When the system displays some feature it should know how exactly it should be displayed: by which color, using which line width, etc. Such displaying characteristics are called displaying style of feature (or simply a style).
A set of elements making up feature style depends on spatial category of this feature, namely:
map symbol (graphic image using which the system will display the feature) for point features;
line style (that is, line width, its structure, color) for line features;
boundary line style, fill and hatch styles (displaying methods of feature insides) for area features;
font and color for texts.
There are five different types of styles in ObjectLand: fonts, map symbols, line styles, fill stiles and hatch styles.
These style types can be conditionally divided into three groups. The first group includes fill styles and raster map symbols which can be called raster styles since a raster, that is a point image, is its basis. The second group is comprised by the so-called vectorial styles. These are line styles, hatch styles and vectorial map symbols. These styles are united by the fact that vectorial image, that is, a set of line segments (or a set of more complex figures – circles, symbols) which makes up some graphic image is used as their basis. And the last group consists of fonts applied for displaying text features.
The user should take into account that the speed of displaying features considerably depends on selected styles. The highest speed is obtained when using styles supported by operating system. Most simple types of lines, fill and hatch styles belong to this group. More detailed information about system styles is given when particular types of styles are described. On the other hand, ObjectLand provides possibilities to create rather complex styles which permit obtaining more expressiveness in displaying maps but at the expense of increased time for displaying though. One of the possible solutions to this problem is to use simple styles in everyday work and use complex styles for more significant cases (for example, for printing maps).
