2. Data Queries Selecting features in ArcMap

3. 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 Raster Data Query

4. Attribute Data Query  SQL (Structure Query Language) is used select records from an attribute table  Structure (syntax) of the query language  Select (select field or column)  From (defines a table)  Where ( some condition or criteria) Select name 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 Select from the “name” field in the “counties” table, where the values=“Monterey”

5. Query Expressions  Boolean Expression Combination of field, value, and an operator Name = Monterey Pop2000 >= 400,000 State_Name = Calfornia  Boolean connectors Keywords that connect two expressions State_Name = California AND Pop2000>= 400,000 State_Name = California OR Pop2000>= 400,000

6. Query Expressions – Boolean Connectors - AND State_Name = California AND Pop2000 >= 400,000 AND - satisfy both criteria - intersection

7. Query Expressions – Boolean Connectors - OR State_Name = California OR Pop2000 >= 400,000 OR - satisfy either one or both criteria - union

8. Spatial Data Query 3 Ways to select features spatially  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)

9. Working with selected features 1.create new selection 2.add to currently selected features 3.remove from currently selected features 4.select from currently selected features You can add, remove or select from currently selected features using location and attribute queries.

10. 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

11. 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: M anually using the cursor Select by graphics Select by Location dialog