.000 80.000 99.7 850 MB RH 18 25 38.750 80.000 99.7 850 MB RH 19 25 37.500 80.000 98.7 850 MB RH 20 25 36.250 80.000 97.7 850 MB RH 21 25 35.000 80.000 98.7 850 MB RH GRDINFO Done, Number of grids listed=1

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