Читать книгу GIS Tutorial for Health - Wilpen L. Gorr - Страница 9
ОглавлениеChapter 2
Visualizing health data
Objectives
• Visualize breast cancer mortality by US county
• Understand the composition of GIS map layers
• Learn how to navigate using zooming, panning, and bookmarks
• Understand the connection between visual map features and tabular data
• Learn how to select subsets of map features for processing
• Learn how to find map features
• Use data sorting and labeling to produce information
Health-care scenario
According to the National Cancer Society, breast cancer remains the most frequently diagnosed cancer in women in the United States. Determining top geographic areas where breast cancer deaths occur may lead health officials to provide better targeted screening or interventions.
Solution approach
You are just starting to use ArcGIS, so this chapter focuses on the basics of understanding and using GIS. To begin, you will work with an existing GIS document that you will open in ArcMap and modify by adding and symbolizing a map layer. Once the map document is in usable form, you will explore the map and associated attribute data using several GIS tools to do the following:
• Zoom, pan, and set spatial bookmarks to get close-up views of the map in selected areas of the United States
• Find and identify features and access feature attribute data to get information
• Select subsets of map layers to work with them and sort records to identify top cancer counties
• Label and annotate to add information to maps
Tutorial 2-1
Manipulating layers in a map document
In the first part of this chapter, you will learn the basics of the ArcMap software package. You will begin by opening an existing map document, and then learn how to add and manipulate map layers.
Start ArcMap and open an existing map document
1 On the taskbar, click Start and then All Programs > ArcGIS > ArcMap 10.2
2 Browse through the Maps folder, select Tutorial2-1.mxd, click Open, and click OK if prompted by a warning on VBA code. This map of US cities and states has two map layers already included, renamed, and symbolized. The first layer is Major US Cities (with population over 100,000). The second layer is Breast Cancer Deaths by State. We downloaded this data from the National Cancer Institute’s Cancer Mortality Maps website, http://www3.cancer.gov/atlasplus. This site provides valuable information about cancer mortality in the United States during the time period 1950 – 2004, based on data obtained from the National Center for Health Statistics (NCHS), the federal government’s principal vital- and health-statistics agency. If you wish to obtain other cancer statistics, visit this site or other websites such as http://www.cancer.gov/, http://seer.cancer.gov/, and http://wonder.cdc.gov/ (See facing page.)
Add a layer
You can add additional map layers to your map for more detailed analysis. For example, the National Cancer Institute collects cancer data by county as well as by state. You can add a layer of data showing the breast cancer mortality rates and the number of deaths per county. This data was saved by the authors as a file geodatabase feature class, which contains polygons for counties and related data on death rates.
1 Click the Add Data button .
2 In the Add Data dialog box, click the Connect To Folder button .
3 In the Connect to Folder dialog box, browse to Computer, click the drive where you installed the GISTHealth data (for example, C:\), and click OK. You only need to browse to the root drive and not go beyond this point. Once this connection is made, you can easily browse to any folder on this computer drive. If your data is stored on an external drive such as a jump drive, you will need to connect to that drive.
4 In the Add Data dialog box, browse to \EsriPress\GISTHealth\Data\NCI.gdb, click the BreCounty layer, and click Add.
ArcMap chooses a random color for the counties layer. You will change the color later.
Change the layer display order
Changing a layer’s display order is important because features may be covered up by other features in your map. ArcMap draws map layers from the bottom up, so if larger features are on top of smaller features, the smaller ones will not display.
1 Click the List By Drawing Order button, and then in the table of contents, press and hold the left mouse button on the Major U.S. Cities layer.
2 Drag the Major U.S. Cities layer to the bottom of the table of contents. Because the cities layer is now drawn first, its points are covered up by the states and counties layers and cannot be seen.
3 Drag the Major U.S. Cities layer back to the top of the table of contents. Because the cities layer is now drawn last, its points can again be seen.
YOUR TURN
Drag the BreCounty layer to the bottom of the list and observe what happens. Then drag it back to the middle of the three layers.
Rename a layer
You will notice that when you initially add a layer, ArcMap uses the name of the feature class as the default name of the layer in the table of contents. You will often want to change the name of the layer to a label that is easier to understand.
1 In the table of contents, right-click the BreCounty layer and select Properties.
2 Click the General tab, and in the Layer Name box, type Breast Cancer Deaths by County and then click OK. The layer name is now changed in the table of contents.
Change the boundary-layer fill color
To better see the counties for the Breast Cancer Deaths by County layer, you will want to change the color properties of both the county and the state layers. First, you will change the counties to a white fill color with a light-gray outline.
1 In the table of contents, click the layer symbol for Breast Cancer Deaths by County. The layer symbol is the rectangle below the layer name in the table of contents.
2 In the resulting Symbol Selector dialog box, click the Fill Color arrow.
3 In the color palette, click the Arctic White tile.
4 Click OK. On the map, the fill color of the layer changes to Arctic white.
Change the layer outline color
1 In the table of contents, click the layer symbol for Breast Cancer Deaths by County.
2 In the Symbol Selector dialog box, click the Outline Color arrow.
3 In the color palette, click the Gray 20% tile.
4 Click OK. On the map, the outline color of the layer changes to light gray.
Change the layer outline width
Because county and state boundaries share some of the same lines, it is useful to display the Breast Cancer Deaths by State layer using a Hollow fill and a dark, thick outline so you can see the county polygons above it.
1 In the table of contents, click the layer symbol for Breast Cancer Deaths by State.
2 In the Symbol Selector dialog box, click Hollow.
3 In the Outline Width box, type 1.25, and click OK. (See facing page.)
4 In the table of contents, drag the Breast Cancer Deaths by State layer so it is just above Breast Cancer Deaths by County. The resulting map is much easier to read. The layer names are self-descriptive, and it is easy to distinguish between the county and state outlines.
Drag a layer from the Catalog window into the table of contents
The Catalog window allows you to explore, maintain, and use GIS data through its many ArcCatalog utility functions. From Catalog, you will drag a map layer into the table of contents as an alternative method to add data.
1 Click Windows > Catalog.
2 In the Catalog window, browse through the Data folder to UnitedStates.gdb.
3 Drag USLakes from UnitedStates.gdb in the Catalog window to the top of the table of contents. If you get a warning about the coordinate system, click yes to “use this coordinate system anyway.” The map layers in the table of contents draw in order from the bottom up, so if you dropped USLakes at the bottom of the table of contents, the states would cover the lake features.
Remove a layer
1 In the table of contents, right-click USLakes and click Remove. This action removes a map layer from the map document, but it does not delete it from its storage location — in this case, the United States geodatabase.
YOUR TURN
From the Catalog window, add USRivers and USInterstates from the United States geodatabase. Practice changing the layer colors and outlines, drag the layers to the top and the bottom of the table of contents, and remove the layers when you are finished.
Use Auto Hide for the Catalog window
Notice that when you opened the Catalog window, it opened in pinned-open mode, which keeps the window open and handy for use but also covers part of your map. The Auto Hide feature of this application window, along with other application windows such as the Table Of Contents and Search windows, keeps the windows available for immediate use but hides them between uses so that you have more room for your map.
1 Click the Auto Hide button at the top of the Catalog window. The window closes but leaves a Catalog button on the right side of the ArcMap window .
2 Click the Catalog button. The Catalog window opens.
Next, you will simulate completing a Catalog task by clicking the map document. The window will automatically hide.
3 Click any place on the map or in the table of contents.
You can pin the window open again, which you will do next.
4 Click the Catalog button and then the Unpinned Auto Hide button . This action pins the Catalog window open until you click the pin again to automatically hide or close the window. Try clicking the map or the table of contents to see the Catalog window remain open.
5 Close the Catalog window.
Use relative paths
When you add a layer to a map, ArcMap stores the path to its location in the map document. When you open a map, ArcMap locates the layer data it needs by using this stored path. If ArcMap cannot find the data for a layer, the layer still appears in the ArcMap table of contents, but of course it does not appear on the map. Instead, ArcMap places a red exclamation mark (!) next to the layer name to indicate that its path needs repair. You can view information about the data source for a layer and repair it by clicking the Source tab in the Layer Properties dialog box.
Paths can be absolute or relative. An example of an absolute path is C:\EsriPress\GISTHealth\Data\UnitedStates.gdb\USLakes. To share map documents saved with absolute paths, everyone who uses the map must have exactly the same paths to map layers on their computer. That is why rather than absolute paths, the relative path option is favored.
Relative paths in a map specify the location of the layers relative to the current location on the disk of the map document (.mxd file). Because relative paths do not contain drive letter names, the map and its associated data can point to the same directory structure, regardless of the drive or folder in which the map resides. If a project is moved to a new drive, ArcMap will still be able to find the maps and their data by traversing the relative paths.
1 On the Menu bar, click File > Map Document Properties. Notice that the check box is selected to “Store relative pathnames to data sources.” This option should be set for all map documents in the tutorials and the end-of-chapter assignments in this book.
2 Click OK.
YOUR TURN
Explore the other options in the Map Document Properties dialog box. Type a brief description and enter your name as the map author. When you are finished, click OK.
Save the map document
1 On the Menu bar, click File > Save As.
2 Save your map document as Tutorial2-1YourName.mxd to your Chapter2 folder in MyExercises. If you get a VBA code warning, click OK. Do not close ArcMap.
Tutorial 2-2
Zooming to and panning health features on a map
Sometimes you will want to concentrate on a particular area of a map. You will also quickly learn that some geographic features are too small to see when viewing an entire map. If you enlarge a particular area, you can see the details more easily. Zooming and panning enlarges or reduces the display and shifts it to reveal different areas of the map. You will find zoom and pan buttons on the Tools toolbar.
Zoom in
1 On the Tools toolbar, click the Zoom In button .
2 Press and hold the mouse button on a point above and to the left of the state of Illinois.
3 Using the mouse, drag the pointer to draw a box around the state of Illinois. Then release the mouse button.
The resulting map is a zoomed area of the state of Illinois.
4 Click the screen to zoom in, centered on the point you clicked. This is an alternative to drawing a rectangle for zooming in.
Pan
If you want to see a neighboring state without zooming out, use the Pan button.
1 On the Tools toolbar, click the Pan button .
2 Move the pointer anywhere into the map view.
3 Pressing the left mouse button, drag the pointer in any direction.
4 Release the mouse button. Panning shifts the current map display to the left or right, up or down, without changing the current scale. In the figure, you can see Illinois, Indiana, and Ohio. (See facing page.)
Zoom to the full extent
If you want to zoom out to view the entire map, use the Full Extent button.
1 On the Tools toolbar, click the Full Extent button . The map zooms out to the outermost extent of all features.
YOUR TURN
Practice using the other zoom functions such as Fixed Zoom In and Fixed Zoom Out, which zoom by a fixed percentage at each click. You can zoom back to the previous extent by using the blue arrow on the Tools toolbar. Zoom to the full extent of the map when you are finished.
Save the map document
1 On the Menu bar, click File > Save As.
2 Save your map document as Tutorial2-2YourName.mxd to your Chapter2 folder in MyExercises. Do not close ArcMap.
Tutorial 2-3
Creating spatial bookmarks
Spatial bookmarks save the current display, at its current zoom status, with a name. You can then easily return to the saved area by accessing the bookmark. This is useful if you use GIS in presentations or if you want to move quickly to a study area or region of interest.
Create a bookmark
1 With the Zoom In button selected, drag the pointer to draw a rectangle around Florida to zoom to the state of Florida. This will zoom in to the extent of the state of Florida.
2 On the Menu bar, click Bookmarks > Create Bookmark, type Florida for Bookmark Name, and click OK.
3 On the Tools toolbar, click Full Extent.
4 On the Menu bar, click Bookmarks > Florida. ArcMap zooms to the extent of the saved bookmark for Florida, which can be helpful if you frequently zoom to this extent.
YOUR TURN
Zoom to and create spatial bookmarks for California, New York, and Texas or other states that may be familiar to you. Try out your new bookmarks. On the Bookmarks menu, click Manage Bookmarks and remove the California bookmark. Zoom to the full extent when you are finished.
Save the map document
1 On the Menu bar, click File > Save As.
2 Save your map document as Tutorial2-3YourName.mxd to your Chapter2 folder in MyExercises. Do not close ArcMap.
Tutorial 2-4
Identifying breast cancer mortality rates and deaths by state
Using GIS, you can interact with map layers to get information. The Identify tool is a commonly used point-and-click tool for browsing through attribute data associated with a map feature. In this section, you will use the Identify tool to learn about mortality rates and the number of breast cancer deaths per state and per county.
Identify features
1 Turn off all layers except Breast Cancer Deaths by State.
2 On the Tools toolbar, click the Identify button .
3 Click inside the state of Texas.
The state of Texas temporarily flashes and the results appear in the resulting Identify dialog box. The names of attributes use the following codes: R = Mortality rate per 100,000 people, C = Number of deaths, WM = White Male, WF = White Female, BM = Black Male, and BF = Black Female. Date ranges are also shown: 95_99 = 1995 – 1999 and 00_04 = 2000 – 2004. So, if you are interested in the mortality rate for white females from 2000 to 2004, you would look for the field RWF00_04. You can see that this mortality rate is 23.579. The rate for all ages by state per 100,000 persons is age-adjusted using the US population in 2000.
4 Click another state to see the breast cancer mortality rates for white females from 2000 to 2004.
5 Close the Identify dialog box.
Restrict layers to identify
If you have many layers turned on, you may have difficulty selecting the appropriate feature to identify. For example, if both layers are turned on, you may select a county instead of a state. To solve this problem, you can restrict the identify selection to one layer only, ignoring the features in other layers.
1 In the table of contents, click the Breast Cancer Deaths by County layer to turn it on.
2 On the Tools toolbar, click the Identify button.
3 Click any state or county polygon feature.
4 In the Identify dialog box, click the “Identify from” arrow and select Breast Cancer Deaths by County. This restricts the identify selection to features in this layer only, ignoring the features in other layers.
5 Zoom to the state of Texas. Use your spatial bookmark if you created one.
6 Click any county polygon feature in Texas. Observe the attribute values in the Identify dialog box. Notice that another date range (1990 – 1994) for breast cancer counts and rates is available for counties.
7 Close the Identify dialog box.
YOUR TURN
Practice using the Identify tool in a geographic area that interests you. Restrict the layers to state, county, and major US cities, and observe the data in each feature class. Are you able to observe any health-care trends for breast cancer?
Use advanced Identify tool capabilities
You can use the Identify tool to navigate and create spatial bookmarks.
1 Zoom to the full extent and turn off all layers except Breast Cancer Deaths by State.
2 Click the Identify button, click inside any feature, and in the “Identify from” list, click Breast Cancer Deaths by State.
3 Click inside the state of Illinois.
4 In the Identify dialog box, right-click the state abbreviation name (IL) and click Zoom To. The map display zooms to the extent of the state of Illinois.
5 Right-click the state abbreviation name again and click Create Bookmark.
6 Close the Identify dialog box.
7 Click Full Extent.
8 Click Bookmarks > IL.
Save the map document
1 On the Menu bar, click File > Save As.
2 Save your map document as Tutorial2-4YourName.mxd to your Chapter2 folder in MyExercises. Do not close ArcMap.
Tutorial 2-5
Selecting map features
GIS links graphic features of a map layer to associated attribute records in a table. When you select features on a map, you can correlate them with the records in the table. That way, you can perform functions on a subset of features and records, including generating statistics, making new layers, or doing analysis.
Select a single feature
1 In the table of contents, turn on the Major U.S. Cities layer.
2 Click Full Extent.
3 On the Tools toolbar, click the Select Features button .
4 Click inside Texas. The selected state feature is highlighted on the map.
Select multiple features
1 To make multiple selections, hold the SHIFT key and click inside each of the states surrounding Texas.
Change the selection color and clear a selection
Sometimes you will want to produce a map that has certain features selected. Then you’ll want to be able to change the selection color for the purpose at hand. For example, a bright red color might be better for drawing attention to map features.
1 On the Menu bar, click Selection > Selection Options.
2 In the Selection Options dialog box, click the color box under Selection Tools Settings.
3 Select Mars Red as the new selection color and click OK.
The selection color for map features is now bright red.
4 On the Selection menu, click Selection > Clear Selected Features.
Set selectable layers
When there are many layers in a map document, you may want to restrict which ones are selectable. This simplifies the selection process.
1 In the table of contents, turn on all three map layers.
2 At the top of the table of contents, click the List By Selection button .
3 Click to clear the check boxes for Breast Cancer Deaths by State and Breast Cancer Deaths by County to make only Major U.S. Cities selectable. Now only cities will be selected.
4 Click the Select Features button and click a city. The selected city gets the selection color you chose previously and is listed in the table of contents. The name of the city is also displayed in the table of contents.
5 On the Tools toolbar, click the Clear Selected Features button .
Select features by graphic
Selecting features by using graphics is a faster way to select multiple features.
1 Click Bookmarks > Florida.
2 Click the Select Features arrow and then Select by Circle.
3 Click inside the state of Florida and drag the pointer to draw a circle that includes five cities in the central and northern parts of Florida. The resulting map shows multiple cities selected and the resulting names included in the table of contents.
Zoom to selected features
1 Click Selection > Zoom To Selected Features. ArcMap zooms to the features selected.
Change the selection symbol
In addition to changing the color of selected features, you can change the symbol either for the entire map or for individual layers.
1 In the table of contents, right-click the Major U.S. Cities layer and click Properties.
2 Click the Selection tab and click the Symbol button.
3 Click Square 1, Dark Amethyst, and size 12 as the new selection symbol and click OK twice.
4 The cities will be displayed with the new selection symbol.
5 Clear the selected features and zoom to full map extent.
YOUR TURN
Zoom to Texas. Click the Select Features arrow and click Select by Lasso. Select multiple cities in the state of Texas. Clear the selected features.
In the table of contents, make Breast Cancer Deaths by County the only selectable layer. Select features for five counties in Texas, zoom to those selected features, and then clear the selection.
Save the map document
1 On the Menu bar, click File > Save As.
2 Save your map document as Tutorial2-5YourName.mxd to your Chapter2 folder in MyExercises. Do not close ArcMap.
Tutorial 2-6
Finding map features
The connection between GIS features and their attributes provides several ways to locate features in the map. In cases where you know what you’re looking for but don’t know its location, you can use the Find tool.
Use the Find tool
1 Zoom to full map extent and make all map layers selectable.
2 On the Tools toolbar, click the Find button .
3 In the Find dialog box, in the Find box, type Philadelphia; for In, select <All layers>; and for Search, select the “Find features that are similar to or contain the search string” check box.
4 Click Find. The results appear in the bottom section of the Find dialog box. Note that ArcMap finds both the city and the county of Philadelphia. Both these records were located because the software searches all visible layers. You can restrict the Find tool to a specific layer by using the In list seen in step 3.
5 Right-click the city name and click Zoom To.
The resulting map zooms to the city of Philadelphia.
6 Close the Find dialog box.
Save the map document
1 On the Menu bar, click File > Save As.
2 Save your map document as Tutorial2-6YourName.mxd to your Chapter2 folder in MyExercises. Do not close ArcMap.
Tutorial 2-7
Using an attribute table to select counties with high breast cancer rates
Each map layer has an associated feature attribute table that contains the data associated with every feature in the layer. Open the attribute table to explore the attributes for the layer on a map. The attribute table provides information you can use to query the data. In this section, you will use attribute tables to determine which US counties had the highest counts and rates of female breast cancer deaths.
Show the connection between layers and tables
1 Zoom to full map extent.
2 In the table of contents, click the List By Drawing Order button.
3 Right-click the Breast Cancer Deaths by County layer and click Open Attribute Table. The table, which contains one record for each county feature, appears. Each layer has this table, which contains one record per geographic feature.
4 Resize or move the Breast Cancer Deaths by County attribute table so that both the map and the table can be viewed simultaneously on the screen.
5 Click the record selector (gray box) at the far left of the table for the first county (Autauga, Alabama) to select that record. Notice that the county is also highlighted on the map.
6 Scroll to the right in the attribute table to see the breast cancer rates and counts for this county.
YOUR TURN
Click the record selector for various counties in the attribute table to highlight them on the map. Click various counties on the map to highlight them in the feature attribute table. Find the county where you live or one that is familiar to you. Select your county in the attribute table and see the county highlighted on the map. Clear your selected features when you are finished.
Dock the attribute table
In ArcGIS, you can move a window to a new location and dock it or make it stationary. When you move the attribute table window, blue targets appear representing the different locations where you can dock the window. You can drag the window to the target of your choice and drop it there to secure it.
1 Drag the attribute window by its title bar to a new location. You will see blue target arrows indicating where you can “drop” the attribute window. Pause over a target to get a preview of where the window will be located if you drop it on that target.
2 Drop the window on the target at the bottom of the screen. The attribute table appears at the bottom of the window, and the table of contents and the map are at the top of the screen.
YOUR TURN
Practice moving the attribute table to various locations on the screen. When you are finished, leave the table floating in the map document.
Move a field
Next you will move and sort fields in the feature attribute table. In particular, you will sort fields in descending order by the total deaths in each county, and then select the highest number of deaths for the entire United States or for a selected state.
1 On the Tools toolbar, click Clear Selected Features.
2 In the Breast Cancer Deaths by County table, click the column heading (known as the field name) of the STATE_NAME field, and then press and drag it to the left of the NAME2_ (county name) field.
3 Move the CWFBF00_04, RWF00_04, and RBF00_04 fields until they are to the immediate right of NAME2_. Notice that the field CWFBF00_04 combines both white and black females. In chapter 5, you will learn how to combine multiple fields using a field calculator.
Sort a single field
1 In the Breast Cancer Deaths by County attribute table, right-click the CWFBF00_04 field name and click Sort Descending. This sorts the table from the largest number to the smallest number of breast cancer deaths for all females in each US county from 2000 to 2004.
Select the counties with the highest counts of breast cancer
Now that you have prepared the attribute table to sort by the highest number of breast cancer deaths, you can select records to isolate top cancer counties on the map.
1 In the Breast Cancer Deaths by County table, press CTRL and click the row selectors for the first five records in descending order. Notice that the corresponding features are highlighted on the map. The areas selected as having the highest number of breast cancer deaths might not be surprising because these are some of the most populated counties in the country.
Select the counties with the highest breast cancer rates
A better indicator of breast cancer is the mortality rate per county.
1 In the Breast Cancer Deaths by County attribute table, right-click the RWF00_04 field name and click Sort Descending.
2 Press CTRL and click the row selectors for the first five records in descending order. Notice that the corresponding features highlighted on the map for the rate of breast cancer deaths for white females are much different from those for the highest count of breast cancer deaths for white females. (See facing page.)
YOUR TURN
Find the counties that had the highest rates of breast cancer deaths from 2000 to 2004 for black females. Clear your selections when you are finished.
Sort multiple fields
Sorting by the number of cancer deaths was useful for finding the counties that had the highest number of breast cancer deaths and death rates across the United States, but what if you wanted to examine the number of deaths for one state? To do this, you would need to sort the records by two fields: state and number of deaths.
1 Right-click the STATE_NAME field and click Advanced Sorting.
2 In the Advanced Table Sorting dialog box, click the “Sort by” arrow, select STATE_NAME, and select the Ascending option if it is not already selected. This sets up the first sort order to sort alphabetically by state.
3 In the Advanced Table Sorting dialog box, click the “Then sort by” arrow, select CWFBF00_04, and select the Descending option. Click OK. This sets up the second sort order to sort for highest-to-lowest female deaths between 2000 and 2004.
4 Scroll through the list until you find the records for Texas.
5 Select the first five records for Texas. This selects the five counties that had the highest number of breast cancer deaths for all females.
6 Close the attribute table.
7 Click Bookmarks > Texas or zoom to Texas. The resulting map shows the locations of the five counties that had the highest number of female breast cancer deaths in Texas. (See facing page.)
Show only selected records
1 Open the Breast Cancer Deaths by County attribute table and click the “Show selected records” button . This shows the records for only the features selected in the map.
2 Click the “Show all records” button to show all records again.
3 Close the attribute table.
Save the map document
1 On the Menu bar, click File > Save As.
2 Save your map document as Tutorial2-7YourName.mxd to your Chapter2 folder in MyExercises. Do not close ArcMap.
Tutorial 2-8
Creating a new layer of a subset of features
Sometimes just a subset of features is needed in a map layer. For example, in this tutorial, you will create a layer that has the counties you just selected.
1 Right-click the Breast Cancer Deaths by County layer and click Selection > Create Layer From Selected Features. This adds a new layer to the table of contents that contains just the five counties in Texas that had the highest number of breast cancer deaths.
2 Rename the new layer Top 5 Texas Counties, Female Breast Cancer Deaths 2000-2004 and change the color fill to Mars Red.
3 Drag the new layer below Major U.S. Cities and clear the selected features. The resulting map clearly shows the Texas counties that had the highest number of female breast cancer deaths between 2000 and 2004.
Save the map document
1 On the Menu bar, click File > Save As.
2 Save your map document as Tutorial2-8YourName.mxd to your Chapter2 folder in MyExercises. Do not close ArcMap.
Tutorial 2-9
Creating a point map based on a definition query
Sometimes just a subset of features is needed in a map layer. Suppose you have a layer that contains all the cities in the United States, but you want to display only the cities in Texas that have a population over 600,000. To do this, you can create a definition query to filter out all the cities that have population values outside the desired range but keep those that are in Texas in the desired range.
