Overlay Vector data over built in CMAP Chart

[arnesr]

Is it possible to overlay vector data over the built in charts?  The built in charts appear to be vector data.  I tried naming my Atlas Description to what I believe to be the same name as the built in CMAP chart on my unit(New Eagle).  D=US Inland|M=C-MAP
 
That seems to have worked as no other map names load up, but my overlay data is covering up the included base map data when I load the chart.  I am trying to overlay points, but the map seems to be overlaying a large block of rectangular polygon area as a base layer.

I am able to overlay vector data on the social map by using the same Atlas Description and simply loading both maps on  one card.  I was hoping to accomplish the same thing, but utilizing the built in maps, but not sure if it is possible.

[fjordfischer]

Base maps are the lowest level in the device. As far as I know, you cannot overlay your own data directly onto these without overlaying the base map. This has to be the case, otherwise you wouldn't be able to use your own raster maps, for example. Consequently, the order of the elements from bottom to top on the device is as follows:
- Base map
- Raster maps
- Vector maps
- Device points, device lines

If you place any vector elements on the base map, they are integrated into a kind of tile structure, the basic color of which is the well-known olive, which I could only change with raster maps or by using polygon shapes, which then overlay the olive base tile.

The only thing you can do is "reconstruct" the base map using your own vector elements, provided you can find the data for it. There are many openly accessible data sources for this, especially in the USA.