Geography

Learning Goals

In order to see how many datapoints fall within a town or county or other geographic unit, you can join two layers of your map not based on the data on their tables, but based by whether or not they intersect with a region on the map. This is called a Join by Location. 

Scenarios that this is useful for include ones where you have datapoints associated with a specific place or event that you want to provide additional context for based on the data available about their surrounding towns, cities, counties, states or other regions. Maybe you're investigating a past outbreak of a disease and want to take the datapoints you have representing documented cases and associate it with zip codes so you can instead of looking at every given point and trying to draw a conclusion, visualize which zip codes had the most cases. Maybe you're doing a study on urban farming and want to visualize which census blocks have the most farms. Maybe in both of those cases you have underlying data about those zip codes or blocks that you'll want to use as context to understand why there are more sick people or urban farms in those places, like median income or population density. These are cases where spatially joining your data points in one layer to geographic features in the other can come in handy. 

In this case, you have individual data points on the map related to receipts by certain law enforcement agencies of former military equipment via the 1033 program. You have data about felony drug-arrest rates but only on a county-level basis. In order to ask the question if law enforcement agencies in counties with high felony drug-arrest rates request larger values of equipment, you'd need to determine which counties these agencies were located within. Since you have the boundaries of these counties already drawn on your map, with the Join By Location function you can add a new layer that compiles all the data for points falling within each county. 

For this exercise you'll be using the map we created in the last exercise, but if you didn't do that one, the map is below.

Data

Getting Started

• Open GraduatedSymbols+1033Data in ArcMap, and check and uncheck the boxes associated with each of the layers in the Table of Contents window to familiarize yourself with the data on them.
  • LEA Totals - Quantity contains graduated symbols about the total quantity of items received by each law enforcement agency
  • LEA Totals - Value contains graduated symbols about the total acquisition value of items received by each law enforcement agency
  • 1033 Data_Original - has the acquisition values for each individual shipment stacked on top of each other for each law enforcement agency

For the map you want to wind up with that visualizes the total acquisition value for all items acquired by the law enforcement agencies within the county 103Data_Original is the layer that you'll want to be joining to the Counties layer in your basemap. Since there isn't a separate field in this table that contains data about which county this law enforcement agency falls into, you'll need to do this based on these datapoint's spatial location.

Joining a Table to a Layer Based on Spatial Location

• Right-click on the Counties layer in Base Map from NY.GOV and choose Join.
• In the Join Data  window change the first dropdown from Join from attribute table' to Join data from another layer based on spatial location.
• Chose the layer  1033Data_Original since that has each police station's location and each record of a shipment associated with it.
• There are two options below for how you want to go about this join. Select the first option: Each polygon will be given a summary of the attributes associated with the points that fall inside of it. This creates a join where the resulting feature class will have a summary of the values associated with the datapoints that fell within that county. 
• Select Sum as the attribute that you want. For other kinds of studies, you might want to use one of the other options. Maybe if you're entering in price data for produce items at markets in blocks in New York City, you'd be most interested at the average price for a produce item within that block.
• In the last item on the Join Data window, use the folder icon to navigate to where you want to save this file and choose a name for it. I've chosen TotalsByCounty.shp as the name of my shapefile. Click OK.

The new TotalsByCounty shapefile will be automatically added as a layer to your map, but it will originally just appear as a flat symbol. You'll have to go in and change the symbology of the layer to have it display the total of value of the equipment acquired in each county.

Adding Symbols to a Polygon Layer

• Uncheck all your other layers except for your Base Map from NY.GOV group layer to make them invisible
• Double-click on the TotalsByCounty layer to open the Layer Properties window and select the Symbology tab
• Go to Graduated Symbols in the Show menu. Select Sum_Acquis as the Value to display. This is the field you created in your previous exercise that has the sum total of the acquisition value of items for all the datapoints that fall within that county . Use the Classes dropdown to give it 7 classes.
• Click on Label, and off that menu click on Format Labels. Set the category as Currency and click OK 
• Click on the dot under Template and change the Color to Mars Red. 
• Click on the patch below Background, and switch the symbol to Hollow, since you want to put another layer of information underneath this map.

When you finish, your map will look something like this

A reason to make the background underneath the graduated cells transparent is so that you can then put other county-level data beneath it, like population, economic or demographics data, or in the case of the attribute table that is associated with the County shapefile in this document, per capita drug arrests. 

Visualizing County Layer

• Double-click on Counties in the Base Map from NY.GOV layer to open the Layer Properties window. 
• Choose the Symbology tab and navigate to Quantities > Graduated Colors. 
• For the Value select ArrestsByP, since this field contains the number of arrests per capita for each county in 2012. For a full map you'd want to make sure the data matched up with the year-range of the study, but just for this demonstration we'll use the number we already have associated with the sheet. 
• In the Classes dropdown select to make 7 classes. Click on Label at the top and select Format Labels. In the Rounding section use the up and down buttons to make it so that only 2 decimal places will be showing. Click OK.
• When your Layer Properties window looks like the below, click OK

You'll get a map that looks something like the below, which allows you to display two kinds of data at the same time, but because it uses different methods of visualization it's still pretty clear to read. You can tell by looking at a county how much the items it received were valued at and the level of drug arrests per capita that it had. 

However, look closely at the scale for the symbols. You're not quite done yet. Notice how the low end of the first scale is set to 0. Is that because they didn't receive any equipment or because they received equipment that didn't have an acquisition value? Currently, you don't know, however, there is a way to correct this so only items that received any equipment from the 1033 program show up on this map and that is by using a Definition Query on your layer. 

Using a Definition Query

A Definition Query lets you define which parts of your data will be shown on the map. This can be useful to you when you're working from a large data set where only a subset of the data in it is of interest to your project. In this case, you only want to display dots on counties where they received at least some equipment from the 1033 program. You could have tackled this by creating an invisible symbol to be used for the class of $0 in acquisition value however, it is possible that some counties only received equipment that didn't have an acquisition value assigned to them, and you would be leaving out areas pertinent to your study. What you need is to find the column that will tell you if any of the LEA totals at all were located within that county, and use that to build a query. 

• Right-click on TotalsByCounty and select Open Attribute Table
• Take a note of the contents in each column. It looks like Count_ is the one you need, but scroll down, were there any occasions where Count_ was valued at 0 and any of the other columns contained information. When you get to the bottom, you'll see that the answer is no. If the Count_ field has a value of 0, that means there were no data points within that county so these are the counties you'll want to leave out of your map. 
• Double-click on TotalsByCounty and in the Layer Properties window navigate to Definition Query. Click on the button Query Builder
• Scroll down to "Count_" and double-click to add it to your query. Remember you only want items where the Count_ is greater than 0 because that will mean there was at least one datapoint within that county. Click on the > button to add that function to your query. Use Get Unique Values to see the measures in that field. They don't have quotation marks around them which means that ArcGIS recognizes them as numbers. Double-click on 0 to add it to your query.
• Your query should be  "Count_" > 0
• Click on Verify and if it tells you that the expression has been verified, click OK
• In the Definition Query tab, your expression will now be within the formerly blank window. Click Apply
• If you left your Attribute Table open you'll notice that there are now no items where Count_ is 0 left. 
• Click back to your Symbology tab and click where it says Classify. You'll have to reconfigure how it is classified since the former one was based on the older definition of the data, so change it from Natural Breaks to something else, and then back again and click OK. 
• Click OK in the Symbology tab and when you exit you'll notice that now there are some counties on the map with no dot. This means that according to your data, they never received materials from the 1033 program.

Save your map now. Remember, always be on the lookout for inconsistencies in your map. Are you leaving somewhere in that doesn't apply to your research question? Are you leaving something out that does? 

You can see the map as I've configured it saved below.

Learning Goals

When you've uploaded a sheet with multiple fields, it can get a little daunting to figure out what you want to be visualizing about your places of interest. If you have a table you downloaded from the census with population, economic and demographic information for an area across a five year span, you might only be interested certain years, or certain measures or certain counties. You can make decisions on the fly in ArcGIS about which maps are pertinent to your research question, without editing this data in a separate program before uploading it . 

In this exercise you'll learn how to select only certain categories of information, to export those selections as their own layer, and by using data frames be able to switch between different maps created by selections from a single table.   

As mentioned in the previous exercise, the drug arrest rates by county that I have visualized on my county map are from 2012, but the data I have about what law enforcement agencies acquired from the 1033 program comes from many different years. What if you just wanted to visualize the total value of items acquired by the different counties in 2012 and 2013? Instead of creating new sheets in Excel with just the data for those years, in ArcGIS you'll use the Select by Attributes function to look at just shipments made in those years and export a new layer with only that subset of your data. Then, by putting each in their own data frame, you'll create the groundwork to create a layout with a side-by-side comparison in the next exercise.

Start from this modified selection of data created previously below

Data

Getting Started

• Open ExportingNewLayersAnd1033Data.mxd in ArcMap. You'll see that it has a series of dark green dots representing the shipments going to law enforcement agencies from the 1033 program and the group layer underneath that is the base map with the outlines of counties, villages and cities and towns. 
• Click on the Identify and then click on one of the green dots. You'll see that one green dot represents many shipments and you can see that there is additional information on each of these shipments including the year it was shipped
• Right-click on 1033Data and choose Open Attribute Table. This is where you can see how the table is set up, note that for each Station there are multiple shipments and the data on what year the shipment was sent is held in a field called Ship_Year.

Since the data we have in our counties on the basemap has the drug felony arrest rates for 2012, the useful data to see if there is any relation between a high drug arrest-rate for New York State and more costly equipment being sent to that county would be to look at the shipments sent in 2012 and 2013. We'll want to pull the data for just these years and use them to create separate layers for the map. 

Selecting By Attributes

• Click to the menu item Selection and choose  Select by Attributes. This opens a window for you that gives you the opportunity to put in an SQL query to select a part of your data. Don't know what SQL is? No problem, the buttons on the side will make it easy for you to make an SQL query. 
• You are looking to create a new selection within the 1033Data layer, so leave that layer selected, and leave the default Method of Create a new selection
• You want items shipped in 2012 or 2013, so those are the values you want in the Ship_Year field.  Scroll down the list of field names and double-click on the one marked "Ship_Year". That puts that field into your query. 
• Click on the button that says 'Get Unique Values' in order to put a handy list into the window to the right of all the values available in that field

• So since what you want is items with either 2012 or 2013 in Ship_Year, you can either by typing it out or clicking on the corresponding buttons enter into the selection query window

"Ship_Year" = 2012 OR "Ship_Year" = 2013 

• Click Verify to make sure that the equation is correct. When the pop up window says it is, click OK

In this instance you are looking for numerical information but this doesn't need to always be the case. If you instead only wanted to select items with a certain text value in the field you could do that instead, like if you only wanted items coded MOTOR VEHICLES,CYCLES, TRAILERS in the FederalSup field, you could have made that selection. It also doesn't need to be a complete match if it is numerical information, you could select only items over a certain acquisition value. You can string multiple requests into the same query, combining several of these together to look only for vehicles valued over a certain amount shipped within a certain year range.

Select By Attributes is a very useful tool for you to customize your map to only show information that is pertinent to your research question. Definition Query  serves a similar function, however when you Select by Attribute, the information not within the selection is still visible on the map, it just isn't highlighted. But back to this query - 

• After you click OK, you'll notice that some points are now highlighted in bright blue on the map and some aren't. Additionally some lines are highlighted in bright blue on the table, and some aren't. If an item is highlighted in bright blue that means it has been selected because it matched the parameters of your query.

Since these are the items you want on your new layer, these are the selections you'll export.

Exporting a Selection as a Layer

• Right-click on the 1033Data layer,  choose Data > Export Data. 
• Make sure the Export dropdown is set to Selected Features. Change the Output feature class name to 1033_for_2012_2013 so that you can later tell what it is. Change the folder you want to save it to if you don't like the default
• After it exports, it will ask you if you want to add the new layer to the map, click Yes. To see the difference between the two, uncheck the box for 1033Data. You'll see some of the dots disappear. Close the attribute table for 1033Data if you haven't already. 

Now that you only have the data for 2012 and 2013 on the map, you'll be able to make a map that only contains those pertinent years. 

Symbolizing Quantities within Categories

• Double-click on 1033_for_2012_2013 to open the Layer Properties window, and proceed to the Symbology tab. 
• If you want to create symbols that at a glance tell the viewer what year the shipment was sent to the law enforcement agency and the amount of money that shipped equipment was valued at, you want to choose Multiple Attributes, Quantity by Category. Click to go to that menu
• The division you want to make is between 2012 and 2013 items so the Value Field you'll want to choose is Ship_Year. Click Add All Values, you'll see those two years and <all other values>. Uncheck the box next to <all other values>.  
• Double-click on the symbol next to each year and make them light and contrasting colors. Since these symbols will be stacked on top of each other, and will eventually be on top of a map containing a spectrum from blue to red, you'll want to make colors that will stand out on top of that too. I've chosen Medium Apple for 2012 and Heliotrope for 2013. This edits the color the symbol will be
• The quantity associated with each symbol can make it larger or smaller or change its color on a spectrum. Since you want to vary the size of the symbol so it's more easily discernible at a glance, you'll click on Symbol Size under Variation.
• In the dialog box that opens up, I'll select Acquisitio as the field I want to use the value for, and will set Classes to 7 in the dropdown. I'll leave the default Symbol Size in that varies from 4 to 18 points. Click on Label and select Format Labels. Select that the Category is Currency and click OK. Check the box to Show class ranges using feature values and click OK to exit the Symbol Size menu. 
• Click OK on the Layer Properties menu and you've visualized the acquisition value for each of the years shipments.

Your map should look something like this if you've chosen the same options I did, but you can certainly vary the scales or colors you use or whether you'd rather display the quantity of items received. 

Displaying Quantities Data for a Polygon Layer

If you've done the previous exercises you've already changed the symbology in the Counties later, so just do the same thing you did the last time you visualized the Arrests per 100,000 data for the Counties layer, but if not see below.

• Double-click Counties in Base Map from NY.GOV to open the Layer Properties menu, and select the Symbology tab. 
• Choose Quantities > Graduated Colors in the menu for what you want to Show. 
• Select ArrestsByP as the Value you want drawn. Pick 7 as the number of Classes you want in the dropdown. 
• Click on Label and choose Format Labels. Use the up and down arrows to select that you want the number of decimal places to be 2 and click OK

• When it looks like the above, click OK

You now have a map that looks like the below, where a viewer can tell at a glance what the acquisition value of shipments for law enforcement agencies in a county in 2012 and 2013 were as well as what the per capita felony drug-arrest rates were in that county in 2012.

Please note however that without summarizing, your viewer would need to click on the symbols on the map to see the total items received across shipments, so if you want to visualize the total acquisition value for all shipments for the law enforcement agency, you'd need to use the Summarize function described in the first module for this tutorial. If you want to visualize the total acquisition value of all items received in the county, you'd need to do the Join by Location function described in the previous module. 

Looking at this map, it's hard sometimes to tell if one of the larger dots from one of the years is obscuring a smaller dot from a different year. To be able to look at your data more clearly, you'd want to separate these into a layer for 2012 and one for 2013. In order to eventually be able to display a side-by-side comparison of the two, you'll also want to put each in their own data frame.

Creating Another Data Frame

• Go to Insert and select Data Frame. Name the new frame 2013Data. It will appear empty, in your Table of Contents window.
• Right-click on your original data frame Layers and choose Properties. In the General tab, change the name to 2012Data.
• Click to highlight each of the layers in 2012Data, right-click and choose Copy
• Right-click on the data frame 2013Data and choose Paste Layer(s)

Now that you've created a data frame for each year you'd like to explore with your data, you'll change the layers in each so they only reflect 2012 for one and 2013 for the other. 

Using Definition Query to Narrow the Data Displayed.

A Definition Query is used on a layer to define the data it will be displaying amongst the data available for it to display.  Similar to Select By Attribute, you can select based on what values are in a field, either from a list of acceptable values, or if the values are numbers, those above or below a certain threshold. You can turn it off or on at any time but while one is on, your map will only display a selection of your data.

• To make sure it's clear which layer you are editing, change the 1033_for_2012_2013 layer at the top of each of your data frames to read 2012Data_Acquistion for the one at the top of the 2012Data data frame, and 2013Data_Acquistion for the one at the top of the 2013Data data frame
• Double-click on 2012Data_Acquistion to open the Layer Properties window and navigate to the Definition Query tab. Click on Query Builder below the blank box in that tab
• The Query Builder dialog box probably looks familiar since it operates on the same SQL Query language used in the Select By Attributes function used in the beginning of this lesson. Since you want to narrow this down to just include the records with '2012' in the Ship_Year field, you'll scroll down to "Ship_Year" in the window at the top of this box, and double-click it to add it to the query. Click on the = button. Use the Get Unique Values button to populate the box with the values available in that field, and double-click on 2012 to add it to the query.
• Now your query should look like:  "Ship_Year" = 2012
• Click Verify. If the expression is validated, click OK in the Query Builder box, and then Apply for the Layer Properties.
• Go to the Symbology tab and click on Add All Values. 2013 should disappear from the symbols.
• Click to the Symbol Size menu, and switch the classification from Natural Breaks to one of the other options, and then back again to recalibrate it. Your map should now only have the green dots representing 2012 and the scale not listing as broad a range as previously. 
  • If this doesn't appear, check if the 2013Data data frame is in bold font on your Table of Contents. If it is, that means that is the active data frame, and you'll have to switch to your 2012Data data frame in order to see changes. Right-click on 2012Data and select Activate. 
• ​​​Repeat this process in your 2013Data_Acquistion layer, only instead of the query being for "Ship_Year" = 2012 it will be for "Ship_Year" = 2013.
• Save your document.

.Now you can right-click and select Activate to switch between your two views, so the two will stop overlapping. The other benefit of data frames will be made clear to you in the next exercise, they can be used to create new layouts with multiple maps on them.

If you want to see how I constructed this, the map document is below.

Learning Goals

While on some occasions you'll be presenting only one map that you have created with your data, on others, for example for poster sessions, you may be adding in multiple maps that represent your data. Rather than taking screenshots of individual maps, using Layout View and multiple data frames allows you to present your maps in a unified fashion while still being able to customize and fine-tune the geographic aspects of your maps. 

In a tutorial in the first module, Visualizing Data on a Map, you learned how to create a map when you had only one data frame. After completing this one you'll learn how to create a layout with multiple dataframes, thus allowing you to create a layout containing multiple maps. You'll add individual map elements for each data frame and make sure that the scale is as consistent as possible across both so that you are creating a unified picture of what information each presents.

We'll be using the attached map document to start with which is a modified version of the maps created in the last exercise

Data

Getting Started

• Open ForLayout_2DataFrames.mxd
• Take a look at the Table of Contents window. Rather than there just one top data frame - Layers with all the layers for that data frame underneath it, there are two, one called 2012Data and one called 2013Data. This is because since the data is concerning the same spots, for it to be on the same map meant that some data would be obscured. So in the last exercise, we created two data frames so you can swap back and forth while working on your findings for that project. This configuration of multiple data frames also lets you create a layout where the two maps appear side by side, letting the viewers draw comparisons.

Starting in Layout View

• Go up to View on the menu bar and click on Layout View.

At first you'll see the two maps overlapping something like this.

• Go up to File and choose Page and Print Setup. Change Orientation to Landscape. Click OK
• With this new configuration, you'll want to add some guides within your layout in order to make sure you're creating a balanced composition. A guide is a straight blue line that will run across your layout horizontally or vertically at whatever distance in from the edge that you want. It won't show up when you print your map, it's just there for your own guidance. Go up to View and make sure that there is a outline next to the option Guides to signify it is turned on. Make sure that Rulers is turned on too. 
• You can add a guide to your layout by clicking at the point on the ruler where you want a line drawn across your layout. You can click and drag the arrow that appears at the beginning of the line on the ruler if you want to readjust where it appears.
  • Click to create a guide at the top ruler at 5.5 inches, so that each map gets half of the screen.
  • Create a guide about .75 inch from the top of the page on the ruler on the left to leave room for the title, and about .5 inch from the bottom to leave room for your sources.
  • Add one more guide about 3.5 inches from the bottom so that you have room to add the legends. 
• Click on each of the different data frames, and move and resize them so they fit in to the two equal-sized boxes in the top half of the page you drew for them with the guides.Place the 2012Data data frame on the left (the one with the green dots) and the 2013Data data frame on the right (the one with the purple dots).
• When you have clicked within a data frame so it's selected, the zoom to full extent, pan and zoom in and zoom out tools are going to work on the map within the frame. Click on the globe icon (this is zoom to full extent) in each. That does still leave a border around the edge of the map. If you are eager to get each map as large as possible, you can fine-tune using the pan tool and to change the scale at the top of the map. 1 in = 80 mi worked for me to get it really close to the edge of the margins.

When you've finished that, it will look something like this

Adding Text Elements to Your Layout

• A title will tell the reader what they are looking at.  Go to Insert in the menu bar and choose Title.  A pop up window will appear asking you what title you'd like, and type in

  ---

  2012 and 2013 1033 Receipts by Law Enforcement Agencies and Felony Drug Arrest Rates, 2012

• ---

   Click and drag the resulting box to the middle of that section at the top that you set aside for the title.  Use the text toolbar up top to change the size and color of the font to make it larger and stand out. I changed the font size to 17 and changed the color to Dark Navy.

You also will need to add text letting your viewer know where you got your information from. This lets people know if you are using credible sources, and lets other scholars to engage with your work and do work that builds off of yours. Maybe they are working in a similar area and when they see that you have statistics on felony drug arrest rates or acquisitions of decommissioned military equipment by police departments they'll want to know where they can can find similar information for their own geographic area or time period that they're interested in. You can convey this information by adding source text

• Go up to Insert on the menu bar and select Text. It will put a small box somewhere in the middle of your view that just says 'Text'.
• Drag this box down to the space at the bottom that you set aside for it.
• Double-click on the Text box, and it will open a properties window that will let you alter the text.
• When working on your own project, you'll need to go to the Credits section of your different layers to find the sources used to make your map. That is if you used best practices and consistently kept track of your metadata.
• If I were pasting from the credits section, I could just write
  "Sources: NYS Office of Information Technology Services GIS Program Office (GPO); Division of Criminal Justice Services, New York; New York Department of Health;Defense Logistics Agency, Law Enforcement Support Office."
• Note, however that the text will not be wrapped, so you'll need to press enter about in the middle, experiment to see how it fits. Click on the left-align button to make sure it's left aligned. Click OK, and the Sources text should appear at the bottom of the map.
• You'll want to make sure you give yourself credit too of course. So put in your name as the author. Click on the Insert menu item and choose Text
• Click and drag it on top of the two boxes containing your data frame, and center it across them. Double-click to open your source window and type "Map by" and your name.
• Use the font dropdown at the top of the map to increase the size of the font and re-position it if necessary

Creating the Legends

The way for people to understand what the different symbols mean is to insert a legend which will explain what the symbols in each layer represent.  However the legend's information is going to come from the scale, the titling and the headings you have for your layers in your Table of Contents. To have clear explanatory text on your legend, click on the titles and headings on each of the visible layers in your Table of Contents, and change the language to make it very clear what the symbols in it are representing

You'll now create a separate legend for Total Value of Items Shipped to LEAs by County, 2012 to go under that map frame on the left, for Felony Drug Arrest Rates by County, 2012 to go between the two since the same scale is on both maps, and the last legend for Total Value of Items Shipped to LEAs by County, 2013.

• Right-click on 2012Data and choose Activate.Whichever data frame that you have activated is the one that the Legend Wizard will draw from with what can be included in the Legend.
• Go up to Insert and choose Legend.   
• Since you just want this Legend to contain your LEA acquisition value data, highlight Felony Drug Arrest Rates... on the left hand window where your Legend items are and click on the left-pointing arrow to move it off the list. Set the number of columns to 2. If you click on the Preview button first, it'll put a preview version of the legend on your layout so that you can see how the changes that you are making are changing your legend. Click Finish.
• Double-click on the Legend on your sheet to open the Legend Properties window. In the General tab, delete Legend from the title field, you don't need that title
• In the next tab Items, double-click on the Total Value of Items... within that first menu to open Legend Item Properties. In the General tab, un-check the box for Show Heading. The layer name already conveys that it's the total value of items, you don't need to additionally say beneath it that it's acquisition value. Click OK
• Click to the tab Layout and check the box next to Wrap labels. Click Apply. The title for your layer is very long, so if it can wrap you'll be able to fit your legend in a smaller box.
• Click to Frame and using the dropdown menu under Border change the border to be .5 point. Click OK  at the bottom of the Legend Properties box.
• Now you should have a box at the bottom containing the legend for that layer. Click and re-size and move if you want. Notice that the font-sizes will change to fit the new size of the legend as you do so
• Right-click on 2013Data and choose Activate.  Follow the same procedure above to create a legend for Total Value of Items Shipped to LEAs by County, 2013
• Move that legend over to be under the right-hand map.
• Follow the same procedure to create a legend for Felony Drug Arrests Rates by County. One exception though, do not un-check the box for Show Heading. 
• Move that legend to be centered between your other two. Click to adjust 

Adjusting the Legends

The Legend boxes that you create do not contain layer information in their own right. They are dynamic. If you change the symbols or turn a layer off or on using the Table of Contents view, the legend's labels, titles, and symbols will change accordingly. This comes in handy because sometimes until you see all the legends together on your map you won't realize that something about them needs to change.

From a cursory look at the map with the scales the way they are, it looks like there was a lot more valuable equipment shipped in 2012 than 2013. Sure, more of the symbols on the right hand map are larger rather than smaller but it's not like they're giant in comparison.

Examine the scales for the symbols for the Total Value of Items Shipped for 2012 and 2013, specifically at the maximum and minimums of each scale. Notice anything?

In 2012, the smallest value of total equipment sent to law enforcement agencies in a county was 300.28 and that class capped out at 3,808. In 2013, the smallest value of total equipment sent to law enforcement agencies in a county was 10,000 and that class capped out at 18,712,47. The same sized symbol on each map for the minimum number represents very different amounts in terms of the value of equipment. The largest symbol on the map in 2012 represents a class that has a maximum of $360,084.96. The largest symbol on the map in 2013 represents a class that has a maximum of 1,449,307. Though these symbols both are the same size, because they are for scales drawn up for the variation between total amounts within their own maps, they are not to scale between each other and that can lead to a misleading picture.

Let's change the 2013 classifications so that they are a more accurate comparison to the 2012 numbers. 

To make things easier on ourselves, let's just change the 2013 classifications. But first we'll need to take a look at the sizes given to the symbols in the Total Value of Items Shipped to LEAs by County, 2012 layer.

• Double-click on Total Value of Items Shipped to LEAs by County, 2012 and navigate to the Symbology tab.
• Double-click on each of the symbols to open the edit menu for it and see what size it is set to and write it down. You'll be adjusting the scale of the symbols on the 2013 layer accordingly. Click OK to get out of this window.
• Double-click on Total Value of Items Shipped to LEAs by County, 2013 and navigate to the Symbology tab.
• You'll want to both change up the classifications so you are closer to the class boundaries used in the 2012 map, and change up the symbol sizes, since halfway through the 2013 scale you already have a higher total value than the maximum for 2013.
• Change the maximum on the Symbol Size from  25 to 33 to give yourself some room to work with since you already know that the maximum-sized symbol in 2013 should be larger than the one in 2012
• Since the 2nd class on the 2012 scale (19,300-41,061) is closer to the minimum class on the 2013 scale (10,000-18,712), increase the minimum on the scale to 9 to place the size somewhere between the 1st and 2nd classes. 
• You'll need to do a bit more adjusting of the sizes so click on Classify. You can adjust the break values by manually typing them in Break Values or moving the bars in the histogram window in the middle. 
• I adjusted the classes to have a maximum as follows. You can choose another way if you want, and then click OK to go back to the symbology menu. 
  • 1st class - unchanged
  • 2nd class - 177,628
  • 3rd class - 480,000
  • 4th class - 688,894
  • 5th class - 1,281,993
  • 6th class - 1,449,307
• You'll next want to change the symbol sizes. You can do this by double-clicking on the symbol for the class you want to change, and then typing in the number of points you want it to be. Completely proportional comparison would mean for very inconveniently large symbols in the 2013 map but in this way you can at least indicate that there is a large difference between the maximums in the two maps, by making the symbol for the third class larger than the maximum for 2012. I've made them as follows
  • 1st class - 9
  • 2nd class - 18
  • 3rd class - 25.5
  • 4th class - 28
  • 5th class - 30
  • 6th class - 33

You can experiment with different class boundaries and symbol sizes to create your own picture.

Adding Scales and North Arrows

These basic navigation aids are less crucial on thematic maps like these that won't be used for navigation. A reader, however, might still want to know the distance between different counties and whether the map is in the typical configuration with North being straight up so it is helpful to add these. 

• Right-click on the 2012Data data frame and choose Activate. Go to the Insert menu and select Scale Bar activate it
• This opens the Scale Bar Selector and you can scroll through the options on it. I'll pick Alternating Scale Bar 2 but if you want to choose a different one, that's fine. If you want to customize it further, click on Properties. In that window you can decide if the measure is miles or kilometers, choose how many divisions you want and where they are on the line, along with other options. I'll use the defaults. 
• When your Scale Bar is added to the layout, drag it to the lower left corner of your 2012 map, and resize it to fit. The nice thing is it will automatically size down the amount of miles it displays to stay accurate.
• For the North Arrow, go up to the Insert menu and select North Arrow. It will open up the North Arrow Selector. There are a lot of options to scroll through but I like the one that is the N with the Arrow in the circle, ESRI North 55, so I'll choose that.  Click OK and when it appears in your layout, drag it to the lower left corner of your 2012 map. Just like with the scale, the North Arrow is dynamic, so if you change what direction your map is pointed, the North Arrow will change too. 
• Right-click on the 2013Data data frame in your Table Of Contents and choose Activate. This will ensure that the Scale and North Arrow that you are about to add are for that data frame and not the 2012Data one. Not a big deal for this project, but it will matter if you are working on a project where your data frames have different scales or orientations.
• Repeat the procedure to insert a Scale and North Arrow for your 2013 map as well.  You may want to add Guides to make sure they're aligned across the maps
• When you've gotten all of your elements aligned to your liking, clear all the Guides on your project by clicking on one of the arrows on each ruler (top and left) and choosing Clear All Guides.

You've now created a suitable layout for your project, it should look something like the below.

The way I constructed it is attached below, but please explore different manners of configuring your symbols and legends and titles and navigation aids to construct the map a different way if you prefer a different look.