Querying your Data
The Table of Contents offers advanced Query capabilities to draw a subset of your data or make a selection.
Restart the Education National Web App by opening this URL:
Expand Map Layers
Expand NationalData
Turn on the Schools Layer and expand it to view the Legend.
All the Schools from all the States are displayed on your map.
What if you wanted to display only the Schools in the State of Arizona?
Open the Menu Options for the Schools Layer.
Select Information
This opens a summary table for the Schools Layer showing the main Properties and their Values.
This is a Point Feature Layer.
The REST URL is:
There are no minimum and maximum scale thresholds for this layer.
All points will draw at all scale levels.
Pick Select/Filter by Attributes
This opens the Query Dialog window where you can specify your SQL expressions.
Click on the down arrow to list the fields.
Select Field = LSTATE
Set Operator is equal to
Click on the down arrow to see a list of States and select AZ
Click to Validate your Query
Your Query is valid.
The server returns 2000 records. This is a server limit.
You have the option to make a selection or filter what gets drawn on the map.
Select Filter Map Using Query
Only the Schools in Arizona are drawn on the map.
What if you wanted to select all Schools in Maricopa County?
Once again, pick Select/Filter by Attributes from the Layer Menu.
Click on the down arrow to see a list of fields.
Select COUNTY
Set Operator is equal to
Scroll down the list and select Maricopa County.
Notice the number that appears next to the County names.
It indicates the number of Schools within each County.
Validate Query
There are 1312 Schools in Maricopa County.
Click on Select Using Query to select these 1312 Schools in Maricopa County.
You have 1312 Schools selected.
Open the Menu Options.
Select Show in Table
The Attributes of all 1312 Schools are displayed in a Table.
Open Menu Options
Rename the Tab
Enter a meaningful name like Schools in Maricopa County
Click on the Schools Layer to view the 1312 selected Schools.
The 1312 selected Schools in Maricopa County are highlighted in cyan.
They are a subset of all the Schools that are displayed in Arizona.
Click on the Black Mountain Elementary School.
The attributes of Black Mountain Elementary School are displayed below.
Black Mountain Elementary School is highlighted in cyan on the map.
Open the Menu Options for Black Mountain Elementary Schools.
You will find options to Pan/Zoom and Buffer your selection.
