Maps
Offline Imagery
The core functionality of Bristol Maps relies on downloading imagery for offline use. A currated list of images are provided at various tide heights.
Image Layers
Layers
Various images of the same area can be overlaid on top of one another. The layers are numbered with the lowest number (1
) being the higher priority and will sit on top of other layers.
Transparency
When multiple layers are being used its possible to change the transparency of each layer from opaque to translucent. This can be very helpful when different images are take at various tide heights.
In the following example we have two images of the Nushagak bay which were taken at different tide heights. The image with the higher tide has priority 19
and the lower tide has priority 20
. The transparency on the higher tide is turned up which will allow the bottom image to partially show through.
The resulting overlay shows the shadow from the bottom image showing through. This can be helpful to understand the changes the tide will have on operable areas as the tide goes in and out.
Online Basemaps
Online basemaps are used as a bottom layer in which offline maps can be built upon. These require internet access. A basemap can be selected via the Settings
menu on the Navigation Page
Basemap Options
Satellite
This basemap displays currated Bristol Maps imagery and is helpful to view options before downloading them locally.
NOAA
This streams the modern NOAA charts.
Alaska High Res.
This is currated imagery provided by the State of Alaska and is a collection of older high res imagery. Some images may be several years old but provides excellent resolution.
Streets
This is the Open Streets map showing a non Satellite view displaying roads and highways.