Size and weight is a big decision factor when you are trying to find the ideal camera for your needs.
In this section, We are going to illustrate Nikon L31 and Canon SD990 IS side-by-side from the front, back and top in their relative dimensions. Nikon L31 has external dimensions of 96 x 59 x 29 mm (3.78 x 2.32 x 1.14″) and weighs 160 g (0.35 lb / 5.64 oz) (including batteries). Canon SD990 IS has external dimensions of 98 x 62 x 28 mm (3.86 x 2.44 x 1.1″) and weighs 205 g (0.45 lb / 7.23 oz) (including batteries).
Below you can see the front view size comparison of Nikon L31 and Canon SD990 IS. Nikon L31 is 2mm narrower and 3mm shorter than Canon SD990 IS but it is also 1mm thicker.
Here is the back view size comparison of Nikon L31 and Canon SD990 IS.
Now lets look at the top view comparison of Nikon L31 and Canon SD990 IS.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Nikon L31 is significantly lighter (45g ) than the Canon SD990 IS which may become a big advantage especially on long walking trips.
Unfortunately neither Nikon Coolpix L31 nor Canon PowerShot SD990 IS (Digital IXUS 980 IS) provides any type of weather sealing in their body, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Compact Cameras with Weather Sealing
LCD Screen Size and Features
Nikon L31's 2.7" LCD screen is slightly larger than Canon SD990 IS's 2.5" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.