Querying your data

1. Querying your data Class 9 GISG 110

2. Objectives Querying your data • Tools for examining your data • Identify, Find, Measure, map tips • Promoting and displaying selected records • Working with selection tools • Why do you need a selection • Available selection tools • Selection methods and layers • Spatial selection • Attribute selection • Graphic selection

3. Getting Started Query • To ask questions about • especially in order to resolve a doubt • In ArcMap, queries are similar to selections • Difference • Definition queries display features based on selected criteria (and hide the rest) • Selections highlight selected features, while others are also displayed

4. Identifying • Displays attributes for any feature you click on as pop-up attributes

5. Locate a specific feature or attribute Search all layers or a specific layer Choose how you want feature displayed with the context menu Finding Egypt flashes Right-click the value, context menu appears

6. Find linear distances Cassablanca to Capetown, through Agadez Measuring

7. Status bar reports length of each segment as it is created and total length line when finished Measurements use pure Cartesian coordinate system Expect some errors Measuring Status bar

8. A display property of a layer Map tips Pointer location displays specific attribute To set: Layer Properties Display Tab  Show Map Tips Map tips

9. Why do we need a selection? • Using the selected set for further analysis • Using the selected set to select other features • Editing the selected set • Creating a new layer from the selected set • Working from a subset is faster than entire set • Calculating statistics for the selected set • Creating a report • Exporting the selected set to a separate format

10. Making queries • Selects records from tables and features from layers

11. Promoting records • Displaying selected records: All or Selected

12. Displaying selected records • Selected records from tables also select features from layers

13. Existing selections can be broadened or narrowed Additional query criteria Modifying selected sets

14. Two tool sets Manual select using Select Features tool Selection pull down menu Four ways to select graphics in ArcMap Interactively Attributes Location Graphics Available selection tools

15. From Selection menu Set Selectable Layer Specify layer(s) to select from using interactive selection tool Selection layers Method 2 Method 1

16. From Selection menu  Interactive Selection Method Create new selection Add to selection Remove from selection Select from selection Interactive Selection Method

17. Selection methods • Select by Attributes… • Select by Location… • Select by Graphics…

18. Use a SQL “where” clause to select features Save and reload selection expressions Field Value Operator Attribute selection

19. Use features in one layer to select features in another Select by location (spatial query)

20. Location selection methods • Select by location offers many selection methods • Intersects • Contains • Are contained by • Shares a line segment • Touch boundary • Within a distance • Are identical • Others… Polluted areas “completely within” selected counties

21. Selection by graphics • Draw a graphic to select features • Select by graphic Rivers in Madagascar

22. Selection menu  Options Select features partially or completely within the box or graphic(s) Select features completely within box or graphic(s) Select features that the box or graphic are completely within Selection Options

23. Complete features are selected, whether they fall completely or partially within box Complete features are selected only if they fall completely within selection box Selection box must fall completely within feature to get selected Select by Graphics Options

24. Review • What is a Map tip? • What does the Identify tool do? • How do you access the context menu in the Find tool? • What are the four ways a feature can be selected in ArcMap? • What type of statement does the Select by Attribute function use to select features? • If I wanted to find the number of stop signs within a 2 mile distance of 4th and B St, what selection method would I use? • To select by graphics, a search is performed on the records in the attribute table based on the selection criteria typed in the selection statement. (T/F) • List two reasons why we need to perform selections. • All measurements in the Measure tool, are in pure Cartesian coordinate system. (T/F) • Making queries selects records from tables and features from layers. (T/F)

25. Remainder of Class • Break • ESRI Chapter 8 Querying data (8a & 8b only) • ESRI Chapter 10 Selecting features by location • Exam review

26. Exercise questions • What language are queries written in? • What is the difference between interactively selecting and writing a query? • To select features by location, you only need one layer. (T/F) • How many spatial relationships does ArcGIS define as variations of the original four types (distances, containment, intersection, and adjacency)? List them. • What is the difference between a definition query and an attribute query? • Creating a definition query does not affect the data source. (T/F)