Themes in ArcView are displayed as either points (such as showing the location of a village, building, or pest trap, depending on the scale), lines (such as roads, rivers, or contours), or polygons (such as forest reserves, districts, countries, or land parcels).
In our current View we have themes that are lines (such as "Iganga-roads_50000" and "Iganga_topog.shp"), polygons (such as "Uganda_district.shp" and Iganga-urban_50000"), and points ("Lews_livestock.shp").
As we have seen, each theme in the Table of Contents has a small box to its left. Checking a box draws a theme in the right side of the View, while unchecking the box redraws the map on the right without that theme.
You check or uncheck a box by placing your cursor over it and clicking on it once.
Let us see how this works. Uncheck all the themes so that your view looks like this:
The order in which themes appear in the Table of Contents is important, because themes listed at the top of the Table of Contents are drawn over those listed below them. Thus, a theme that is at the top of the Table of Contents and also displayed as a polygon on the map will cover over any theme listed below it. Consequently, a smaller polygon should be higher in the Table of Contents than a larger polygon if you want to see them both displayed at the same time.
In contrast, a theme that is at the top of the Table of Contents and displayed as a line (such as a river or road) or a point (such as a house) on the map will only cover over a limited portion of any theme listed below it. Thus, such themes should occur above polygons in the Table of Contents.
In our Table of Contents, click on the boxes for the themes "Uganda_district.shp," "Lews_livestock.shp," and "Uganda_rivers.shp" so that check marks appear in the boxes next to these theme names and these themes appear on the map in our View.
(The points in the theme "Lews_livestock.shp" are from a study of livestock raising in Uganda for the Livestock Early Warning System conducted by the Department of Rangeland Ecology & Management, Texas A & M University; the points represent households owning livestock.)
We can see all the themes because the polygon theme, "Uganda_district.shp," is at the bottom of the Table of Contents.Now drag the theme name "Uganda_district.shp" with your cursor to the top of the Table of Contents. Now we only see the districts, because polygon themes cover point and line themes.
Drag the theme "Uganda_district.shp" back to the bottom of the Table of Contents.
Thus, it is best to have polygon themes at the bottom of the Table of Contents and points and lines above them so that the polygons will not cover the points and lines in the map displayed on the right.
Similarly, you should have smaller polygon themes higher in the Table of Contents than larger ones.
Uncheck the boxes for the themes "Lews_livestock.shp," and "Uganda_rivers.shp" so that they are not displayed on the map. Check the box for the theme "Iganga_subdist.shp" so that it appears on the map; this theme shows the boundaries of subcounties in Iganga. We can see both polygon themes because the smaller one is listed higher in the Table of Contents.
Here is another example of the value of superimposing one polygon on top of another.
Uncheck the box next to the theme "Iganga_subdist.shp" and check the box next to the theme "Uganda_water.shp" so that it appears on the map. Now we can see the water bodies in Uganda, which are superimposed over the map of the district boundaries. 
Displaying the water bodies theme on top of the districts theme provides a better perspective on the map.
But what happens if you want to display two polygons that cover exactly the same area?You can change the shading of polygons to make one of the themes transparent. We will learn to do that in Step 6.
Right now we can only see the outlines of features on our map. We want to be able to identify the characteristics of the features on our maps.