Manual Exposure Mode
A correct exposure of a landscape shot is very important. Even though modern digital cameras features advanced algorithms to calculate the right exposure, they still may fail some difficult conditions. Manual exposure mode in these conditions helps a lot in order to achieve correct exposure. Built-in GPS
Landscape photographers frequently turn back to a point where they had shoot a specific shot in different weather and light conditions. Recording these locations via GPS will help you find the exact spot later easier. 25 mm - Good Wide Angle Coverage
Even though there are very good examples of landscapes photos taken with tele lenses, most of the landscape photos are taken with wide angle lenses.
Average Resolution Sensor: 16.0MP
Nikon S9900's 16.0MP resolution is not ideal for landscape photography but you can still achieve large prints with good framing and technique.
No Manual Focus Mode
Manual focus in landscape photography is very useful in order to have a sharp image and minimize the areas that are out of focus. Autofocus may not consistently give you the best results. No RAW shooting capability
RAW files contains much more color information compared to JPEGs, and gives you more room for post processing without significant quality loss. They provide wider dynamic range and option to recover shadow and highlight clipping to some degree. Small 1/2.3" (6.17 x 4.55 mm) sensor
Nikon S9900's small sensor struggles in low light situations compared to larger sensors. No Environmental Sealings
Landscape photographs are taken outdoors and you should be prepared for all kind of weather conditions.