Highlighting a specific depth-range in a map is very easy to do with ReefMaster, whether it is to indicate areas of shallow water, or to define an area where you think the fish might be on a given day.

The process:
We need to generate a map where we can specify the colour for a specific range (or ranges) of depths. We do this by creating a User Map from the isobaths and contours that are generated by a map project.

1. Generate your map
Generate your map project in vector mode.Vector mode is important, because it gives us closed polygons for each depth range. We can then change the fill colour of these polygons in a user map, to highlight any areas we want.



2. Create a new User Map
In your map project, select an AT5 compatible palette for the depth colours, and choose the right-click menu option Add to map.../All components.../New user Map (you must be in the Contour View of the map project to see this option).

The new user map, before any editing:


3. Edit the colours of the depth-areas you want to highlight
In this example, we are going to highlight all areas with a depth between 9 and 15m.
Open up the Edit pane of the user map by clicking the Edit button at the top-right of the screen, and make sure that the isobaths group is selected in the drop-down group selector.



By default, isobaths are sorted by their depth, but if not you can sort them by clicking on either the Lower or Upper column headers.

Select all of the components within the target depth-range - in this case, everything from a lower value of 9 up to and including an upper value of 15.(To multi-select in the list, click the first required value, hold down the Shift key and then click the last required value).
Right-click on one of the selected items, and adjust the colour using the drop-down colour list.

The whole map, with depths between 9 and 15 metres highlighted in pink:


4. Export your finished map
That's all that is required to edit the map in ReefMaster. Now simply export the map, using the right-click menu and Write to file. Choose the Lowrance AT5 export format, and de-select the option Export background raster as this map is vector only (there is no harm in exporting a raster background, but it is not required when exporting a vector-only map that does not use transparency).
When you choose a destination folder for the export, you can choose root location of a memory card and simply put this card directly into your unit. Alternatively, you must copy the resulting at5.xml and Large.at5 files from your chosen directory to your unit's memory card.

Map shown on Lowrance HDS 5:


Detail of map shown on Lowrance HDS 5: