ArcMap | Learn GIS

Overview of ArcMap - Data View

Data view is where you will spend most of your time when you are working with ArcMap. This is the view where you can best interact with you data.

Here is the basic layout of ArcMap in Data View

Connecting to Folders

In order to see inside your folders, you need to give ArcGIS "permission" to look inside those folders. We call the permission action connecting to a folder. In ArcGIS, this is an active process, with the need to connect to each folder you wish to use. The process does, however, honor all folders below the folder you connect to, which means that if you grant permission for the C: folder on a computer, you can access everything saved on the C drive. You can't, though, connect to "Computer" and access everything. You need to connect to each drive folder, if that is what you'd like to do. For this class, we will connect to the GIS 101 folder right from the beginning. As long as you sit at the same machine each week, you shouldn't have to connect each time (only if the permission is forgotten), but you move from machine to machine, you will have to reconnect to see your work.

Note: You need to connect to a folder, not a layer, not a geodatabase, and not an MXD. When you are looking at the connect box, just find your GIS101 folder, click to highlight, and click OK to connect.
In order to disconnect from a folder, right click on it’s name in ArcCatalog and choose “Disconnect Folder”

Creating Simple SQL Expressions

Open the Select by Attributes dialog box
OPTONAL - Define the Layer as “States” if the dialog box was opened from the Selection Menu
Find the Field Name “State_Name” and double-click to add it to the Expression Builder
Single click an operator, in this case “Equals”
Click the button to populate the box with unique values
Type a “M” into the box
Scroll through the list to find Massachusetts (or type the “assa” to jump right to it)
Double click to add ‘Massachusetts’ to the Expression Builder, already enclosed in the ‘required single quotes’
Click the button to check for syntax errors
If the expression was successfully verified, click the button to make the selection
Click the button if you have completed your selection, or use the selection type to remove or add to the selected values via a new expression.

Result: “State_Name” = ‘Massachusetts’

Click to Hide/Show Animation

Selection Methods

Create new selection	Selects only the feature for which the values fit the query criteria and clears any other features which may be currently selected Most of the time, we are performing new selections, and that is what the dialog box defaults to.
Add to current selection	Selects additional features by means of another query and adds it to the list of selected features. Add to current selection can be used an endless amount of times within one table, well, at least until all the features are selected and there are no more to add to the list.
Remove from current selection	If there is a current selection (features highlighted in the table), remove from current selection will deselect any features which match a new query. This method would be used when you need to select some features, examine them, and decide which ones to move forward with by using another query. Multiple queries can be used sequentially to reduce the pool of selected features until only the final selection is left.
Select from current selection	Similar and opposite to remove from current selection, Select from Current Selection re-selects features you do want based on a new query instead of removing them from the list.

Comparison Operators

Operator	Button	Purpose
Equals		Returns all features with a value in the specified field which exactly matches the value defined in the expression. Record values are case sensitive and spelling dependent, meaning “california” is not the same value as “California” nor “Kalifornia”. An attribute table will see these as three separate values and each value must participate in a different expression. Equals works for numeric, text, and date/time type fields.
Not Equal To		Returns all values except the defined value. The opposite of Equals. For numeric field types, the expression looks for values which are not equal the defined value; for text type fields, not equal to looks for all words that are not the defined word; for date/time type fields, not equal to looks for dates or times which occur any time other than the defined date/time.
Greater Than		Finds values greater than the defined value not including the defined value. Works in numeric type fields, text type fields where greater than is based upon alphabetical order, for example, State Name greater than ‘California’ will return all the features with a state name Colorado to Wyoming, alphabetically; and date/time fields.
Greater Than or Equal To		Finds all the values greater then AND equal to the defined value. In our example, State Name Greater Than or Equal To ‘California’ will return California to Wyoming, alphabetically. Works for numeric, text, and date/time type fields.
Less Than		Finds all values less then the defined value but not including the defined value. For example, State Name Less Than ‘California’ will return Alabama to Arkansas, alphabetically. Works for numeric, text, and date/time type fields.
Less Than or Equal To		Finds all the values less then AND equal to the defined value. For example, State Name Less Than or Equal To ‘California’ will return Alabama to California, alphabetically. Works for numeric, text, and date/time type fields.
LIKE		LIKE is used to find values within an attribute which are similar to, instead of exactly like, the value defined in the expression and is used in conjunction with the wild card values _ or %. In order to find all values that end in “alifornia”, an expression such as - "State_Name" LIKE ‘_alifornia’ - will return the features where the State Name attribute is “california”, “California”, or “Kalifornia”. Another example might be - "Owner_Name" LIKE ‘Br%’ - which will return the values “Brett”, “Brent”, “Brandon”, “Brendan”, and “Brant”
Wildcard (One Character)		The underscore _ is used as a wild card value when building SQL expressions, meaning it can replace a single character such as “C” when attempting to locate “california”, “California”, or “Kalifornia”.
Wildcard (Many Characters)		The % sign is used as a wild card value for variables that contain two or more characters, meaning Br% can replace the the “ent” or “ant” when attempting to locate the man’s name “Brent” or “Brant”

Logical Operators

Operator	Button	Purpose
AND		When building complex expressions, the AND logical operator is used to combine two (or more) simple expressions together to find a feature for which both (or more) expressions are true, meaning if an expression is built to find State Name = ‘California’ AND State Name = ‘Colorado’, the query will look for a feature named both California AND Colorado. AND is used to build complex expressions such as State Population greater than or equal to 65000 AND State Area less than 125000 - which will return only states with a population greater than or equal to 65000 AND have a total area less than 125000 square miles.
OR		OR is used to combine two (or more) simple expressions together to find features that meet any of the criteria defined, meaning if an expression is built to find State Name = ‘California’ OR State Name = ‘Colorado’, the query will look for a feature named either California OR Colorado.
NOT		Used to find values that are not (any of the available operators) to the value defined in the expression. Similar to the Not Equal to button, NOT can be used in front of an expression to make it not equal or not equal to or greater than the defined value, such as NOT State Name less than or equal to ‘California’ will return Colorado to Wyoming, alphabetically - which is the same as greater than . NOT, instead, is most often used in combination with LIKE, such as Owner Name NOT LIKE ‘Br%’, which will return every name in the list that does not start with “Br”.