Adding and editing concentration data

Analyzing and editing of concentration data primarily involves the panels in the upper two-thirds of the main GCLAS window. Data shown in graphs and tables are dynamically linked so that modifications to data in one panel are automatically reflected in the other panels. For example, if an estimated concentration value is modified in the tabular data panel, its position in the working graph is automatically updated, and vice versa. The curve-label panel also is synchronized with the working graph and tabular data panels, helping you tell which curve is which and showing you what data manipulations are enabled or disabled.

Using the overview graph and working graph to display curves and data points

On the top left panel is a tab with a graph icon . Left click on this tab and you will see an overview graph showing streamflow and concentration curves for the GCLAS year. When you see the overview graph, move the cursor into the overview window and press and hold the left mouse button, then drag the mouse to create a box that includes one of the peaks on the graph. When you release the mouse button, the working graph will be zoomed in. Repeat this procedure if you wish to see a different part of the GCLAS year in the working graph.

Note the shape of the symbols in the working graph:

• A rectangle means that the data point is for a representative sample (i.e. a sample whose concentation is representative of the mean concentration in the cross-section).
• An X means that the data point is for an estimated value.
• A triangle means that the data point is an unrepresentative (point or single-vertical) sample.

Note the two buttons at the bottom right of the panel. The one on the right, with the box-and-axis icon , lets you zoom the overview graph to the currently defined zoom rectangle. The one on the left, with the "home" icon , takes you back to the original (GCLAS-year-long) view.

The zoom features operate within the working graph panel also. Move your cursor into the working graph, then left click the mouse and drag to create a box. The working graph will be zoomed to include the area bounded by the box, and the overview graph will display a box showing the extent of this zoom. Additionally, a button on the toolbar immediately above the working graph with a "<<" symbol will become enabled. Left click on the "<<" (back) button to return to the previous zoom view. Now left click on the ">>" (forward) button to return to the newer zoom view. GCLAS allows you to go back to multiple previous zoom views and forward again.

If you wish to pan the GCLAS curve from the current zoom view, use the four arrow buttons on the toolbar to slide the working-graph frame (axes) vertically or horizontally. Or, use the arrow keys on your keyboard instead.

If you wish to go back to where you started, use the button at the extreme left of the toolbar, with the "home" icon , to take you back to the original (GCLAS-year-long) view.

If you wish to rescale the curves vertically to fill the entire working-graph frame, use the maximize scale toolbar button .

If you make a mistake when zooming in on the working graph or expanding the view to fit the axes, use the "back" button (<<) to return to the previous view and try again. (There is no "undo" command for this.)

Adding/Editing estimated values in the working graph panel

To add estimated values in the working graph panel, hold down the shift and control keys and click the left mouse button. The X and Y coordinates of the cursor in the working graph are continuously tracked and displayed in the lower left corner of the panel. The coordinate information is particularly useful when you're graphically adding estimated values to help ensure that estimates are added at or near the desired coordinates. If an estimated data point is not where you would like it to be, you can fix it in two ways:

• Remove it by clicking on the point with the left mouse button to select it, clicking on the point with the right mouse button to bring up a two-item menu, and left clicking "Remove Pt(s)."
• Modify its location by dragging the point vertically (up or down) in the working graph or by editing the time or concentration in the tabular data panel.

Left click on a data-point symbol in the working graph view panel to find and highlight the corresponding data-point entry in the tabular data panel, and vice versa. This feature can be useful when two points of interest plot very close to each other, too close to effectively use the mouse to select both; you can select one of the points on the graph, then use the table to select the other point.

Instructional prompts for basic working-graph tasks are given at the top of the panel.

Setting the default representation type of estimated values

When estimated values are added, they are assigned a representation type of cross section, single vertical, or point. GCLAS assigns a representation type of cross section by default; however, the default representation can be changed for the duration of a GCLAS session by choosing a different representation from the Options menu as shown below:

Left click on the radio button next to a representation type to change the default representation to that type. The change in default representation type will affect only those estimated values that are added subsequently, and then only for the current GCLAS session. Any estimated values that were added prior to the change will retain the representation type assigned at the time they were added. If you wish to change the representation type of an estimated value that already has been added, you must follow the instructions given below for editing data in the tabular data panel.

Editing data in the tabular data panel

The tabular data panel displays in a tabbed folder format in which different types of data and data from different sites are organized under separate tabbed tables.

One of these tables has a tab with the concentration file name followed by the parameter code for the constituent of interest. This table (referred to as the "GCLAS table" hereafter) contains both concentration data and streamflow data (machine interpolated, if necessary), and it is editable. When a constituent such as sediment is selected for working a record, subcolumns for cross-section (box) coefficient and the values that result from the application of the coefficient are added to this table, and the curve that is plotted will reflect the coefficient-adjusted column.

The other table contains streamflow data contained in the original card-image file, and its tab label reflects the actual name of the file; this table is for reference only and is not editable. To switch between tables, left click on the appropriate tab.

The GCLAS table contains a wealth of ancillary information associated with each data value. Some of this ancillary information is placed in the table as default entries when external files are read in and the GCLAS year is created. Most of these entries, however, can be changed to match your knowledge of actual conditions or can be set to accurately represent added data. Some of the columns in the GCLAS table are self-explanatory, but others, especially those that have pick-list options, require some description.

Under the Sample spanner heading:

• Representation (4 options). Cross section, point, single vertical, unspecified.
• Hydro Condition (7 options). Choices for stable flow at various magnitudes or for rising or falling stage.
• Collector (4 options). Hydrologist, observer, automatic, unspecified.
• Hydro event (12 options). Wide range of choices, including hurricane, earthquake, volcanic activity (as well as routine sample).
• Method (7 options). Includes equal discharge increment (EDI), equal width increment (EWI), pumped, unspecified, etc.
• QA Type (12 options). Replicate, duplicate, composite, spike, etc.

Under the 80154 (or comparably named) spanner heading:

• Remark (3 options). Trace shape, transport curve, other.
• Usable (check box). Important! This column allows you to declare a value unusable (by unchecking it). Values marked as unusable will continue to be displayed in the graphs, but will be ignored for all other purposes.
• Status (4 options). Presumed OK, accepted, rejected, other lab-related codes.
• Type (2 options). Field or lab.
• QA Type (12 options). Same options as under Sample spanner heading

Data in the GCLAS table can be manipulated in three ways:

• Numerical data can be changed by double left clicking on the table cell to enable editing. Position the cursor with a single left click, then delete, backspace over, or type in new numbers. Double left click to highlight all data in the cell to delete or type over everything. Then hit the Enter key to apply the change.
• Date and Time data can be changed in a fashion similar to other numerical data, however; there are some special editing characteristics associated with these field. See the quick reference section on special functions for editing dates and times.
• Comments or qualifiers can be changed by double left clicking to display a pick list and then selecting an entry from that list.
• Check boxes can be checked or unchecked by left clicking twice and then hitting Enter (Currently, the Usable column is the only one that contains check boxes. Unchecked entries are ignored in plotted curves and in load computations.)

As you change concentration or discharge values in the table, the curves and symbols in the working graph and the overview graph will reflect the changes accordingly.

Ancillary information may be important for some analyses, but it can be a distraction for others. Consequently, GCLAS was designed so that you can toggle between detailed and less-detailed views of the data by left clicking on major or minor table headings in the tabbed tables.

For additional data-viewing flexibility, you can reorder columns by dragging a column heading to its desired location within the table. You can also use the scroll bars to navigate through the table and the slider tool to put space between rows for easier viewing.

Using the curve label panel

The curve label panel displays information about what data are being displayed and which elements of the display can or cannot be manipulated. It also is used to change settings that enable or disable certain editing features. Its capabilities are best described by describing its many individual features.

Curve label itself:

• Color coding of curve labels corresponds to that of the curves themselves.
• Line through label name indicates that the corresponding data set is not displayed on the graph.
• Order of curve labels in the list indicates and controls the order in which curves are plotted; the curve listed first is plotted on top. Reordering curve labels changes the plotting order. This can be done by left clicking on a label and dragging it. (The cursor will change to a different symbol while the drag is happening.)

Symbols on icons to the left of the label:

• Circle and slash means that the curve will not respond to manipulation with the mouse. Absence of the circle and slash means that mouse manipulation is enabled.
• Red ("active") dot means that the curve representing the label is the active curve.
• I-beam symbol means that the curve is editable. Absence of I-beam means that the curve cannot be edited.
• Point symbol (an open circle in the lower-right corner) means symbols are displayed on the working graph.
• Line symbol (a forward slash in the upper-right corner) means lines (curves) are displayed on the working graph.
• Carets indicate whether a curve can be or has been moved. A slash through the caret indicates that the curve has been moved but cannot presently be moved.

Pick-list entries:

• Can mouse enables or disables "mousing" (data-point manipulation with the mouse) for the curve of interest. For example, you might wish to disable mousing of a streamflow curve so that you can better manipulate a concentration curve if the two curves are close together.
• Can move enables or disables curve movement with the mouse. When enabled, the curve can be moved by pressing the control key and simultaneously left clicking on a point on the curve and dragging with the mouse. (The middle mouse button also works on UNIX machines).
• Reset move restores the curve to its original position (and thus serves as an undo for a move).
• Can edit allows a curve/data set to be edited.
• Hide curve removes a previously displayed curve from the working and overview graphs.
• Show curve displays a previously undisplayed curve on the working and overview graphs.
• Delete curve eliminates the entry in the curve label list (so you'll need to re-create the curve from the file tree if you wish to bring it back).
• Draw lines plots a line between the points, colored to correspond to the color of the curve label.
• Draw symbols plots the measured data points as triangles and rectangles and estimated data points as X’s.
• Curve properties will produce a dialog with fields for changing the curve color and the size of symbols. This is not yet available.