Selecting features in ArcMap Data Queries Selecting features in ArcMap

Data queries Important part of a GIS project Can be a part of your data preparation or final analysis Data Queries (selecting data based on a question or criteria) Attribute Query Spatial Data Query

Attribute Data Query SQL (Structure Query Language) is used select records from an attribute table Example of a SQL statement for retrieving data Select * From counties Where NAME = Monterey Query Expressions Boolean expressions Combination of field, a value, and a logical operator (=, +, - , etc..) Boolean connectors (AND, OR, XOR, NOT) Connects two expressions The structure or syntax of sql consist of keywords that are strung together for form a statement. Here is a common SQL statement.

Query Expressions Expression Connectors Combination of field (column), value, and an operator Example: Name = Monterey Pop2000 >= 400,000 State_Name = Calfornia Connectors Keywords that connect two expressions State_Name = California AND Pop2000>= 400,000 State_Name = California OR Pop2000>= 400,000

AND Connector State_Name = California AND Pop2000 >= 400,000 AND - satisfy both criteria - intersection

OR Connector State_Name = California OR Pop2000 >= 400,000 OR - satisfy either one or both criteria - union

Spatial Data Query 3 Ways to select features spatially (by location) Feature selection by cursor - (select features tools) Feature selection by graphic - (draw a graphic and use it to select features) Feature selection by spatial relationship Containment (fall within a feature) Intersect (intersect a feature) Proximity ( within a specified distance)

Working with selected features create new selection add to currently selected features remove from currently selected features select from currently selected features You can add, remove or select from currently selected features using location and attribute queries.

Isolating your selected features Permanently save your selected features save as new data file (shapefile or geodatabase) Right-click on layer  data  Export data Temporary save your selected features create a temp layer in your ArcMap project as Right-click on layer  selection  create layer from selected features One extra step …. --- to create a .lyr file Right-click on layer Save As Layer File

Summary of selection types Select by attribute using SQL In ArcMap you can find this in the: Selection menu Attribute table Definition query – displays data only Located in the layer’s properties Spatial Query: Manually using the cursor Select by graphics Select by Location dialog