San Vicente map MapGazer – Using transparency


Download MapGazer

Getting started

Using marks:
   Mark properties

Using the Scale

Using icons

Using transparency

General settings

Getting maps

Elevation data

Coordinate formats

GPX files

Command line


MapGazer windows have a base map, which is the primary map for that window. Four types of information can be overlaid on the base map:

  • Overlay map – a supplementary map, usually chosen to allow additional information to be displayed, for example a geological map overlaid on a topographical map, or a topographical map overlaid on a street map. See below for an example.
    The default for overlay maps is 50% transparent.

  • Marks (tracks, waypoints, routes, or areas) – see Using Tracks, etc.
    Marks are by default opaque (0% transparent).

  • Scale (the Scale bar usually shown at bottom-left of a window) – see Using the Scale.
    The Scale bar is by default opaque (0% transparent); the background of its distance label uses the same transparency as status information.

  • Status information (e.g., current position of the mouse, shown at top left, also map copyright and zoom level, shown at bottom right) – see Settings.
    Status information is displayed as black text shown on, by default, a 20% transparent white background.

<i>Transparencies</i> dialog

Transparencies dialog

All four overlay types can have their transparency varied interactively by moving sliders in the Transparencies dialog. To open this, select the Map → Map transparencies menu item (also available from the map pop-up menu), or press the ‘t’ key. The four settings are independent and apply to all views, and are saved when MapGazer is closed.

You can also change the transparency of the overlay map directly by pressing the ‘+’ or ‘-’ keys (which increase or decrease the transparency of the overlay map in 5% intervals).

The slider arrows also change transparencies at 5% intervals. Press Reset to reset all transparency settings to their default values.

Overlay maps

To overlay a second map over the base map, select the Map → Add overlay map menu item. You can then vary its transparency using the Overlay map slider in Map → Map transparencies dialog, as described above. Overlaying maps lets you see (for example) how geological information relates to topographic, or see street map information along with topography.

You can try this for yourself by using the provided SampleMap as the base map and then adding the SampleGeology map as the overlay map.

An active overlay map can be changed using Map → Change overlay map or removed using Map → Remove overlay map. The overlay map options are also available from the map pop-up menu.

Please click here for an animation (13MB) of varying the transparency of a geological map overlaid over a topographical map. Below are two ‘stills’ from that animation.

Geological overlay 80% transparent

Geological overlay 80% transparent

Geological overlay 40% transparent

Geological overlay 40% transparent

MapGazer and these web pages were written by Mike Cowlishaw; Please send me any corrections, suggestions, etc.
All content © Mike Cowlishaw, 2014–2017, except where marked otherwise. All rights reserved. The pages here, and the MapGazer program, are for non-commercial use only. Privacy policy: the Speleotrove website records no personal information and sets no ‘cookies’. However, statistics, etc. might be recorded by the web hosting service.

This page was last updated on 2017-01-13 by mfc.