Graph tool
Graph tools
Graph tools displays a location-count graph for a line segment on the active image. For spectra images, a 'physical quantity' -count graph is displayed. The graph can be exported as a plain text file or a CSV file to be used by a spreadsheet program.
Usage
First, click the [Graph] button on the Tool bar, or select Graph in the Processing menu to activate the Graph Tools (the [Graph] button will be indented while graph tools is active). A graph Dialog will appear.
Draw a line on an image by dragging the mouse. A cyan line will be drawn on the image to show the region that will be graphed. When you release the left button of the mouse, the graph dialog will be drawn on the Graph Dialog.
For normal images, the vertical axis will be the count value, and the horizontal axis will be the distance from the stating point of the line segment in pixels. For spectra images, the horizontal axis will be the physical quantity.
To draw a new graph for new region, draw a new line segment on the image. The graph on the dialog will be updated to show the values on the new line segment. The old line segment will be displayed in gray.
To return to a graph to that of a region of a grayed line segment, click the gray line segment while pressing the [Ctrl] key.
To specify a rectangle parallel to a dispersion axis as the drawing region, drag the mouse on the image while holding down the [Shift] key. The graph will be displayed in the direction of the dispersion axis and the count value will be the average value of the orthogonal direction of the dispersion axis within the selected area. This function can be used to get a graph with a good S/N rate from an image with a bad S/N rate.
You can also adjust the presentation of the graph, print the graph, or export the graph as a text file within the graph dialog.
To hide the line segments on the image, click the [Hide marks...] button on the image Bar, and select "Graph" in "Type". To display the line segments, click the [Show] button in the Mark: section of the graph dialog.
To delete the line segments of an image, click the [Erase] button in the Mark: section of the graph dialog.
Tips
The dialog of Graph and Aperture Photometry and Rectangle Photometry, Astrometry can be non-displayed by pushing the F3 key. The dialog of Graph and Aperture Photometry and Rectangle Photometry, Astrometry can be displayed by pushing the F4 key. Also, the item of "Processing display" within the status bar display the display or non-display of these Dialog.
There is Dialog of non-display when "*" is displayed in the status of "ON". In this state, if the F4 key is pushed, dialog of Graph and Aperture Photometry and Rectangle Photometry, Astrometry is displayed, and if the F3 key is pushed, these dialog becomes non-display.
Graph Dialog
Information Area
The Information Area is located on the top area of the Graph Dialog. The information of the selected area is displayed here.
[X] This value is the x axis of the point selected within the Graph Area.
[Y] This value is the y axis of the point selected within the Graph Area.
[Count] This value is the count value (Brightness) at the point selected within the Graph area.
[Coordinates System or Spectrum Information] When there are coordinate information such as WCS and spectrum information within the FITS Header, the coordinate value and spectrum information is displayed here. When there is no coordinate information or spectrum information, this value will be blank.
[Select Area] The area selected on the image is displayed here. You can also change the area by entering the value of your choice. The selected area is shown as [ beginning point of line segment (X, Y) ] - [ end point of line segment (X, Y) ] for line segments and [ Selected area of X] , [Selected area of Y] for rectangular areas.
[Distance] This value is the distance between the point chosen within the graph area and the beginning point.
Graph Area
The numbers on the top and bottom of the left side of the graph area show the range of the displayed vertical axis. Dotted lines on the graph show the maximum threshold and minimum threshold of the gradation levels of the image.
Clicking or dragging on the graph draws a purple vertical line. The location of the corresponding pixel on the image, the count value, and the distance from the start point will be shown in the Information Area at the top area of the graph dialog. If the image is a spectrum image, the wavelength will also be shown. A cross will appear at the corresponding pixel on the image window.
[Horizontal Magnification] Edit Box and Spin Button
Adjust the horizontal scale of the graph here. If the scale is set at 1.0, the pixel distance of the image will be the same as the horizontal pixel distance of the graph.[Log] Check box
If this box is checked, the vertical axis will be displayed in logarithmic scale.[Show All]Check box
If this box is checked, a graph for each of the line segments of the image will be displayed in the graph area.[Other images graph]Check box
Checking show graph of all open images.[Vertical Scale] List
It is activated only if the image is a color image. Select the plane(s) that will be shown on the graph.[R, G, B] All of the R, G, B planes will be displayed on the graph.
[Brightness] The converted brightness value will be shown on the graph.
[R] Only the R plane will be shown on the graph.
[G] Only the G plane will be shown on the graph.
[B] Only the B plane will be shown on the graph.
[Settings...] Button
Click this button to adjust the scale of the graph. The 2D Graph Setting dialog will open.[Mark]
[Hide] button: Hides all the line segments on the image.
[Show] button: Shows all the line segments on the image.
[Erase] button: Erases all the line segments on the image.
[Print] Button
Print the graph by clicking this button.A "print" dialog will be displayed. Specify the printer and the paper size. Click the [Print] button to start printing.
The graph will automatically be adjusted to the size of the paper. Information such as the coordinates of the start point and the end point of the graph will also be printed.
[Output File...] Button
Click this button to export the graph as a plain text file (*.txt) or as a CSV file (*.csv).A "Save As..." dialog will appear. Set the file name and the exporting format, and click the [Save] Button.
The following formats are available:
For gray-scale images:
For color images :
For spectra images:
In a plain text format, the values are separated by spaces. In a CSV format, the values are separated by commas.
[Swap Axis]
If you are selecting the region of the graph by a rectangle, you can temporarily reverse the dispersion axes of the graph by clicking this button. If the current dispersion axis is set to the X-axis of the image, it's set to the Y-axis, and vice versa.[{triangle}] button
Pushing the {triangle} button can hide in the interface concerning the settings of the [Mark] and the [Print], etc. also, pushing the {reversed triangle} button can show in the interface concerning the settings.[2d Graph Settings...]
[Horizontal Scale]
[Auto] radio button: Automatically detect the maximum and minimum value on the line segment, and sets it as the range of the horizontal axis.
[Fixed] radio button: Choose this button to manually set the horizontal range. Set the range in the edit box below this button.
[Vertical Scale]
[Auto] radio button: Automatically detects the maximum and minimum value on the line segment, and sets it as the range of the vertical axis.
[Adjust Within Levels] Sets the gradation level of the image as the range of the vertical axis.
[Fixed] radio button: Choose this button to manually set the horizontal range. Set the range in the edit boxes below this button.
[Log Scale] check box: Check this box to display the vertical axis in logarithm scale.