San Vicente map MapGazer – using transparency


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Using marks:
   Mark properties

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Using transparency

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Any map or mark that MapGazer displays can have variable transparency (that, show more or less of any other map or mark that it covers). In particular:

  • Base map – the primary map for a window.  It is drawn over a white “canvas”, therefore making it more transparent lightens (de-saturates) the map so that marks, etc., are more easily seen.  When the cursor is over the base map (and there is no overlay map, see below) you can press the ‘+’ or ‘−’ keys to increase or decrease the transparency of the base map in 5% intervals.  The base map is by default opaque (0% transparent).

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

  • Marks (tracks, waypoints, routes, scales, etc.).
    Marks are by default opaque (0% transparent).

  • Status information (e.g., current location of the mouse cursor, 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.

Adjust transparencies dialog

Adjust transparencies dialog

These can all have their transparency varied interactively by moving sliders in the Adjust 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 settings are independent and apply to all views, and are saved when MapGazer is closed.  The slider arrows also change transparencies at 5% intervals.  Press Reset to reset all transparency settings to their default values.

Mark transparencies

Individual marks can also have their transparency set, either by using the slider in the mark’s Properties dialog or moving the cursor over the mark (making it the active mark) and pressing the ‘+’ or ‘−’ keys (which increase or decrease the transparency of the mark in 5% intervals).

The transparency used to display a mark is the greater of its own transparency setting and the ‘master’ transparency setting described above; the master slider can therefore be used to hide all marks to allow a better view of the map alone.  In the case of a Route Waypoint, the Route transparency similarly overrides the Waypoint’s transparency.

When a mark is saved to a GPX file its transparency is saved along with its colour and other properties.

Overlay maps

To overlay a second map over the base map, select the Map → Add overlay map menu item.  Overlaying maps lets you see (for example) how geological information relates to topographic, or see street map information along with topography.  You can then vary the overlay map’s transparency using the Overlay map slider in Map → Map transparencies dialog, as described above, or by pressing the ‘+’ or ‘−’ keys when the cursor is over the map (these increase or decrease the transparency of the overlay map in 5% intervals).

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 Copyright © Mike Cowlishaw, 2014–2022, 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 2021-11-22 by mfc.