I am new to RM and have just started working with side-scan mosaics. I currently have a lake map I have been making and I typically export this map as an AT5 Map with colour band shaded relief and depth highlight layer so I can turn the bottom hardness on/off. I would like to add my side-scan mosaics to the same memory card, but am not sure how to do this. I exported my mosaic as an AT5 Raster Layer, but I see the export produced a directory called ShadedRelief that has several _3DTexture_#.at5 files that are named the same as the files in my ShadedRelief folder from my map export (I assume this is the bottom hardness overlay). If I copy the new mosaic ShadedRelief folder to my memory card, it will overwrite files from the map. Is there a way to get both of these overlays on the same card in a way that my Lowrance HDS gen2 touch can independently turn them on/off ?

Unfortunately it is not possible to view multiple rasters on the same map, so the only way you could make this work would be to combine the rasters before running the IMC - which you could do by exporting the mosaic and shaded relief separately (to the same folder) and then running the IMC with this folder as the source for the raster process. The issue with this (apart from being more hassle) is that you would lose the ability to turn layers on or off on the unit. Also note that the IMC layers rasters with higher resolutions on top - in your case I would guess that you would end up with sidescan showing over the top of your shaded relief.

A better solution might be to export your depth map in vector format, with semi-transparent depth areas. These can then be displayed over your sidescan, and turned off if you want to get a better view of the mosaic.

Thanks Matt...that makes perfect sense. Do you know if there is any way to trim and save my side scan tracks in RM so that I can create a new shorter saved sidescan track and import it back onto my Lowrance unit (my current tracks are hours long). I know the Lowrance unit can save side scan recordings as .smf files in the field and then display these saved recording on the map using the "overlay structure" feature (can then choose to put a live view or saved recording...I assume this would be a way to control these independent of the bottom hardness vector overlay). Any way I can trim these side scan recordings and save as .smf files via RM or some other tool?

Just to follow up on this, I contacted Lowrance tech support and they said there is no software currently available that can trim side scan data and create .smf files from it. Guess Matt's suggestions above are the only options possible at the moment. Hopefully Lowrance will see the wisdom it making another option available to us some time in the future.