In this lesson, you'll start a new map in ArcMap and locate your study area of Rondônia, a Brazilian state in the Amazon rainforest. Then, you'll add data layers and visually examine satellite imagery to become familiar with the geography.
Find the study area
First, you'll start a new map, become familiar with ArcMap's user interface, and find the project's study area.
- Start ArcMap.
If you don't have ArcMap, you can get it by purchasing ArcGIS Desktop from the Esri Store.
The ArcMap - Getting Started window opens. This window allows you to open previous maps or map templates.
- Close the ArcMap – Getting Started window.
A blank map opens. Above the map are toolbars. By default, the Standard and Tools toolbars are turned on. To the left of the map is the Table Of Contents, which shows the geographic content of your map. Like the map, the Table Of Contents is empty.
If you've used ArcMap before, your interface may be arranged differently.
Next, you'll find the study area for this project: Rondônia, Brazil. Rondônia is located in the Amazon rainforest, so adding a layer of the Amazon is a good start. You'll add a layer from ArcGIS Online.
- On the Standard toolbar, click the arrow next to the Add Data button and choose Add Data From ArcGIS Online.
The ArcGIS Online dialog box opens.
- In the search box, type Amazon Ecoregion and press Enter.
- In the list of results, find the result titled Amazon Ecoregion by Learn_ArcGIS and click Add.
The layer appears on the map as a large orange shape. These are the boundaries of the Amazon ecoregion, but it's not clear where in the world the boundaries are located. Next, you'll add a basemap. A basemap depicts background reference information such as landforms and political boundaries. It can help show your data's location in the context of the world.
- On the Standard toolbar, click the arrow next to the Add Data button and choose Add Basemap.
- In the Add Basemap dialog box, click Imagery and click Add. Close the Geographic Coordinate Systems warning.
If the Hardware Acceleration dialog box opens, click Yes. This will allow your basemap to draw faster.
The Imagery basemap is added to the map and the Table Of Contents under the Amazon Ecoregion layer. It uses satellite imagery as reference information. With the basemap, you can see the Amazon's location in South America. The area inside the Amazon is much greener than the area outside. Most of the Amazon rainforest is dominated by dense tree canopy.
You still don't have enough data to find Rondônia on the map. You'll add another layer showing the states of Brazil.
- Click the arrow next to the Add Data button and choose Add Data From ArcGIS Online.
- Type Brazilian States in the search box and press Enter.
- Find the result titled Brazilian States by Learn_ArcGIS and click Add.
The layer appears on top of the Amazon Ecoregion layer. However, some of the layer extends beyond the current map extent, or zoom level. To see the whole layer, you'll zoom out.
- On the Tools toolbar, click the Zoom Out tool.
When you move the pointer over the map, it becomes a magnifying glass.
- Click anywhere on the map. Click the map again.
The map zooms out and centers on the location you clicked. You're zoomed out far enough to see the entire layer, but the layer may not be centered in the map frame.
You can also zoom using the mouse's scroll wheel. Depending on your screen resolution and monitor size, you may need to zoom more to see the entire layer.
- On the Tools toolbar, click the Pan tool.
When you move the pointer over the map, it becomes a hand.
- Drag the map until the Brazilian States layer is in the center.
Unlike the Amazon Ecoregion layer, which has only one feature, the Brazilian States layer has twenty-seven features. Features are discrete representations of a real-world object on a map. In this instance, each state is a feature. Features also contain attribute data, which describes the feature's characteristics.
- On the Tools toolbar, click the Identify tool.
- Click any state on the map.
The state flashes green and the Identify dialog box opens.
The Identify dialog box shows the attribute data, or information, for the feature you clicked. Although you can identify states until you find Rondônia (if you were lucky, it may have been the state you clicked), you can use a quicker method to find a feature with a specific attribute.
- Close the Identify dialog box.
- On the Tools toolbar, click the Find tool.
The Find dialog box opens.
- In the Find dialog box, on the Features tab, type Rondonia in the Find box. Click Find.
At the bottom of the Find dialog box, a list of matching values appears. The list contains one item called Rondonia.
- Right-click the Rondonia value and choose Zoom To.
The map zooms to the Rondônia feature in the Brazilian States layer, highlighted in the following image:
- Close the Find dialog box.
Organize and symbolize the data
Currently, you can't see the basemap under the Brazilian States layer. You'll change the layer's symbology to better see your layers. You'll also organize the layers in the Table Of Contents.
- In the Table Of Contents, locate the Brazilian States layer.
The Table Of Contents lists all layers in the map. It also shows the layer's symbology and any groups that organize the layers. In this case, the Brazilian States layer is in a group also titled Brazilian States. Layers added from ArcGIS Online are placed into groups by default, but a single layer doesn't need to be grouped.
- Right-click the Brazilian States group and choose Ungroup.
The layer is ungrouped, which changes only how the layer is organized in the Table Of Contents.
- Right-click the Amazon Ecoregion group and choose Ungroup.
Because the Imagery layer is a basemap, it can stay in the Basemap group. Next, you'll change the symbology of the Brazilian States layer.
- In the Table Of Contents, click the symbol for the Brazilian States layer.
The Symbol Selector dialog box opens. It includes a list of preset symbols and some symbology options. You'll give the Brazilian States layer a symbol with only an outline, similar to the Amazon Ecoregion layer.
- For Fill Color, choose No Color.
- For Outline Width, highlight the existing value of 0.40 and type 1.50.
- For Outline Color, choose Arctic White.
On the color palette, you can see the name of a color by pointing to it.
- Click OK.
The symbology changes. The Brazilian States layer now has only a white outline.
The Amazon Ecoregion layer (the orange line) is beneath the Brazilian States layer (the white lines). Layers are drawn on the map in their order in the Table Of Contents.
- In the Table Of Contents, drag the Amazon Ecoregion layer above the Brazilian States layer.
The Amazon Ecoregion layer appears above the Brazilian States layer.
- Examine the map.
When the map was zoomed to South America, the area inside the Amazon Ecoregion layer appeared greener than the area outside. In Rondônia, however, a large portion of the land is grayish-brown terrain, with the green regions mostly in the northern and western parts of the state. The large, barren-looking area is deforested.
Although the land looks barren, it is actually not. While deforestation in the Amazon does occur for extractive purposes, such as acquiring lumber, a lot of deforestation clears land for cattle grazing or perennial agriculture. Most of the seemingly barren terrain is actually pasture or farmland.
The soil quality in the region is poor and quickly depleted of nutrients. As such, it is difficult to regrow Amazon rainforest after it has been deforested. To protect the rainforest, prevention of future deforestation is key.
Add and symbolize the Cities layer
You've found your study area. Now, you'll add a layer showing cities in Rondônia and symbolize it to show the largest cities by population.
- On the Standard toolbar, click the arrow next to the Add Data button and choose Add Data From ArcGIS Online.
- Type Rondonia Cities in the search box and press Enter.
- Find the result titled Rondonia Cities by Learn_ArcGIS and click Add.
The layer is added to the map above the other layers. It contains points of various colors, each representing a city in Rondônia. Most cities are in deforested areas.
- Locate the Cities layer in the Table Of Contents.
Like the Amazon Ecoregion and Brazilian States layers, the Cities layer is in a group by default (the group is called Rondonia Cities).
- In the Table Of Contents, right-click the Rondonia Cities group and choose Ungroup.
Unlike the other layers, the Cities layer has four symbols instead of one. Layers can be symbolized based on attribute data. In this case, the attribute is Population_2014. The labels next to each symbol indicate the range of population each symbol represents. The lighter red symbols are for cities with lower populations, while the darker red symbols are for cities with larger populations. You can find the population of each feature using the Identify tool, or you can see the attributes of all features with the layer's Attribute Table.
- In the Table Of Contents, right-click the Cities layer and choose Open Attribute Table.
In the Attribute Table, attributes are organized into columns, or fields, and features are organized into rows.
The fields give the name of each city, its 2014 population, its latitude, and its longitude. The OBJECTID and Shape fields are managed by the software. The populations of the 52 cities in Rondônia range between 2,000 and 500,000.
- Close the table.
Symbolizing the cities by color is okay, but it would be more intuitive if the cities were symbolized by size, with larger symbols indicating larger populations.
- In the Table Of Contents, right-click the Cities layer and choose Properties.
The Layer Properties dialog box opens. This dialog box includes more symbology options than the Symbol Selector you used earlier.
- At the top of the Layer Properties dialog box, click the Symbology tab.
The symbols are set by Quantities, which classifies attribute values into ranges and gives each range a unique symbol. Currently, those symbols have graduated colors, but they can be given graduated symbol sizes instead.
- Under Quantities, click Graduated symbols.
The symbols retain their ranges and labels, but now have random default graduated symbols. Next, you'll change the size and color of the symbols.
- Click the Template button.
The Symbol Selector opens.
- In the list of preset symbols, click Circle 2.
- Change the color to Arctic White.
- Click OK.
The four circles range in size from 4 to 18 points. The smallest symbol is difficult to see.
- Above the list of symbols and ranges, change the Symbol Size range to be from 8 to 20.
- At the bottom of the Layer Properties dialog box, click OK.
On the map, the largest cities tend to be in the middle of the deforested area, although they range in distribution from north to south. Smaller cities tend to be closer to the edge of the deforestation.
Lastly, you'll change the Population_2014 attribute in the Table Of Contents. Your eventual goal is to share your data as part of a finished map, so renaming the attribute to something more presentable is important.
- In the Table Of Contents, under Cities, click Population_2014 once to select it. Click it a second time to make it editable.
- Type Population (2014) and press Enter.
The attribute is renamed in the Table Of Contents. Its name in the Attribute Table remains unchanged.
Download additional data
You've added reference data to your map. Next, you'll add data to be used in your analysis of the relationship between roads and deforestation. Rather than add this data directly from ArcGIS Online, you'll download it to your computer.
- Go to the Get Started with ArcMap group.
The Get Started with ArcMap group contains one item: a file geodatabase called Rondonia. A geodatabase is a spatial data format that stores geographic data.
- Click the thumbnail of the Rondonia item to download it.
The item downloads as a compressed file folder.
- When the download finishes, find the compressed folder and extract its contents to a location you can easily find.
- In ArcMap, to the right of the map, click the Catalog tab.
The Catalog window opens. The Catalog is a directory of files, tools, servers, and services associated with ArcMap. It allows you to organize and access files for your map. To add geographic data from your computer to a map, you need to connect to the folder where the data is stored.
To keep the Catalog docked to the right of your map, click the Auto Hide button (the pin icon) on the title bar of the Catalog window.
- On the Catalog window toolbar, click the Connect to Folder button.
- Browse to the location of your Rondônia folder. Click the Rondônia folder (not the geodatabase) and click OK.
Depending on where you extracted the data, your path will be different than the example images.
The folder is added to the Catalog under Folder Connections.
- Click the plus sign next to the folder connection to expand it. Then, expand Rondônia.gdb.
The extension .gdb stands for geodatabase. In the Catalog, geodatabases have a gray cylinder icon.
The geodatabase contains four feature classes and one raster dataset, which can be added to the map as layers. You'll learn more about raster datasets later. Feature classes are groups of features sharing similar attributes and geometry, like the Brazilian States layer. The term layer refers to a map representation of data, while feature class refers to the file-based data itself. Feature classes come in three main types: point, line, and polygon.
Before you add the data to your map, you'll set the Rondônia geodatabase as the default geodatabase for your map document. The default geodatabase is the location where new datasets are saved by default.
- In the Catalog window, right-click Rondônia.gdb and choose Make Default Geodatabase.
Next, you'll add some data to the map.
Add and symbolize the Roads layer
Next, you'll add a layer of roads. There are two main types of roads in Rondônia: Official roads, built by or with the permission of the government, and unofficial roads, built independently of the government. Because your ultimate goal is to determine the potential deforestation caused by a proposed road, looking at existing roads is vital to your final analysis.
- In the Catalog window, drag the Roads feature class to the Table Of Contents, below the Brazilian States layer.
When you add a layer from your computer it has random default symbology. Your symbology may vary from the example images.
The Roads layer contains a dense network of roads that covers most of the state. The layer doesn't extend past the Amazon Ecoregion boundary.
- In the Table Of Contents, right-click the Roads layer and choose Open Attribute Table.
Among the fields are Name and Status. Status shows whether a road is official or unofficial. Unofficial roads do not have names, although official roads might. The number at the bottom of the table reports the total number of features: 27,662. Which roads on the map are official and which are unofficial? You could use graduated symbology options to give each type of a road a unique appearance, or you could use an attribute query to select all features in a layer with a certain attribute.
- On the ArcMap main menu, click Selection and choose Select By Attributes.
The Select By Attributes dialog box opens. It has many options and can look complicated at first. You'll become familiar with its interface before you use it.
In this dialog box, you build a logical expression to determine the attribute by which features will be selected. In the topmost box are the field names in the selected layer. Below it are the logical operators, which define the relationship between two things. To the right of the logical operators is a box that displays the unique values of a field you select, and the bottom box contains the expression.
Using these options, you'll create an expression to find roads where Status = Official.
- For Layer, choose Roads from the list.
- In the list of fields, double-click Status.
The word Status appears in the box at the bottom of the dialog box.
- In the list of logical operators, click the equal sign (=) button.
An equal sign appears next to the word Status. Next, you'll add the unique value of Official.
- Next to the list of logical operators, click Get Unique Values. Double-click 'Official' to add it to the query.
The word Official in single quotation marks appears in the box at the bottom. Your query should look like the following image:
- At the bottom of the Select By Attributes dialog box, click OK.
Official roads are selected (highlighted in blue) on the map.
Official roads appear to connect municipalities and facilitate travel between population centers. Although they mostly appear in deforested areas, deforestation does not solely occur in places where there are official roads. There appear to be significantly fewer official roads than unofficial roads.
The ability to see official roads independent of the total road network is useful reference information. However, a selection is not permanent and will be erased if you make another selection or deselect the features. To prevent this, you'll make a new layer based on the selection.
- In the Table Of Contents, right-click the Roads layer, point to Selection, and choose Create Layer From Selected Features.
The Roads selection layer is created and added to the top of the Table Of Contents.
- On the Tools toolbar, click the Clear Selected Features button.
The original selection is cleared. It may have the same symbology as the original Roads layer, so you may not be able to see it in the map.
- In the Table of Contents, click the symbol for the Roads selection layer to open the Symbol Selector. Scroll through the preset symbols and click the Stacked Multi Roadway symbol.
- Change the color to Seville Orange.
- Click OK.
The official roads cover up the cities. Also, the Roads selection layer should be renamed to better reflect what it shows.
- In the Table of Contents, click the name of the Roads selection layer to edit it. Change the name to Official Roads.
- Drag the Roads selection layer below the Brazilian States layer and above the original Roads layer.
Lastly, you'll change the symbology of the original Roads layer.
- In the Table Of Contents, click the symbol for the Roads layer to open the Symbol Selector. In the list of symbols, click the Arterial Street symbol.
- Change the color to Raw Umber.
- Click OK.
The difference between official and unofficial roads is clear. Unfortunately, the unofficial roads still clutter the map. Because the official and unofficial roads are now in separate layers, you can turn off the Roads layer to temporarily hide it while keeping the Official Roads layer visible.
- In the Table Of Contents, uncheck the box next to the Roads layer.
You can turn the layer back on at any time by checking the box again. For now, you'll leave it off.
Save the map
Next, you'll save your map so you can return to it at any time.
- On the Standard toolbar, click the Save button.
The Save As dialog box opens.
- Name the map Amazon Deforestation and save it in the same location as the Rondônia folder that you downloaded.
The map document is saved with the extension .mxd, which is the standard extension for ArcMap map documents.
In this lesson, you started a new map and added boundary layers to locate your study area. You added layers of infrastructure that will be important for analysis and general map information. In the next lesson, you'll take a closer look at the relationship between deforestation and roads to find a pattern you can apply to the proposed road.