1.
VIEW_HYD, main screen
VIEW_HYD.EXE is
the interactive display and analysis program for the hydrometeor data
files.Various modes and display criteria may be selected by the user. The
display may be controlled by mouse or by keyboard input. Single hydrometeor
data may be written to an ASCII file.
1.1
General Information on interactive graphics mode
1.1.1
User Interface
In each of the two
graphic modes (Run- and Stand-by mode) the following items allow user
interaction:
1.1.1.1 Buttons
Buttons are pushed
by moving the mouse cursor on top of the button icon and pressing the left
mouse button. Each button is assigned to a function key. Thus, buttons can also
be pushed by using the keyboard. The function key which has to be pressed to
push a particular button is displayed right next of the button icon.
1.1.1.2 Input
Fields
Input fields are
used to enter numerical values. If an input field is selected, the current
value of the field is highlighted. A cursor appears at the end of the input
line and the field may be edited.
"Backspace"
key |
Deletes the character left from
the cursor position. |
"Delete"
key |
Deletes the character right from
the cursor position. |
1.1.1.3 Diagram
Views
On the Main Screen
some diagram views can be seen. A diagram can be selected by
moving the mouse
cursor on top of the diagram icon and double click with the left mouse button.
On this action a separate window will be opened with a more detailed view and
depending on the kind of view also with more work options.
1.1.2
Run- and Standby-mode
Generally two
graphic modes are available:
1.1.2.1 Run-mode
In Run-mode
VIEW_HYD.EXE continuously displays data read from the specified V*.HYD file,
meaning that the current display is continuously updated. At start-up time
VIEW_HYD.EXE automatically
switches to the Main Screen in Standby-mode. First you have to load a valid
V*.HYD File by opening the File-Dialog. After the file is opened the user may change to the Run-Mode by
pressing the Run-Button (or F1-key on keyboard). The Run-mode may be stopped by
pushing the STOP button, which then toggles to be the RUN button. The current
display is set to Standby-mode.
1.1.2.2
Standby-mode
In Standby-mode
VIEW_HYD.EXE does not continuously read the data file and update the
display, but the
user may do menu selections, change parameters or just study the diagram
presented on the screen. Standby-mode may be left by pushing the RUN button,
which then toggles to be the STOP button.
On the upper half
of the screen five diagram views are arranged showing the following diagrams:
·
Rainrate versus Time
·
Drop Size Distribution
·
Velocity versus Diameter
·
Horizontal Velocity
·
Oblateness versus Diameter
Two further
diagram views show the front and the
side view of the currently displayed hydrometeor. In the middle of the screen a
virtual top view of the measuring area is represented. A window in the lower
left of the screen presents some information about the currently displayed
hydrometeor. Finally, a control panel is located on the right half of the screen.
It contains filter options and control buttons.
1.2.1
Control Panel
1.2.1.1 Buttons
button: STOP
In this mode
VIEW_HYD.EXE continuously displays data read from the specified data file,
meaning that drop
by drop is displayed and all the above mentioned windows are updated. In
Run-mode the cursor appears in hour-glass design. Run-mode may be stopped by
the STOP or by the QUIT button. If STOP has been pushed VIEW_HYD.EXE switches
to Standby-mode.
All the Main
Screen options are open to the user in Standby-mode, the STOP button
itself then
toggles to be the RUN button. If in Run-mode the end of the time window is
reached the button will be toggled to RUN.
button: RUN
The RUN button
activates the Run-mode. If RUN has been pushed, this button toggles to be the
STOP button. The windows in the Main Screen are reset, meaning that all figures
are cleaned.
button: STEP +
In Standby-mode
this button is used to step through the hydrometeor file entry by entry. Every
time button STEP + is pressed, the next hydrometeor is displayed and the
windows are updated.
button: RESET
In Standby-mode
the RESET button resets all windows of the Main Screen and in addition sets the
file position pointer to the start of the time window. The start time may be
defined via menu by the user, the default value depends on the setting made in
the Options-Dialog.
button: SCALE
The SCALE button
allows to toggle the scale of various displays (10 and 20 mm resp. 8 and 16 mm
in maximum size).
button: HELP
Displays this
document.
button QUIT
Terminates VIEW_HYD.EXE.
button DEFAULT
FILTER :
By pressing this
button, the default filter settings, which were saved under the section File à Options, were restored and displayed in the control panel.
list-control
HYDROMETEOR-TYPE:
By help of this
control you can change the type of hydrometeor you want to display in the
diagram windows. This is only possible, if you have classified the concerning
file.
Choosable types
are: all, not classified, rain, melting, snow, hail, manual, invalid.
1.2.1.2 Filter
Options
Filters allow the
user to sort out certain hydrometeors of special interest for being displayed.
At startup time default values are presented, they may be changed by the user.
In order to edit filter parameters, move the mouse cursor to the filter field
and press the left mouse button.
Name of Filter
Remark
Time window |
Determines the
time period for which data are to be displayed. |
Diameter |
Only
hydrometeors whose equivolumetric sphere diameter is within the given filter
limits will be evaluated. |
Velocity |
Only
hydrometeors whose velocity is within the given filter limits will be
evaluated. |
Oblateness |
Only
hydrometeors whose oblateness is within the given filter limits will be
evaluated. |
Pixel system A: |
Only
hydrometeors whose front view centre pixel is within the given filter limits
will be evaluated. |
Pixel system B: |
Only
hydrometeors whose side view centre pixel is within the given filter limits
will be evaluated. |
All this filter-settings and some additional settings could be permanently
saved in the Options-Dialog: (File à Options)
Tip Size: size of
optional rain-tip in mm
Window Title: user
customizable information which will be displayed in the window header
1.2.1.3 Area
Display Mode
The measuring area
could be viewed in 2 different modes:
It is possible to
change the viewing mode by checking the radio button while being in the running
mode.
1.2.2
Windows on the Main Screen
1.2.2.1 Measuring
Area Window
The Measuring Area
Window, placed in the middle of the VIEW_HYD.EXE - Main Screen represents a
virtual top view of the measuring area. The blue borders represent the user
defined limits. Via Filter Pixel System in the filter settings this area could
be shrinked. Hydrometeors hitting the border of the virtual measuring area in
the Sensor Unit are not evaluated by VIEW_HYD.EXE (nevertheless they are
contained in the V*.HYD files). This results in a decrease of the effective
measuring area for bigger hydrometeors.
An example is
given: For 10 mm diameter spheres, the effective measuring area is not around
100 * 100 mm² any longer but only around 90 * 90 mm². The size of the effective
measuring area for an individual hydrometeor is displayed in the information
window.
The Measuring Area
Window can be set to one of the following representation modes:
1.2.2.3
Information Window
Some information
on the currently visible hydrometeor can be found in the information window. In
addition some general information is displayed:
Time |
Time (Hour,
minute, second and milliseconds) when the hydrometeor encountered the
measuring area. |
Eq. Diameter |
Equivolumetric sphere
diameter in mm. |
Velocity |
Vertical fall
velocity in m/s. |
Oblateness |
Oblateness of
the drop. Note that side and front view is considered in the calculation of
oblateness. See "Oblateness versus Diameter" for further details. |
Hor. Velocity |
Horizontal
velocity is derived from the difference between the centre pixel position in
the first line and the centre pixel position in the last line of a particular
drop's shadow data. Horizontal velocity is composed of an absolute velocity
value and a movement direction. The velocity value is displayed in m/s. The
movement direction is given in relation to the distrometer's alignment and
denotes the direction where the drop comes from. (The graphiucs however
indicates where the drop goes to). The reading 10 m/s, 45° denotes a drop
moving towards cameras A and B. See "Horizontal Velocity" for
further details. |
Wind Sensor |
The horizontal
velocity measured by the wind sensor at the time given in the first line
(plus/minus 3 seconds) is displayed in the same notation as in the line above
the derivation of the distrometer measurement. If wind sensor
data are not available this is marked by ---------- |
Temperature |
The temperature
measured at the time given in the first line (plus/minus 3 seconds) is presented
in deg C. If temperature
data are not available this is marked by ---------- |
Type |
Type of
hydrometeor can manually be set in the “Front/Side View Full Screen” display |
Area |
This is the size
of the effective measuring area for the currently shown particle, which has
to be used for determination of rainrate and dropsize distribution. This
value depends on the size of the virtual measuring area in the Sensor Unit,
on the current filter settings and on the size of the hydrometeor. |
V*.HYD |
In this line the
hydrometeor data filename is given. The two numbers at the right hand side of
this line indicate the position of the presently displayed hydrometeor and of
the length of the file. |
1.2.3
Diagram Views on the Main Screen
Diagram views
serve two purposes. First, they show diagrams which continuously are updated.
Second, they can be used as menu buttons. Doubleclicking in one of the diagram
views brings up a full screen view of the selected diagram.
Diagram view: Rainrate
versus Time
The integration interval
used for calculating the rainfall rate for this diagram is not a time interval,
but a rainfall quantity. The diagram is updated each time total rainfall
exceeds a multiple of 0.1 mm. The rainfall rate over the past 30 minutes,
counted from the occurrence time of the most recent exceeding of the 0.1 mm
limit, is represented.
Diagram icon: Drop
Size Distribution
The diagram is
updated each time total rainfall exceeds a multiple of 0.1 mm, thus forming the
integration interval for calculating the drop size distribution. The diameter
class width is set to a value of 0.25 mm.
Diagram icon: Velocity
versus Diameter
This diagram shows
hydrometeor vertical fall velocity versus equivolumetric sphere diameter. A dot
is set for each hydrometeor at the corresponding (diameter, velocity) position.
The diagram is updated on each hydrometeor. In Run-mode this diagram is cleared
whenever total rainfall exceeds a multiple of 0.1 mm.
Diagram icon:
Horizontal Velocity
Horizontal
velocity is derived from the difference between the centre pixel position in
the first line and the centre pixel position in the last line of a particular
drop's shadow data. This difference in centre pixel positions is made visible
by drawing a "drop axis" into the front/side view of a drop. This
results in an approximation method to determine the drop's horizontal velocity.
It should be pointed out, that the horizontal velocity may be precisely
calculated, whenever the drop's views are divided into two identical halves. A
dot is set for each hydrometeor at the corresponding (velocity, direction)
position. The diagram is updated on each hydrometeor. In Run-mode this diagram
is cleared whenever total rainfall exceeds a multiple of 0.1 mm.
Diagram icon: Oblateness
versus Diameter
This diagram shows
drop oblateness versus equivolumetric sphere diameter. A pixel is set for each
drop at the corresponding (diameter,oblateness) position. The diagram is
updated on each drop.
Oblateness is
calculated by forming the geometric mean value of the two height/width ratios,
which can be computed from drop front and drop side view. In Run-mode this
diagram is cleared whenever total rainfall exceeds a multiple of 0.1 mm.
Diagram icons:
Front View / Side View
These diagrams
show the drop views as seen from each camera system. Note that "drop
axes", used for deriving horizontal velocity values, are drawn into the
drop views. These “drop axes” only approximately indicate the real axes of
bodies of revolution.