Geography Reference
In-Depth Information
Fill Patterns
For polygon and basic point symbol fills, the default is a solid. Q-
GIS has a range of other fill patterns you can choose from (includ-
ing hollow). Just click the pattern you want to use to select it.
More Properties
Let's finish up looking at a few more features of the vector Layer Prop-
erties dialog box before moving on to more advanced consideration of
QGIS. Some of the things we'll see here may not make too much sense
yet, depending on what class of user your are. Don't worry, we'll explain
as we go along and draw it all together.
General Tab
The General tab contains options and settings that are of all things—
“general.” First off we see that we can define a display name for the
layer. We did this in the previous example by right-clicking the layer
name and choosing Rename . That's the quick way to do it, but you can
also set it here if you like.
Scale-Dependent Rendering
QGIS supports scale-dependent rendering. Scale-dependent rendering
allows you to control when a layer is visible. There are a couple of
primary reasons why would we would want to do that:
• The layer is meaningless at small scales (remember, a small scale
covers a large area) because you wouldn't be able to see the infor-
mation. An example is displaying streets at the scale of our world_
borders layer. You wouldn't gain much information from such a
display.
• You have two versions of the data, one for small scales and one for
large. An example of this is a coastline. At a small scale (zoomed
way out), we don't need to display a lot of detail. In fact, such
detail is wasted and slows only the rendering process. You can
cram only so much information into a single pixel. As you zoom
in, you want the low resolution layer to switch off and another
higher resolution (more detail) layer to switch on.
If you choose to use scale-dependent rendering, you have to set the
minimum and maximum scales for the layer. This controls the visibility
of the layer. The scale for each setting is specified as a ratio of 1:[some
 
Search WWH ::




Custom Search