I found this I think any lake that sure in it are just showing the shoreline no detail on the lake like depths..
An incredible value in a sonar/GPS chartplotter combo with built-in mapping. Find fish, yourself, and your way, even in rain or fog, while marking spots and recording trails for return trips. All in this one easy-to-use and affordable sonar/mapping GPS package!
High-detail, 240Vx160H pixel, 4" diag. Film SuperTwist LCD display
16-level gray scale with GRAYLINE® for impressive target detail
800 watts peak-to-peak/100 watts RMS with depths to 600 ft.*
Compact 200 kHz Skimmer® transducer with built-in temp sensor and up to 60° of fish detection coverage
Space-saving case design with internal 12-parallel channel GPS+WAAS antenna
Built-in high-detail mapping of lakes, rivers, Great Lakes, and U.S. coastal waters with enhanced shoreline detail and nav aids
Saves up to 1,000 waypoints and event markers each
Up to 100 savable plot trails
10 international languages
Back-up memory
Sealed and waterproof
Full one-year warranty
as opposed to this with the hds7 that has the detailed lake maps with contour lines
HIGH-DEFINITION MAPPING
Built-in high sensitivity GPS antenna with superior time-to-location lock and precision position -- NMEA 2000® networkable
Optional LGC-4000 external GPS antenna module with high speed 5 Hz update rate available for custom applications -- NMEA 2000® networkable
Built-in base map including coastal shorelines, over 100,000 searchable lakes and water bodies, and highly accurate detailed shorelines and contours for over 4,000 lakes
Supports all Navionics® content including Platinum Plus, Platinum and Platinum Hot Maps on plug-and-play memory cards
Also supports all legacy Lowrance charts
LakeMaster® ProMaps surveyed lakes with high-detail depth contours.
Fishing Hot Spots® PRO with fishing points of interest.
NauticPath™ offshore/coastal maps, FreedomMaps™ land and lake topographic maps and MapCreate USA Series 7.
as opposed to this with the hds7 that has the detailed lake maps with contour lines