building a map

You can communicate complex information more effectively using maps than with tables or lists, because maps take advantage of our natural abilities to distinguish and interpret colours, patterns and spatial relationships. Choosing how to represent your data on a map may well be your most important map-making decision. Symbolizing your data involves choosing the colors and symbols that will represent features.

In this lesson you will build up a map of the Soth East Asian region, using symbols to show the relative populations of some of the major cities. Before you begin you should add a couple more themes to make your map a little more visually pleasing. You have already learnt how to add themes, if you have forgotton go back to refresh your memory, then return here and proceed with the lesson. Add the Rivers and World30 themes to your view and edit their properties to name them Rivers and Ocean, respectively. Display all of the new themes in your view by clicking the check boxes next to their names. Notice that the Oceans theme covers all others. You need to place this theme at the bottom of the pile of themes by clicking and holding the left mouse button on it, then dragging it under the other themes before releasing the mouse button. Now zoom in on the SE Asian region using zoom.

To control how each theme is drawn in a view, and therefore how your map appears, you use the Legend Editor. The Legend Editor lets you choose:

If you want to classify the theme''s features, or display all the features with the same symbol.
The attribute with which the theme''s features will be classified
The method of classification
The colour scheme for the classification
The symbols used to display each class of features
How each class of features will be described in your views table of contents.
You can also use the legend Editor to change how themes are displayed by choosing the symbols you want to use:

Fill symbols (for areas, eg. solid colour, diagonal lines, hatchures, outlines)
Pen symbols (for lines, eg. solid, dashed, wide, narrow)
Marker symbols (for points, eg. squares, diamonds, triangles)
Colors (background, foreground, outline colors)
You will use the Legend Editor to provide a unique color to the countries and to display the cities theme with the size of the city symbol representing that cities population. You can bring the legend editor window up in one of two ways. Either by clicking the button on the toolbar with the theme of interest selected, or by double-clicking on the theme in the Table of Contents of the View window.

First you will display each of the countries with a unique colour so that they can be more easily discerned. Double click the World Countries ''94 theme to bring up the Legend Editor. From the Legend Type drop down menu select Unique Value. From the Values Field drop down menu select the Name attribute to be the one used to colour the countries. Now click the Apply button. You should notice that your view changes, it is now easier to distinguish between countries.

Close the Legend Editor. Notice also that in your views table of contents the legend contains the names and associated colour of all the countries in the world. This takes up a lot of space and is of no real interest at the moment so you should temorarilly hide the legend. Select Theme - Hide/Show Legend from the main menu bar and the Legend will be removed from the display. While your doing this you can also hide the legends for the Ocean and Rivers themes.

Next you will edit the World Cities theme to create a legend which shows the cities symbol size as proportional to its population. Double click the World Cities theme to bring up the Legend Editor. From the Legend Type drop down menu select Graduated Symbol. Now we want to base the symbol size on the population of each city so from the Classification Field drop down menu select the Population attribute to be the one used to set the symbol size.

ArcView then calculates a new legend for you by classifying the population attributes of the World Cities theme into 5 classes. The classification scheme (the method used and number of classes derived) can be changed by clicking the classify ... button. For now you won''t bother but keep this in mind for later. You can, and will, input the values and legend labels interactively simply by clicking the mouse button in the relevent field and editing the text that appears there. Now go ahead and change the Value and Label fields to read;

Value Label
-99 - 100000
100001 - 1000000
1000001 - 3000000
3000001 - 5000000
5000001 - 23620000 < 100,000
100,000 - 1 million
1 million - 3 million
3 million - 5 million
> 5 million

The symbol you are using is a simple filled circle. It may be better to change this to make it easier to see differences between cities. Double click the symbol icon in the Symbol box located near the bottom left of the Legend Editor window. The Marker Palette window will appear. Double click on the symbol you wish to use and it will be reflected in the Legend Editor window immediatly. You can also change other characteristics of the symbol you are using by selecting one of the other icons . Do as you wish then close the Marker Palette window, click the Apply button in the Legend Editor window, then finally close the Legend Editor Window.

Your view should no be similar (although your symbology for the cities might differ) to that in Figure ii. You have created a simple map which expresses a cities population in the size of the symbol used to represent it. It may however also be useful to label some of the cities. In the next step you will be shown how to add labels to your view.

ArcView has a tool which labels a feature (ie. polygon, line or point) with the first record in the attribute table. The attribute tables for the World Cities theme are logically ordered by city name. So we can use the label tool to label some of the cities displayed in your view. Highlight the World Cities theme, click the button and click on a city, at the position where you want the label to start. The city will be automatically labelled with its name (the first record in the attribute table). You can label as many cities as you like. Notice that when you add a label, it is framed by four handles.

Labels can be moved by clicking the Pointer Tool and clicking once on the label you wish to move. Handles appear around the label to show that it is selected. Now adjust its position but don''t move it to far as you may end up labelling the neighbouring city with the wrong name. You may think that some of the labels are too big. By dragging on a lables handles with the Pointer tool you can also resize the label. When you are finished working with the labels, you can deselect any labels that are selected by clicking on the map with the Pointer tool, anywhere where there is no label.

If you want to add text for any reason you can use the Text tool. Simply click the button then click in the view where you want the text to appear. A window will appear in which you can type in your text. Once you have typed the text click the OK button and it will appear on the view. As with other labels you can use the Pointer tool to move and resize the new label. Use this tool to add a label for the Pacific Ocean.

In the next lesson you will learn how to create the final map and make it ready for output. Before moving on make sure you have in your view displayed the SE Asian region showing, countries, cities (with symbols representing population), rivers, the ocean and some city names. Your view should essentially be very similar to that in Figure iii. Make sure and save your project by clicking the button or by selecting File - Save Project from the main menu. Then proceed to the next lesson.

Creating a Map Layout
You have now set up your view as you desire (produced in the last lesson). Now you want to produce output with a title, scale bar, legend, north arrow and some descriptive text. All the elements you need to create a useful map. This is called creating a layout in Arciew. A layout allows you to assemble all the components you want to appear in a map, arrange them together to create the design you want. You can go about this in two ways. Either by using one of ArcViews built in templates or by designing the layout from the very begginning yourself. In this lesson you will use both methods.

Using a Template
Make sure your view is as you want it to appear in your map (should have been completed in the last lesson), then select View - Layout ... from the view menu. This will bring up the Template manager. This allows you to create map layouts automatically using previously saved layouts called templates. Click the landscape template and the OK button.

ArcView automatically creates a layout that includes your map of SE Asia, a legend, a title, a north arrow and a scale bar. To navigating around the layout window use the same buttons and tools you would for the view window. By default, ArcView uses the view''s name as the title for the layout. As your map is no longer a world map, you should change the title. With the Pointer tool selected, double click the title. In the dialog that appears, delete the existing text and type a suitable title. Click OK and the title changes. Make your layout neater by moving and resizing with the Pointer Tool but don''t spend too much time doing this as you will shortly be deleting this layout and starting from scratch.

Quite easy really. However, you are now going to make the layout from scratch so delete what you just made. However, remember how to do the above as it may be all you require for some tasks in the future. Select the Layouts icon (shown in Fig. i.) from the project window contents. Highlight the Layout name, if it is not already highlighted then select Project - Delete from the main menu bar. When prompted to confirm deletion, do so.
Fig i. Layout icon from the project window


Creating a Layout
Although the above method is quick it does not provide much flexibility. For instance you may want a completely different format which shows more than one map. For this reason you must learn how to create a layout from scratch. You will create a new layout much like that you just deleted but with the addition of some descriptive text.

Make the project window active and then select the Layout Icon (Fig i.). Click New and an empty layout appears on the screen. Before you do any work on the layout you have created you need to set up some properties, such as the paper size you intend to use. Select Layout - Page Setup from the main menu. From the page size list, choose the paper format to use, in this case A4. The paper units should automatically change to cm. It is also possible to specify the margins of your layout. Margins are displayed as blue lines around the edge of the layout, they are to be used as a guide and wont actually be printed. However, for the moment don''t worry about this. Now change the page orientation to landscape and click the OK button.

It is also useful to set up the layout grid. By default, a layout is covered by a grid of dots, to which components are automatically snapped when you add them to the layout or move them around. The grid helps you line things (position) up. To change the grid spacing or to disable the snap to grid option (which means ArcView gives no help in alignment), select Layout - Properties from the main menu. Note that the grid will not appear in your output. Set the grid to 0.5 x 0.5 cm, leave the Snap to Grid option on (cheked) then click OK. You should have noticed the dots on the layout grid become closer together.

All map components in a layout are displayed in a frame. The view frame is simply a container that holds a representation of a specific view in your project. You can place any number of view frames onto a layout, and you can move and resize these frames to create the look you want. You will be creating a layout with one view frame and its associated map components (title, scale, north arrow and legend). All map components can be accessed by clicking and holding the left mouse button on the Frame Tool in the tool bar. This will cause a dropdown palette (seen to the right) to be displayed, from which you can choose which component to add by selecting it and releasing the mouse button.
Fig ii. Frame tools dropdown palette


Note that at the bottom of the ArcView window there is a short description of what each tool does. As you move the mouse over each tool the description is updated.

Adding the Map View
While the layout window is active, click on the Frame button and hold down the left mouse button to display the drop down menu bar. Drag the cursor (still holding down the mouse button) down one position to the View Frame tool and release the mouse button. Define the extent (size) of the map on the layout page by clicking, holding and dragging the mouse in the layout window.

When you release the mouse button the View Frame Properties window comes up. In this window, select the view you wish to display in the frame, which in this case is The World. The map view that appears on the layout page is linked to the one that is showing in the chosen view. Changes you make in the view will be reflected automatically in the layout frame map view. BEFORE clicking the OK button you should be aware of how the other options control how the view appears in your layout. These are explained below:

Live Link: Having this box checked means that changes you make to the view are immediatly reflected in the layout. By turning this option off (uncheck the box) you remove the link and the layout view captures the current view state. Changes you make to the view will no longer be reflected in the layout.
Scale: By default, ArcView scales the contents of the view window automatically; that is, if you change the size of the view frame in the layout, the contents of the view frame will be scaled to fit inside the resized frame. If you want the contents of the view frame to be displayed at the same scale as the view, irrespective of the view frame size, you can choose Preserve View Scale from the Scale drop down list. You can also specify the scale directly by choosing UserSpecified Scale.
Extent: By default, if the contents of the view frame are smaller than the view frame, ArcView will try to fill the view frame with data from the view. This may result in data appearing in the layout that is not currently visible in the current extent of your view. If you don''t want this to happen, set Extent to be Clip to View. Use Clip to View if you want to ensure that only those features currently visible in your view will be displayed in the layout.
Display: By default, ArcView only displays the contents of the view frame in your layout when the layout is active. This saves tim

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