Map view Legend - ObjectVision/GeoDMS GitHub Wiki

User Guide GeoDMS GUI - map view legend

The upper part of the legend presents an overview with a zoomed out extent of the contents of the configured background layer. With the Toggle buttons ( ), the overview and legend view can be made (in)visible.

The Toggle buttons above switch the legend on and off as a whole. Its width is changed with two separate actions; there is no draggable splitter between the map and the legend.

action	effect
Ctrl-Shift-Left	the legend becomes 10 pixels wider, at the expense of the map. On a hidden legend, it makes the legend visible again
Ctrl-Shift-Right	the legend becomes 10 pixels narrower, in favour of the map. Narrowing beyond the minimum hides the legend altogether

The legend never becomes wider than its contents need, nor wider than the map view itself, so repeating Ctrl-Shift-Left stops at the width at which every layer control fits.

The same two actions are also in the pop-up menu of the map view, as Widen LayerControl and Narrow LayerControl, together with Copy LayerControl to Clipboard (Ctrl-G), which puts a bitmap of the legend on the clipboard. Right click on an empty area of the legend, below the layer controls, or anywhere in the map, to get them.

Since GeoDMS 20.18.0 these menu options name what they do and which keys work. From GeoDMS 17.9.5, when the width control was added, they were called Drag LayerControl Left (Ctrl-S) and Drag LayerControl Right (Ctrl-D). The keys changed in GeoDMS 18.2.1: Ctrl-D had become the shortcut for opening a table view, so pressing it in a map view opened a table instead of resizing the legend, and both Ctrl-S and Ctrl-D were then replaced by the Ctrl-Shift-Left/Ctrl-Shift-Right pair above. The menu captions were not corrected at the time and kept naming the two keys that no longer did anything, which is what made the options look broken.

example of a legend with three layers

The legend of the map view has two functions:

• to inform the user on the layers in the map view, including classification and palette and the value of a highlighted element in the map. In the example the colors are used to indicate each class. The two squares in each colored box indicate the layer is a grid layer. For polygon layers, two circles are used. For arc layers, a line symbol and for point layer the configured or default symbol (house) is used.
• to activate layer specific functionality of the layers in the map view.

Since GeoDMS 20.16.0 the selected (active) layer is easier to pick out: its layer control is drawn on a background 20 shades darker than the default, in addition to the highlighted caption bar it already had, and layer controls are framed by a three-pixel 3D border instead of a two-pixel one. Table header controls keep their two-pixel border.

With the right mouse click on a layer, a pop-up menu is activated:

The following options are available:

• Hide LayerControl for layer The layer is not visualized in the legend (e.g. background layers can be made hidden when exporting a legend). A right mouse click on the layer control on an empty area offers the option to make the hidden layers visible again.
• Set LayerControl Font: Three options are available for the size of the layer font in the legend. The default option is small. The user can set the font size to medium or large.
• Bring z-Position of Layer: The sequence of layers in the legend corresponds to the drawing order in the map view. This order can be changed with the four submenu options. Grid layers drawn above other layers are visualized transparently. Only the relevant submenu actions are enabled for the user:
  • To Top: The layer will be drawn above all other layers. In the legend, the layer is moved to the top. The option is only available in case the layer is not yet the top layer in the drawing order.
  • To Bottom: All other layers will be drawn above this layer. In the legend, the layer is moved to the bottom. The option is only available in case the layer is not yet the last layer in the drawing order.
  • Up: The layer is positioned one step higher in the draw order. In the legend, the layer is moved one place higher. The option is only available in case the layer is not yet the top layer in the drawing order.
  • Down: The layer is positioned one step lower in the draw order. In the legend, the layer is moved one place lower. The option is only available in case the layer is not yet the last layer in the drawing order. The sequence can also be adapted for dragging and dropping the layer.
• Remove layer: The layer is removed from the map view.

Based on the type of layer some additional layer specific options are available:

• Show Statistics on layer: presents a window with the same statistics as presented in the Statistics Window from the View menu.
• Classify ...: if one or more classifications are available for the data item in the layer, these are presented here. The user can select from the relevant classifications.
• Activate TreeItem of Layer Aspect: for each aspect the corresponding Tree Item with the thematic data and, if used, class breaks and aspect values can be activated in the TreeView. The submenus present the items with relevant aspects and items and their parents. With a left mouse click, the requested item becomes activated.
• Select SubLayer(s), (not for grid layers); the different style aspects used to draw a layer can be activated separately. The style aspects differ for the different layers types. Therefore, the set of submenu options differs per layer type. A checkmark indicates a style aspect is active (visible). For polygon and point layers, labels can be activated with the Select SubLayer > Label > Visible menu option.
• Zoom 1 Grid to 1 Pixel (only for grid layers): The layer is zoomed to the level at which each grid cell corresponds to one pixel. This is often the most elegant level to present a grid. For background layers this option can be used to zoom to the level at which the layer is rendered.
• Show Palette (only in case a palette item is used for visualization): This option toggles between showing and hiding the palette and label information in the legend of the classification scheme used for the data item. A checkmark before the menu option indicates the information is shown.
• Edit Palette This option activates the Classification and Palette editor to edit the classification/palette used to draw the layer.
• Copy Classbreaks (since GeoDMS 20.18.0, only for a classified layer): copies the class breaks of the layer to the clipboard, together with the color and the label of each class. The option is disabled for a layer that is drawn per unique value rather than per class.
• Paste Classbreaks (since GeoDMS 20.18.0): applies the class breaks on the clipboard to this layer, so that a classification made in one map view can be reused in another. Colors and labels are applied when the clipboard carries them; otherwise the standard color ramp and range labels are derived from the pasted breaks. The option is disabled when the clipboard holds no class breaks.
  • The class attributes that the GeoDMS generated for a view (under /Desktops/...) are overwritten in place. A configured or calculated classification is never overwritten, since it is shared with every other view that uses it: an editable copy is generated instead and the layer is re-themed onto it, with a message in the event log saying so.
  • A paste is refused when a class break cannot be represented by the value type of the thematic values, for instance a negative break on a uint32 attribute. Nothing is changed in that case.
  • The clipboard format is one class per line, ClassBreak;Color;Label, preceded by comment lines that record the source. It is read back tolerantly, so a table of class breaks pasted from a spreadsheet or from another GIS also lands: tab, semicolon and comma all work as separator, a header line is optional, colors are read as rgb(r,g,b), #RRGGBB or 0x00BBGGRR, and a bare column of numbers is a valid list of class breaks.

Since GeoDMS 20.18.0 a cell of the legend, and of the Classification and Palette editor, can be edited even when the data item behind it has a calculation rule. Before, the color dialogue and the label editor simply did not open for such an item, and ramping reported Cannot change derived data; try to copy the attribute and change the copied data.

That copy is now made for you, on the first edit:

• The configured item itself is never written. It belongs to the configuration and is shared with every other view that uses the same classification, so editing it would silently change those views too.
• Instead, the values the rule currently computes are copied into a new item under /Desktops/<desktop>/ViewData/, the layer is re-themed onto that copy, and the edit is applied there. The event log names both items.
• Every following edit of the same cell goes to that same copy, so a second color change continues from the first one rather than starting over from the configured values.
• Like every other edit made from the legend or the palette editor, the copy lives only for the current session. To keep it, put it in the configuration file; see classification.

What this does not cover is the number of classes: adding or removing a class resizes the class unit itself rather than one of its attributes, and no copy is made for that. Use Copy Classbreaks / Paste Classbreaks above to move to a differently sized classification, which generates a whole new one for the view.

A calculation rule that is a plain reference to another item, such as PenColor := BrushColor, is not copied: the edit reaches the referred item directly, exactly as it did before.