McIDAS User's Guide
Version 2019.1
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Displays image data.
IMGDISP dataset frame [keywords]
IMGDISP predprod [keywords]
dataset |
ADDE dataset name and position; specify one of the following formats: |
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group/descriptor.position alias.position |
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a position greater than zero represents an absolute position in the dataset; a position less than or equal to zero represents a relative position in the dataset based on image time, for example, 0 is the most recent and -1 is the next most recent; to use the default position, do not specify .position (no default for group/descriptor or alias; default=0 for position) |
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frame |
frame number to display the image; specify OPP to display the image on the frame opposite the current frame; see the CYCLE and SEQ keywords to maintain an image loop on a range of frames (default=current) |
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predprod |
predefined product in the IMGDISP.CORE, IMGDISP.SITE or IMGDISP.USER file; see the Remarks |
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LATlon= |
lat lon |
latitude and longitude of the image to place at the location specified in the PLACE keyword |
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LINele= |
line ele sys |
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line |
line number of the image to place at the location specified in the PLACE keyword (default=0) |
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ele |
element number of the image to place at the location specified in the PLACE keyword (default=line) |
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sys |
coordinate system of the line and ele values; specify either F for file (area) coordinates or I for image coordinates (default=F) |
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PLAce= |
location on the frame to place the point specified in the LATLON, STATION or LINELE keywords; use one of the following: |
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ULEFT |
upper-left corner of the frame (default when the LINELE keyword is used) |
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CENTER |
center of the frame (default when the LATLON or STATION keyword is used) |
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STAtion= |
station ID to place at the location specified in the PLACE keyword; specify as the ID, e.g., KMSN or YSSY, optionally followed by the station type in brackets, e.g., ARX[N] or ARX[V]; see the TYPE keyword in the STNLIST command for valid station types |
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DAY= |
selects from dataset images with the specified day |
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ID= |
selects from dataset images with the specified NEXRAD station ID, e.g., MKX |
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RTIme= |
bmin emin |
selects from dataset images within the specified range of minutes in the current hour; overrides the TIME keyword |
TIMe= |
btime etime |
selects from dataset images within the specified time range |
BANd= |
image band number to display (default=existing band for single-band images; no default for multiband images) |
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EU= |
name of the enhancement table to apply to the image |
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GEOres= |
YES |
displays the geographic resolution at the center of the source image for the resolution value in the annotation text at the bottom of of the frame |
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NO |
displays the image resolution factor (where "1" equals the base resolution of the instrument) for the resolution value in the annotation text at the bottom of the frame (default); if a positive MAG= is also specified then the displayed value is the image resolution factor divided by the MAG= value; if a negative MAG= is specified then the displayed value is the image resolution factor multiplied by the absolute value of MAG= |
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GRAy= |
NO |
does not display a grayscale bar (default) |
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YES |
adds a continuous grayscale bar to the bottom of the image |
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repeat inc start line adds a custom grayscale bar to the image |
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repeat |
brightness repeat factor (default=5) |
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inc |
brightness level increment; if greater than 0, the bar is incremented from 0 to 255; if less than 0, the bar is incremented from 255 to 0 (default=2) |
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start |
starting brightness level (default=0) |
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line |
starting TV line; must be greater than zero (default=number of lines in the frame minus 23) |
MAG= |
lmag emag |
line and element magnification of the data; use a positive integer to blow up and a negative integer to blow down (default=1 lmag) |
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NAVtype= |
LALO linc einc |
use lat/lon navigation instead of the regular (native) navigation; this keyword is valid only if the source image is area or AVHRR Level 1b format; linc and einc specify the image line and element increments, e.g., NAVTYPE=LALO 4 3 requests lat/lon nav using the data from every fourth line and every third element (default=use native nav; if you specify LALO, lat/lon nav is used and the linc and einc defaults are the computed values that result in using the largest number of data points allowable without exceeding the max size of the AUX block) |
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RECT |
remaps MODIS imagery into a rectilinear projection and applies a bowtie correction using MRTSwath (MODIS Reprojection Tool - Swath, package courtesy of the U.S. Geological Survey); use this keyword only when the source image is MODIS Level 1B or Level 2 data on a remote server with the MRTSwath package installed; this keyword is ignored if used with any other type of data |
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REFresh= |
'commands' gframe runs the specified McIDAS-X commands after IMGDISP displays the image; use gframe to specify the beginning frame to display graphics created with the commands; see the Remarks (no default for commands; gframe default=bfra when using the SEQ, CYCLE, or ALL keyword, otherwise default=frame) |
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SIZe= |
line ele |
number of lines and elements of the image to display; do not exceed the frame size (default=frame size); note that if you specify PLACE=CENTER with SIZE=line ele, the location specified in LATLON=, LINELE= or STATION= is displayed at the TV coordinates equal to the line and ele values divided by 2 |
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SU= |
name of the stretch table to apply to the image |
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TEXt= |
'text' fgd bgd the annotation line's text and foreground and background brightness levels; the beginning and ending single quotes are mandatory for specifying text other than the default image annotation (default=X 232 32) |
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TRACKing= |
YES |
tracks image if allowed by the server; tracking allows commands to receive data as it's being ingested by the server; commands complete when their data request has been fulfilled; tracking is only supported on some servers (e.g., Area, GVAR and MTSAT) and it can be disabled by the server administrator |
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NO |
does not track image so server only sends data that is currently available (default=value of MCTRACK environment variable; if MCTRACK is not set, default=value set by server or server administrator) |
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WL= |
displays band with image wavelength closest to the specified value; valid only with high spectral resolution data, e.g., Aqua AIRS |
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WN= |
displays band with image wave number closest to the specified value; valid only with high spectral resolution data, e.g., Aqua AIRS |
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ALL= |
bfra efra |
displays multiple images; if the number of frames in the range bfra-efra is greater than or equal to the number of images, all images are displayed in time order with the oldest image in bfra; if the number of frames is less than the number of images, images are displayed in all frames with the most recent image in efra, the second most recent image in the previous frame, etc.; do not use this keyword if a position other than the default value of 0 is specified in dataset |
REPeat= |
num pinc finc |
displays num number of images in the dataset; the image specified in dataset is displayed in the frame specified in frame; pinc and finc determine the position and frame increments for subsequent image loads; this keyword is valid only if the dataset position number, num, pinc and finc are positive integers (default=1 1 1) |
CYCle= |
inc bfra efra tol updates the range of frames bfra-efra by displaying the image specified in dataset on the frame determined by the following formula: frame=modulus((time-tol)/inc,numfra)+bfra see the Remarks (inc default=1:00, meaning a 1-hour increment; tol default=0, meaning no time tolerance; no default for bfra and efra) |
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SEQ= |
bfra efra |
updates the range of frames bfra-efra by displaying the image specified in dataset in the frame following the frame with the most recent image; the selected frame overrides the frame parameter |
CAL= |
QTIR |
uses POES quick calibration for faster image loads of POES data |
SF= |
YES |
automatically shows the frame prior to displaying the image |
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NO |
does not show the frame (default) |
By default, the upper-left corner of the image is positioned at the upper left corner of the frame. Use the keywords LATLON, LINELE, STATION and PLACE to specify a different image or frame position. Use the keyword MAG to blow up or blow down the image.
The predefined products specified in the predprod parameter are contained in the text files IMGDISP.CORE, IMGDISP.SITE and IMGDISP.USER. The .USER file overrides the .SITE file, which overrides the .CORE file. The .CORE file is supplied with McIDAS-X and should not be modified. You can, however, change the settings of its products and/or create your own products. To do so, copy the .CORE file from ~mcidas/data to your $HOME/mcidas/data or another MCPATH directory, rename it to IMGDISP.USER, then edit the existing products and/or add new ones.
The keywords TIME and RTIME select an image to display. They allow you to limit image selection to a specific time range. This is useful for choosing an image when new images are received frequently, such as GOES images during a Rapid Scan schedule. These keywords also allow you to spread out the scheduled image displays so scheduler activity is more evenly distributed throughout the hour.
The keyword CYCLE is most useful when used with the time scheduler to display the most recent image in a loop of frames. The image is displayed on the frame determined by the following formula.
frame=modulus((time-tol)/inc,numfra)+bfra
Time is the image time of the selected image, tol and inc are the time tolerance and increment values specified in the CYCLE keyword, numfra=efra-bfra+1, and bfra and efra are the range of frames specified in the CYCLE keyword. The frame determined with this keyword overrides the frame parameter
For example, if the command:
IMGDISP SAT/GOES-IR4K STATION=DCA CYCLE=1:00 1 5
is scheduled to run once an hour, the 13:00 UTC image in SAT/GOES-IR4K is displayed on frame 4, since time=13.0, inc=1.0, numfra=5 and bfra=1 (13.0/1.0=13; 13/5=2 with a remainder of 3; 3+1=4). The 14:00 UTC image is displayed on frame 5; the 15:00 UTC image is displayed on frame 1, etc.
If a similar IMGDISP command is scheduled to run every half-hour, but CYCLE=00:30 11 16, the 20:00 UTC image is displayed on frame 15, since time=20.0, inc=0.5, numfra=6 and bfra=11 (20.0/.5=40; 40/6=6 with a remainder of 4; 4+11=15). The 20:30 UTC image is displayed on frame 16; the 21:00 UTC image is displayed on frame 11, etc.
Specify a tol value in the CYCLE keyword only when the exact image times vary in a way that may result in one or more of the images being displayed in the frame following the desired one. This can happen when the selected image has an image time greater than the ending of the time range defined for the desired frame by the inc, bfra and efra values. The tol value adjusts the image time backward in the frame calculation equation so the image is displayed in the desired frame. For example, if you want to display each hour's "half-past" image (e.g., 00:30, 01:30, ..., 23:30) but the exact image times vary from 25 to 33 minutes past the hour, specify 1:00 for inc and a value of at least 00:04 for tol to ensure that the :30 to :33 images are displayed in the correct frames so that none of the :25 to :29 images overwrite :30 to :33 images from the the previous hour. The value specified in tol must be less than one-half the value specified for inc.
The REFRESH keyword runs the specified McIDAS commands after IMGDISP displays the image. You can use the notations (IMA) and (GRA) as parameters or keyword options in the commands. (IMA) is the number of the frame where the image is displayed. (GRA) is the number of the frame to display graphics produced by the commands. (GRA) is the same as (IMA) unless you specify a different beginning graphics frame number with the gframe parameter.
For example, to display new images in frames 1 through 5 but draw the corresponding maps and current surface temperature plots on frames 6 through 10, specify the following keywords:
SEQ=1 5 REFRESH='SF (IMA);EG (GRA);MAP GRA=(GRA) IMA=(IMA);SFCPLOT T NAV=C GRA=(GRA)' 6
If IMGDISP displays a new image in frame 1, the surface temperature plot and map are drawn on frame 6 because (IMA) is set to 1 and (GRA) is set to 6. If the new image is displayed on frame 2, the temperature plot and map are drawn on frame 7.
In satellite imagery, the latitude/longitude location of a pixel is determined by where the instrument is pointing. It is often the center of the field of view of the instrument, though the instrument vendor can define the geolocation any way they want. Regardless, in McIDAS it is assumed to be the center. For geographic projections, a pixel is just a point. So there is no notion of dimensionality, and it is again assumed to be the center. For users collocating pixels from different satellites, a larger issue is the viewing angle differences. They can be on the order of several pixels near nadir to tens of pixels away from nadir.
IMGDISP G8/VIS-CONUS
This entry displays the most recent image in dataset G8/VIS-CONUS on the current frame. The upper-left corner of the image is placed in the upper-left corner of the frame.
IMGDISP G8/VIS-CONUS.-1 STATION=STL TEXT='GOES-8 Visible Centered on St. Louis' 200 10
This entry displays the second most recent image in dataset G8/VIS-CONUS on the current frame, with St. Louis placed at the center of the frame. The default annotation at the bottom of the frame is replaced with the text GOES-8 Visible Centered on St. Louis in foreground brightness level 200 and background brightness level 10.
IMGDISP WV.1 STATION=STL
This entry displays the image in position 1 of the dataset specified in the predefined product WV or specified in the alias WV. The image is displayed with St. Louis placed at the center of the frame. If WV is a predefined product, it's defined in the IMGDISP.SITE or IMGDISP.USER file. If WV is an alias, it was created with the AKA command. This IMGDISP entry will error if WV is both a predefined product and an alias.
IMGDISP MKX_BREF1 ID=EVX MAG=2
This entry displays the product MKX_BREF1 that's defined in the IMGDISP.CORE file or modified in the IMGDISP.SITE or IMGDISP.USER file. The ID=EVX and MAG=2 keywords, which specify the NEXRAD station to select and an image blowup factor of 2, override the settings (if they exist) for those keywords in the predefined product. If an alias named MKX_BREF1 was previously created with the AKA command, this IMGDISP entry will error because you cannot have both an alias and a predefined product with the same name.
IMGDISP G8/VIS-CONUS.5 10 LATLON=35.5 100.2 PLACE=ULEFT MAG=2 GRAY=YES
This entry displays the image in position 5 in dataset G8/VIS-CONUS on frame 10, with earth coordinate 35.5° N, 100.2° W placed at the upper-left corner of the frame. The image is blown up by a factor of 2 from its original resolution and has the default grayscale bar at the bottom.
IMGDISP G8/VIS-GLOBE MAG=-7 LINELE=1400 2400 F PLACE=CENTER
This entry displays the most recent image in dataset G8/VIS-GLOBE on the current frame, with file (area) coordinate 1400, 2400 placed at the center of the frame. The displayed image is blown down by a factor of 7.
IMGDISP N14/GAC 1 DAY=#Y TIME=11:45 12:15 BAND=2 EU=POESVIS
This entry displays band 2 of the image in dataset N14/GAC with today's date and an image time between 11:45 and 12:15 UTC on frame 1. The enhancement table POESVIS is applied as the image is loaded. If more than one image in the dataset meets the specified time and date criteria, the most recent of those images is loaded. If none of the dataset's images meets the specified time and date criteria, no image is loaded.
IMGDISP STORM/IR.1 10 STATION=PIT REPEAT=4
This entry displays four consecutive images in dataset STORM/IR, with Pittsburgh placed at the center of each frame. The images in positions 1, 2, 3 and 4 are displayed on frames 10, 11, 12 and 13 respectively.
IMGDISP STORM/IR.1 20 STATION=PIT REPEAT=4 2 1
This entry displays four images in dataset STORM/IR, with Pittsburgh placed at the center of each frame. Because the position increment is 2 in the REPEAT keyword, the images in positions 1, 3, 5 and 7 are displayed on frames 20, 21, 22 and 23 respectively.
IMGDISP STORM/IR STATION=PIT PLACE=ULEFT ALL=1 10
This entry displays up to 10 images in dataset STORM/IR, with Pittsburgh placed at the upper-left corner of each frame. If STORM/IR contains more than 10 images, the ten most recent images are displayed in time order on frames 1 through 10. If STORM/IR contains 10 or less images, all images in STORM/IR are displayed in time order with the oldest image on frame 1.
NOTE: You can run either of the two commands below once an hour from the time scheduler (see commands SKE, SKL and SKU) to display the current hour's image in a loop of 6 frames. The only difference between them is that they use different methods of choosing the frame to display the new image. In the first example, the image is always displayed on the frame following the frame with the most recent image. In the second example, the image is displayed on the frame determined by the following formula:
frame=modulus(time/inc,numfra)+bfra
IMGDISP RT/GOES-IR LATLON=40 100 RTIME=0 5 SEQ=1 6
This entry displays the image in dataset RT/GOES-IR with an image time between 0 and 5 minutes after the current hour. The image is displayed with earth coordinate 40° N, 100° W placed at the center on the frame following the frame within the range 1 through 6 displaying the most recent image.
IMGDISP RT/GOES-IR LATLON=40 100 RTIME=0 5 CYCLE=1:00 1 6
This entry displays the image in dataset RT/GOES-IR with an image time between 0 and 5 minutes after the current hour. The image is displayed with earth coordinate 40° N, 100° W placed at the center on the frame determined by the following formula:
frame=modulus(time/1,6)+1
For example, the 17:00 UTC image is displayed in frame 6, the 18:00 UTC image is displayed in frame 1, etc. See the Remarks for additional details and examples.
IMGDISP RT/GOES-IR LATLON=40 100 RTIME=0 5 CYCLE=1:00 1 6 REFRESH='SF (IMA);EG (GRA); MAP GRA=(GRA) IMA=(IMA);SFCPLOT T SAT GRA=(GRA)' 11
This entry is the same as the one above, except that a surface temperature plot and map are drawn after the image is displayed. The image is displayed on a frame between 1 and 6. The temperature plot and map are drawn on the corresponding frame between 11 and 16 because the gframe parameter in the REFRESH keyword is set to 11. For example, if the image is displayed on frame 1, the temperature plot and map are drawn on frame 11; if the image is displayed on frame 2, the temperature plot and map are drawn on frame 12.
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