As you know printed maps have now been virtually replaced by GPS devices. However, electronic devices are not foolproof, and GPS can sometimes fail.
There can be many causes, deep gorges, no signals, low battery etc. So I recommend taking a printed map on your trek. For my Rara Lake Trip I took a printed map from The Himalayan Map House in Thamel. You can check my Rara lake trip report. You can buy this map in any retail store in Thamel or can order it online before you get to Nepal.
But for your reference and to assist, here is an online version of the Rara Lake map. Many thanks to cartographers from The Himalayan Map House for this online map, and very special thanks to Pradeep, who embed this with software to make it more use friendly.
You can use the navigation tool to zoom in and out and navigate the map. Also you can double click to zoom then click and drag to view the map.