Create Fills for Closed Polylines

Use the Map Tools > Create Fills for Closed Polylines menu option (POLYGEN GX) to add a polygonal area group to a line interpretation group. This is intended for drawing interpretations on a map. A line group is first drawn to mark the location of interpreted faults and contacts. The polygonal group added to this line group will then contain the polygonal areas enclosed by all the lines.

There are two dialogs in this tool. The second dialog is only displayed if a legend is requested.

Create Fills for Closed Polylines dialog options

Line group to process	Select an existing "View/Group" that contains the line components of an interpretation. This group may contain lines, polylines and polygons. Polygons should not be filled, otherwise the final map will contain overlapping polygons.
Use colours or patterns	The new created polygons may be filled by solid colours, patterns, or coloured patterns. Use patterned fills if your interpretation will overlay an image.
Number of units	Specify the maximum number of different discrete units to create for the interpretation. This number will be used to determine the number of units in the interpretation legend. The colours and patterns of the new polygons will be selected from up to this many separate units. If there are more polygons than units, we will cycle through the defined number of units repetitively.
Legend?	Specify "Yes" if you would like a unit legend added to the right side of the map. If you add a legend, the next dialog box will appear.

Legend dialog options

Legend box size (mm)	Each unit in the legend will use a square box of this size to show the reference colour and pattern.
Box separation (mm)	This is the vertical gap to leave between boxes.
Legend text size (mm)	This is the size for descriptive legend text for each unit.
Number of legend text lines	Specify the number of legend text lines that you will need to describe each unit in the legend.
Maximum units / column	The legend can be drawn in multiple columns where this is the maximum number of units for each column. If you leave this blank, the legend will be drawn as a single column.
Column separation (mm)	For multiple column legends, this is the width of each column.

Application Notes

This GX is used for creating interpretation layers on a map. You may have an image of some kind displayed on a map and you would like to draw a geologic interpretation of the image. The following steps can be followed:

1. Create and edit a new group to hold the line components of the interpretation. Line components may include lines, polylines and unfilled polygons. For example, you may begin by drawing all interpreted fault lines using the same fault line pattern. You may then add lines that mark the locations of interpreted contacts. When you are finished, the combination of fault lines and contact lines will visually define discrete polygonal areas on the map. The next step will create polygons from these lines.

2. Run this GX (POLYGEN) to create a new group to hold the polygon components of the interpretation. An exclusive polygon will be created from all the lines in the line interpretation group. Each polygon is assigned consecutively to a separate unit, which will have a default colour and/or pattern.

3. If a legend has been drawn, you can now customize the interpretation legend. Edit the new polygon and select each legend box and modify the colour and/or pattern attributes as desired. Do this for all legend units, and remove any legend units that are not required. It is important that each unit have a unique combination of colour and pattern. Modify the descriptive text as desired. It is a good idea to save the map changes at this point.

4. You will now assign the defined legend attributes to the interpreted polygon units. Select the "eye-dropper" icon on the edit tool-bar and select the attributes from the legend unit you would like to use first. The "paint-brush" icon can now be used to apply this attribute to the polygons that correspond to this unit. To select a unit, click inside the polygon to first mark the polygon, then click again to assign this attribute to that polygon. If the wrong polygon is selected, click the right button (or press "Esc") to select a different polygon. Continue this process for all units of the legend. When you are finished, all polygon units on the map should be assigned to a legend unit.

5. To edit the interpretation, either to add more units, more interpretation lines, or to move lines and units, select and edit the original line interpretation group. Add whatever lines are required. To change an existing line, first draw the new line then delete the existing incorrect line. When you are done, select "End editing" and click the right mouse button with the cursor located somewhere in the selected line interpretation group. A "Re-generate polygons" option will appear at the bottom of the pop-up menu. When you select this, the polygon group will be updated to reflect the new interpretation lines. The update process will make a best-guess for the attributes of any new polygon based on proximity to the centroid of the original polygons. If the assigned attributes are not correct, you can go to step 4 to re-assign the attributes from the legend.

6. If you need to change any legend attribute, select and edit the polygon group, select the legend box to modify, make the changes. You will see that the "Shared attribute" is checked in the attribute dialog (if it is not, check it). When you press the OK button, all attribute on the map will change to the new attribute.

   Be careful not to change the attribute the same colour/pattern as any other legend unit. If you do, you must select one of the legend units, modify its attributes to be different, and save the attribute with the "Shared attribute" not checked. You can then reassign the interpreted units from the new legend as described in step 4.