In this exercise, we will use coverages of Cambridge roads and U.S. Census block group data to explore the basic mapping capabilities of ArcGIS.

Click here for today's in-class notes.

I. Setting Up a Work Environment

A. Start an ArcGIS Session

First, we need to Log onto a PC that can run ArcGIS and access the class data lockers. We will use a WinAthena PC such as those in MIT Room 10-485, and the 5th floor of building 9 (i.e., various CRON-supported computing facilities). The user name and password for logging in are the same as our MIT (Athena) email IDs and passwords.

Step 1. Find the lab exercise instruction on the class website.

Launch any web browser on your PC's desktop (either Mozilla Firefox or Internet Explorer will do), open the class website, http://mit.edu/11.188, and navigate to the page you are reading now: http://web.mit.edu/11.188/www/labs/lab1. Keep this exercise open in a web browser while you work. You may print a copy of this exercise if you wish, but we recommend working directly from a browser window since the monitor is large and high resolution enough to display both the browser window and ArcMap window at the same time. In addition, we will use some in-class notes during our presentation of key ideas of Lab #1. These notes are available here: lab1_inclass_notes.txt

Step 2. Check out the 11.188 class Locker

Much of our class data reside in the course locker, 11.188. This locker is accessible online via the Andrew File System (AFS) at /afs/athena.mit.edu/course/11/11.188 (using the forward slash '/' unix notation). From campus PCs running openAFS software, you will find the same class locker at Z:\course\11\11.188. (Note: On most WinAthena machines, the Z:\ drive is mapped to 'athena.mit.edu' which is the top of the MIT portion of the worldwide AFS tree. If you load openAFS on a personal PC, drive Z will be mapped to the top of the AFS tree: \afs and 'athena.mit.edu' will be one level down from the top. [Note: ArcMAP can have trouble trying to read upper-level directories on AFS drives. ArcMAP insists on trying to find mapable data in each sub-directory that it examines. The upper-level directories on AFS are spread among machines around the world and ArcMAP will spend forever looking. You can avoid this problem by only building folder connections in ArcCatalog that connect to Andrew File System lockers on the MIT network.)

Since we will use the class locker repeatedly, we might as well map the locker to a 'virtual' local drive and avoid this problem. You can use the Tool/Map-network-drive option from a Windows Explorer window to map the class locker. We suggest that you map the class locker using this name "\\afs\athena.mit.edu\course\11\11.188\" to your M:\ drive. Another way to map the class locker to a local drive is to run this command in a DOS command window: "net use M: \\afs\athena.mit.edu\course\11\11.188". This command has been saved as a batch command file named "attach_m.bat" at the top level of the class locker. You can navigate in a Windows Explorer window to Z:\course\11\11.188 and then double-click on attach_m.bat to mount the drive. You may also copy this batch file into a convenient location in your personal locker (on Drive I:) and double-click on it when you want to mount the class locker.

Step 3. Start ArcMap (the primary interactive mapping application within the ArcGIS suite of applications):

On any WinAthena machine, ArcMap can be started via Start/Programs/ArcGIS/ArcMap. However, running ArcGIS on CRON or WinAthena machines around campus can be painfully slow unless you take steps to insure that default files and datasets are *not* located on your network locker space. In general, we recommend that you copy all data, saved documents, and workspaces to a local hard drive before beginning lab exercises. Dr. Rob Goodspeed (a former DUSP PhD student and current professor at UMich) wrote a useful set of notes (for 11.205/11.520 during Fall 2013) that explains how to setup your workstation to improve ArcGIS's performance. This document is in our class locker: 11.520_Setup_Guide.pdf

Please wait patiently for ArcMap to launch. The program takes awhile to come up. Notice that in the program group of ArcGIS, there is another entry called ArcCatalog, which we will use soon.

B. ArcMap Document Setup

When ArcMap first launches, you should see an "ArcMap" window, illustrated in Fig. 1, that prompts you to create or open a new map. Click the radio button next to A new empty map and then 'OK' to make this window go away.

Fig. 1. ArcMap's Starting Window

You should now be looking at an "empty" document which has "Untitled" in the title bar and looks like the image in Fig. 2.

Fig. 2. The Untitled map document

This is approximately what ArcMap might look like. All of the controls are dockable, customizable, and saved when you exit ArcMap so the appearance can vary from one user to the next or from one session to the next. The 'dockable' behavior means the tool bars can also be 'free floating'. For example, the tools panel, which has the pan and zoom tools, can be anchored to the top bar of the window or, if you wish, pulled free as a separate tool bar window that can be moved anywhere on your screen. I keep this tools panel docked on the upper left side of ArcMap since I use it most often and want to be sure it is handy. My version is what I have modified slightly from the base that you will see when you start ArcMAP.

What's on the interface, besides the pan and zoom tools? Some drawing tools (see the bottom of the window), some menus which give you access to customizing tools among other things, and some map management tools. We will use many of these in this course.

II. Visualizing Your Data

A. Getting Data Into ArcMap

We are now ready to begin looking at data sets. You will spend most of your time in this map document window, experimenting with good ways to symbolize a data set and overlaying various spatial data sets to create a map. Typical spatial data sets include ArcInfo coverages and ArcMap shapefiles.

When a data set is brought into a map document, we will call it a layer. We need a new term because the same data set can be used to build many different layers, depending on the symbology used and other variables.

We can add data sets to this map by clicking on the "Add Data" button in the toolbar and navigating our file system to find coverages, shapefiles, or other datasets that ArcMap knows how to interpret. Try this now. The 'Add Data' window is shown below but the entries will be different in your window depending upon lockers you may have visited previously. We'll start by locating a data set of the Cambridge city boundary, which is stored at M:\data. [Note that, at this point, we assume you have already mapped the class locker to Drive M:. You can access the same datasets by navigating to "Z:\course\11\11.188\data". Either way will work but, if you save your work in an ArcMap document and then open the document later, perhaps in another lab, the document with look for the dataset in the original location,]

Fig. 3. Add Data

Your 'Add Data' dialog box may show different possible locations (compared with the above diagram) depending upon where you have last looked for data. The 'Add Data' dialog box shows the same folder locations as are shown if you expand the 'Catalog' tab shown as a vertical tab on the right side of Fig. 2 above. Local drives such as C and D are already registered with Catalog by default. You need to connect to other folders manually. Click the "Connect to Folder" Button .

In the "Connect to Folder" window, choose [M:\] then [data] from directory tree (or get there via: Z:\course\11\11.188\data). It contains all data sets needed for this lab.

Fig. 4. Connect data folder

Click OK and go back to the "add data" window. Now you are in the right directory, you should be able to see a number of data sets in the window. Select the 'camborder polygon' data set, which contains the border of the city of Cambridge, and then Add it. [Note that you have added a 'shapefile' version of the Cambridge border dataset. An alternative, coverage, version of Cambridge border is available in the 'old_data' subdirectory. The format of an ArcGIS 'coverage' dataset includes more topology information and stores all the geometry in a folder with the coverage name and all data tables in a separate folder called 'info'.]

Now, let's add another dataset, the cambridge tiger file. We suggest that, this time, you find the dataset using the ArcCatalog tab (with this icon: ) on right side of the ArcMap window. Find the cambtigr shapefile that is also in the 'data' folder of the class locker and contains linear feature - street centerlines - for all the roads in Cambridge.. To add this dataset to ArcMap, you can grab it by left-clicking and holding the mouse over the 'cambtigr' name and dragging-and-dropping it into your ArcMap window.

Fig. 5. Adding Cambridge border coverage via drive Z:

Fig. 6. Add data from ArcCatalog

Now add the following two layers to your ArcMap, with either of the two above methods. (Since you have already registered the M and/or Z drives, you don't need to register them again).

• cambbgrp.shp (The U.S. Census 1990 block groups in Cambridge)
• sales89.shp (Cambridge housing sales in 1989)

You should be able to get a map window looking like the following figure.

Fig. 7. ArcMap window with GIS layers

All four layers that you have added are currently visible. To activate a layer or deactivate it, just click on the box next to that layer's title. If the box is checked it means that the layer is visible. Initially, all the checkboxes are checked, and all data will be visible in the data display area. Experiment with turning layers on and off.

Notice that some layers may obscure others. That's because the themes are drawn from bottom to top as listed in the data frame area. You can change the drawing order of the layers by clicking and dragging a layer in the data frame area. Try this now to see how the display changes while you arrange the layers in different ways. But finally, they should appear in the following order: (Note that, for the rearrangement of layer order to work, the Table of Contents window needs to be listed by 'drawing order'. Make sure the left-most icon under the 'Table of Contents' label is clicked so the window lists the contents by drawing order.)

• Sales89
• Cambtigr
• Cambbgrp
• Camborder

Your window should now resemble the above figure. Note that since ArcMap chooses the initial colors for themes randomly, your window will probably have different colors than those shown here. Also, the name of the layers may also be a bit different, depends on whether you use a coverage or a shape file.

At this point it is important to set a few properties for this document file. Select Data Frame Properties under the View menu. The "data frame properties" window will show up. Click "general". The window looks like the following figure.

Fig. 8. Data Frame Property Window

Now change the name of the view from layers to Lab Exercise 1. Also notice that in this dialog box the map units are set to meters, in which the spatial coordinates of the data are actually stored in the files on the disk. The display units, in contrast, refer only to how distances will be measured for display. We can set this to any units we like; we suggest feet here because that is a familiar unit (for Americans), is appropriate to the scale of the map, and illustrates the fact that the display units can be different from the map units of the X/Y locations that are stored with the coverage or shapefile.

Now take a few minutes to familiarize yourself with some toolbar buttons. You can pan and zoom in the view window. First, you may wish to enlarge both the ArcMap window and the data display area so that you can see more detail in the image. Also try these buttons out by clicking on them in the toolbar, then clicking in the data display area:

Zoom In		Click to zoom in on that location. Click and drag to zoom to a particular bounding box.
Zoom Out		Click to zoom out centered on the location of the click.
Pan		Click and drag to pan around the map area.

Discover functions of the other buttons on the toolbar on your own. Notice that as you move your mouse cursor over the button, a line of descriptive text will appear, which explains the function of the button.

B. Examining Attribute Data

Click on the small boxes next to the each layer to make them invisible. Then turn on the layer Cambbgrp in the data frame. Now you can see the outlines of Cambridge Census block groups.

Click once on the info ("i") tool. This button is located in the toolbar. Move the mouse into the map window and click on a block group. The attributes associated with that block group appear in a popup window. To see the data for all of the block groups, move your mouse over the name of the layer in the data frame and do a right click. On the pop-up menu, choose "open attribute table". Notice that if you click on a record in the table, the corresponding block group is highlighted on the map. Likewise, you can select regions of the map and the corresponding rows in the attribute table will be highlighted. To see this effect, click on the feature selection tool in the tool bars, and then left-click and drag the mouse cursor to highlight a square box across some portion of the Cambridge map. All the Cambridge block groups that have any part within the selection window will be highlighted along with their corresponding attribute rows. click on the blank map area. [Note: Since we have more than one dataset 'theme' included in our map, we may want to control which themes are selected using the selection tool. Controlling the selection behavior is one of many customizable elements of ArcMap. One of the icons under the label of the 'Table of Contents' window helps you control selections. Mouse over the icons to see which one it is.]

Now we can save the map document to our working directory. Do this by clicking the save button . Go to your Athena locker, which is your I: drive. We suggest you create a sub-directory called 11.188 within your I:\Private directory. Within this directory, you should create another folder called lab1. Now you can save your map document file to this directory. Give this document file whatever name you like. It does not save all the data you are using - only the file locations, date frame properties, symbol information and the like that are needed for ArcMAP to recreate the same state of your work that existed when you saved the file. (Hence, the saved document file - with an .mxd filename extension - will not work properly if the class locker is not mapped to the same drive as it was when you saved the file.)

III. Basic Map Making

A. Simple Symbolization

Click on the check box next to the Cambtigr layer to make it visible. You should see all Cambridge roads (plus some other features such as railroads) being drawn on the map. If you had moved, say, Cambgrp above Cambtigr in the legend, the TIGER(Topologically Integrated Geographic Encoding and Referencing system) arcs would then be quickly covered up by the block groups. If so, you can fix this by dragging the Cambtigr layer up above the Cambbgrp layer. Now we see TIGER arcs on top of the block groups.

The name Cambtigr may not be meaningful to everyone viewing this display. We can easily rename the layer in the property window to something more readable. Right click once on the word Cambtigr and select Properties from the pop up menu. Under "General", change the layer name from Cambtigr to Cambridge TIGER. Notice that the data source (listed in the legend when the "Source" tab at the bottom of the DataFrames 'legend' window is selected) does not change. After you click the OK button, you will see the new layer name in the data frame. You may need to make the data frame window wider to see all the text. Move the mouse over the line to the right of the data frame area. When the cursor changes to an I-beam with arrows on either side, you can click and drag to resize the data frame area.

Fig. 9. Symbol Selector Window

For now, the layer Camborder is actually not visible even when the box is checked. To make it visible we can drag it above the Cambridge TIGER layer. (Note that reordering the layers in this manner only works when the "display" and not the "source" tab is active.) However, when Camborder is on top, it obscures the roads. Instead of moving Camborder to the bottom again, we can change the way it is displayed so that the border is drawn but the area is not filled in. Double-click on the legend, which is the rectangle under the layer name Camborder in the Symbol Selector window as shown by Fig. 10, Click once on the downward arrow of the "Fill Color" option, which is at the middle right. And then choose "No Color". This sets the fill color for the shape to be "none" (i.e., transparent). The fill pattern had been the colored box, meaning that shapes were filled with a solid color.

Also, increase the outline width from 0.40 to 2. Click "OK". Now you are able to see, at the same time, the boundary of the city and the block group boundaries.

Likewise, you can improve the way to visualize the tiger lines. Try that by yourself.

B. Thematic Symbolization: Your first thematic map

Double-click on Cambbgrp to open the layer property window. This time we will manually symbolize the theme. Up to now, all the layers have used the default legend type, "Single Symbol." Now, under "Symbology:" select "Quantities" and then "Graduated Color." Change the classification field value to "Med_hh_inc." Notice that ArcMap automatically divides the income data into five ranges and assigns a color to each. These colors will not actually be shown in the map until we explicitly tell ArcMap to do so.

At this point, we should clear any selected features so none of them are highlighted. There are several ways to do this. One is to use the feature selection tool to click on the blank map area. Another way is to use the Selection/Clear-Selected-Features menu choice.

Often we will want to make some adjustments to the way these ranges are created. To do so, click on the Classify button. The Classification window will appear. Under "Classification Method:" select "Quantile" and note breakpoints are adjusted for the histogram along the bottom of the classification window. Click OK to close this window.

Back in the symbology window notice that the ranges have changed to reflect the new classification scheme. Now click Apply to make this new scheme take effect in the map. You've made your first thematic map, with median household income divided into 5 categories, each consisting of 20% of the block groups.

Notice that the first income range is 0 - 23472. On the surface, this may seem fine, but actually in this data set, the value zero is used to indicate that there is no data for that block group, not that the median income is zero (which is extremely unlikely). You can confirm that the zero value is an outlier by taking a quick look at the raw data. Close the property window and bring forward the attribute table of Cambbrp. Right click the layer's name in the data frame and select Open Attribute Table on the pop-up menu.

Scroll to the right in this window until you see the Med_hh_inc column. Right click on the column heading for Med_hh_inc; it will be highlighted when you do so. Now sort the rows in ascending order using the Sort Ascending option. You should end up with a window that resembles Fig. 12. Notice that there are three block groups with zero values, and the next higher value is 13009.

Fig. 12. Sorted Attributes of Cambbgrp

We can prevent such situations from distorting our maps by specifying a "null value" in the classification. Go back to the classification window (Layer Properties> Symbology> Classify) and click on the Exclusion button. The Data Exclusion Properties window will appear.

Specify the query to match what is shown in Fig. 13. And then go to the Legend Tab. Type in "Null Value" in the label field. Make sure the check box for Show Symbol for Excluded Data is checked. Click OK. to close the window. Notice that all but the last of the ranges changed; in particular, the first range is now 13009 - 25335.

Fig. 13. Exclude Non Value Records

Now we can experiment with different classification methods. Try going back to the symbology window, then click the "classify" button and classify Med_hh_inc by "Standard Deviation" instead of "Quantile." The mean should match the mean generated under statistics. In fact, once you become a proficient map maker, you might not use these preset classification schemes at all. You could type your own ranges into the "Value" field of the Legend Editor, basing your ranges on standard deviation, variance, quartiles, quintiles, or any other defensible scheme you devise.

What are these different classification methods about? Now is good time to use the ArcGIS online help system to get some more information. Select ArcGIS desktop help from the Help menu. (The same Help system is directly available from the windows Start/Program/ArcGIS menu.) The help system may take some time to load. In the ArcGIS Desktop Help window, click on the "Index" tab. In the keyword box, type the first few letters of the word you're looking for, i.e. classification. You will find "classification schemes" in the returned query list. Click "display", then select "Standard classification scheme" in the pop up window, explanation for the classification method will show up in the right area.

More thematic mapping

Now let's go back to the ArcMap window. Right click once on the Cambbgrp layer and select Copy from the pop up menu. Right click on the data frame name Lab Exercise 1, select Paste Layer from the pop up menu. Now you will have two identical Cambbgrp layers in your data view. Rename the new layer from Cambbgrp to Households. You can do this as by bringing up the layer property window, as indicated in the previous section. However, you can also do it by clicking the layer name twice, as you change a file name in a windows explorer. (notice that it is not a double-click.)

Now let's make a basic thematic map showing the number of households per block group. Double-click on the new layer named Households to load the symbology window. Under "Symbology" select "Graduated Color". Change the classification field from Med_hh_inc to Households. Click on the Classify button to open the Classification window. Use these options:

Type: Quantile
Number of classes: 5

Right click once on the Households layer and select Copy from the pop up menu. Right click on the data frame name lab exercise 1 and Select Paste layer from the pop up menu. Now we have three versions of the block groups visible in the legend. Change the name of the newest one from Households to Household Density. Double-click on the new layer to load its property window. Change the normalization field from NONE to Landacre. Remember to go to the classification window and change the classification method to Quantile. The default one is Natural Breaks.

Instead of showing raw counts of households per block group, the Household Density layer shows households per acre in each block group. The density layer normalizes the raw counts by dividing them by the land area. Note that a density map is more meaningful than a map of block-group counts since the counts are so sensitive to where you draw the block group boundaries. If some block groups were divided in two, the thematic map of counts in each block group would change a lot, but the density wouldn't change. Use the check boxes to toggle the visibility of the layers. Notice how different the two maps look and understand that household density is quite different from total households. Also understand what the normalize command did. It took the number of households in the block group and divided it by the number of acres in the block group. Normalization of data is an important issue that we will return to during the semester.

Make a new copy of the household density layer and change its name to Household Density SD. Load its symbology window with a double-click on the layer name. Make sure your classification field is "Households" and that you are normalizing by "Landacre." Click on the "Classify..." button and choose "Standard Deviation" (accept the defaults for the other fields). Apply your changes. This map helps us see how much density differs across the city. We see mainly light colors (within +/- 1.5 standard deviation from the mean), leading us to believe that Cambridge households are relatively evenly spread around the city. This makes sense because there are no (or few) 40-story high density apartment buildings, few areas with single-family homes on large lots, and few completely nonresidential districts.

Mapping point data

So far we've only looked at polygon data. Mapping point data offers new challenges and opportunities. Make the layer sales89 visible. We see that property sales were pretty evenly spread across the city in 1989 (except in a few block groups, most notably around MIT). Simply looking at where sales isn't very interesting in this case.

Load the symbology window with a double-click. Choose the "Graduated Symbol" legend type and classify on "Realprice" and classify by "Quantile." Apply your changes. This gives us an idea of where the high-priced sales were. Go back into the symbology window and experiment with manually changing the colors and sizes of the dots. Also make a copy of the theme and try mapping the data using "Graduated Color" instead of "Graduated Symbol." Which method do you think is better?

IV. Getting Your Work on (virtual) Paper

Configure your data display window to show Income shaded thematically, Cambridge TIGER, sales89, and Camborder. Turn off all other layers. Now you are ready to make a map. Under the View menu select Layout View. You get a default map layout in the data display area. We've worked with data layers in the data view, and now we are working with a layout document. Although we can print a map directly (using the Print command under the File menu), it is impossible to control exactly how it will look on the page without using a layout. Besides the GIS layers, a layout usually also includes a title, legend, scale bar and north arrow. These are the most basic components of a map.

This default map layout has no title, scale bar or legend. You can either insert these components one by one or apply a template. Let's first apply a template. Click the second to the last button on the layout tool bar, which is "change layout".

Fig. 14. Layout Tool bar

Select "LetterLandscape.mxd" under Traditional Layouts tab and click "finish" button.

This template adds legend, North arrow and scale bar to the map layout. But the map title is still empty.

To add the title, double click on Double click here to enter the title. In the text box of the property window, type in Lab Exercise 1.

Additionally, we need to add a few more elements to the map:

• the sources of the data
• subtitles
• your name
• today's date

Let's add the data source first. Click Text under the Insert menu. A small text box shows up in the middle of the map. Double click the text box to bring up the property window. In the Properties dialog box that comes up, type:

Sources:
U.S. Bureau of the Census, 1990
Banker and Tradesman Real Estate Transfer Database, 1987-1989

Note that you can use the Enter key to insert line breaks in the text. Once you click OK, the text is placed wherever you clicked in the layout window. You can move this text by dragging it with the mouse. You can double click on the text, bring up the property window and change the font and size until you are satisfied.

In the same way, we can add two subtitles. Underneath the title Lab Exercise 1 add two subtitles in smaller text that read "Median Household Income in Cambridge, MA in 1990" and "Housing Sales in Cambridge, MA in 1989." Also add your name and today's date somewhere on the map.

Feel free to move and resize the elements to make your map look more attractive. the default symbology and color choices have not resulted in a particularly effective map. You can also go back to the symbology window to adjust the existing symbology. Once you change the symbology, the change will be applied to the map layout automatically. You don't need to create the layout again. Try your best to make the map readable and attractive. Although it is hard to make a real attractive one this time, we expect your map should be much better than than Fig. 16.

Before you print out the map, make sure to clear any 'selected' features -- these will show up highlighted in yellow on the map. Any selected features will also show up highlighted on your printout, which you probably don't want.

Now you can print your map - or save it as a PDF file. Select Print from the File menu. Click Setup button and select the name of a printer that is proximate to the room where you are doing the lab (see "Printing Notes" below) and click the OK button. In our case, we do not need a physical printout - just a PDF version of what would be printed. (When you do print, be aware that getting predictable colors on the paper output isn't always as easy as you'd think. You can't be sure it will work until you have the piece of paper in your hands and you may need to tune the software to match the printer's color capabilities.)

Printing Notes

Actually, there is no need to generate printed hard copy for the class. All the exercises will be submitted electronically to the class homework locker on Stellar. CRON machines have a 'printer' named 'Adobe PDF' that, instead of printing a document, saves it in PDF format within a folder of your choosing. In addition, ArcMap allows you to 'File/export' a map layout in PDF format.

All Athena clusters have access to physical printers via a system called 'Pharos' that controls the routing of your printout. See this website for further information about how to print from Athena machines. The 9-554 computer lab is a CRON facility and has its own printing services but uses a system similar to Pharos. See this website for further information about printing from CRON machines. Basically, after 'printing' you must release a print job for printing on a particular machine.

Your file(s) containing your lab exercise #1 can be uploaded to Stellar later this week when we have provided access to you to the class homework turn in area on Stellar.

V. Save Your Work

Remember to save your work again by clicking the "File / Save as..." menu option (and, after that, the disk icon). ArcGIS can save the status of your session in the map document file, which typically has a .mxd extension. The map document file does not contain the data sets itself, but rather stores pointers to their locations. Your thematic map properties and layouts are also stored in the document file.

After you have done more work on a map document that you previously saved, you could save your changes under a different name by using Save As instead. Try this now, saving a copy of your map document as lab_1copy.mxd. Saving variations of your map documents under different filenames is a good practice. The map document files themselves are typically not too large, so making lots of map document files should not waste too much disk space and provides some recovery help if your working document gets corrupted.

Next time, when you reopen the map document file with ArcMap, it should look just the same as when you saved it this time. You can try it now if you have additional time.

VI. Overlaying your Map onto Google Earth

Also, you could overlay the map file onto Google Earth. The ArcGIS Toolbox provides conversion tools that allow you to write out an ArcMap layer or ArcMap document in a format that can be read by Google Earth, Google Maps, and other map viewing applications that adhere to the 'KML' protocol for representing mapable 3D data. (KML stands for Keyhole Markup Language. Keyhole was the company that originally developed what became Google Earth. KMZ is the compiled version of KML.)

To locate the 'Map to KML" window (shown above in Fig. 17), we need to use the ArcToolbox search tool. Choose the "Geoprocessing / Search-for-Tools" menu option. A search window will open up on the right hand side of the ArcMap window. Enter "kml" and search for "Map to KML". Double click on the 'map to KML (conversion)' choice. (You may see an "script error" window open up with complaints about invalid characters in a java script. This message can be ignored - just click "Yes" to continue.) If the dialog box in Fig. 17 does not open up, choose "Geoprocessing / ArcToolbox " to open the ArcToolbox window and find the "Map to KML" tool in the "Conversion Tools / To-KML" section. Set the Map Document to be lab_1copy.mxd (in what ever directory you have saved it) and set the Data Frame name to be whatever Label is shown for the Data Frame in ArcMap (if you never renamed the data frame, it will be called "Layers." Finally, set the output to be lab.kmz within a writeable directory. Set the 'layer output scale' to be '1' so the layer is always turned on. Now, open Google Earth Pro and click File/Open to navigate to wherever you saved lab.kmz and open the file. If you saved the KMZ file to a web-readable directory such as the 'www' sub-directory of your Athena locker, then you could also open lab.kmz in Google Earth via 'Add/Network-link' using this URL: http://mit.edu/your-athena-id/www/lab.kmz

Finally, save and turn in a screen shot of the Google Earth screen once you have zoomed in to the Cambridge area and can see the your thematic map.One way to grab a screen shot is to use the "snipping tool" under "Start / Programs / Accessories".

VII. Interpreting Maps Published in the Press

We are done with the parts of this exercise that involve your preparing and visualizing maps. But we would like you to spend a little time examining and commenting on some map that you have encountered online. You are free to select the online map as long as you include a publicly-accessible URL with your exercise (so we can see the map!). You may also choose to use any one of the map-related links that were provided in the lecture notes during the first day of class.

In a few paragraphs, please do the following:

(a) Provide the URL for the article of your choice and for one of the thematic maps included in the online article,
(b) What assertion (about some spatial pattern) is the map intended to portray?
(c) Briefly describe the choice of classification method and color choices used to construct the thematic map. (If the classification method is not stated, make and explain your educated guess.),
(d) Comment on whether the data source and thematic map are reasonably convincing regarding the assertion. Would you have preferred an alternative classification method? .. more caveats in the text? ...a different spatial scale? ...a more realistic baseline comparison? etc.

VIII. If You Finish Early

If you finish the lab assignment with time to spare, you may want to return to this layout window and experiment with the other templates and various styles of the map components.

Checking out more of the ArcGIS online help (started from the Help menu) is also a good idea. Throughout the class we will expect you to try to answer your own questions about ArcGIS by consulting the online help and the class notes before asking the class staff. Of course, if you get stuck, we are here to help and we do not want you to be stuck for long!.

IX. Lab Assignment

Turn in to your lab assignment on the 'homework' portion of the class Stellar site: The lab assignment consists of the ArcMap layout that you produced in Part IV, the Google Earth overlay in Part VI, and your comments on an online thematic map in part VII. The lab assignment is due by the START of class on Tuesday, Feb. 21, 2017 (which follows the Monday schedule that week!). <<< The due date is EXTENDED ONE DAY until 2:30 pm on Wed., Feb. 22, 2017, due to the snow storm on Feb. 13. >>>

For today's lab, we loaded shapefiles and coverages directly from the class locker into ArcMap. Since we are only using small datasets, leaving them on the network locker does not result in a big performance hit. But it is risky, as well as slower, to use data layers in ArcMap that reside on network lockers. In the future, we will make a habit of copying are working files to c:\temp (or a locally mounted external drive) before adding them to ArcMap. This practice will speed up performance and reduce the likelihood that ArcMap crashes after a disk 'timeout'. However, we must then remember to copy any newly created or altered datasets or ArcMap documents (*.mxd files) back to our network locker, flash drive, or the like before we logout and leave the lab.

Created by Raj Singh.

Modified for 2001-2017 by Thomas H. Grayson, Joseph Ferreira, Jeeseong, Jinhua Zhao, Xiongjiu Liao, Mi Diao, Yang Chen, Yi Zhu, Lulu Xue, Eric Schultheis, Melissa Chinchilla, and Hongmou Zhang.
Last Modified on 8 Feb. 2017 by Hongmou Zhang and Juan Camilo Osorio..

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