The ArcGIS Predictive Analysis Tools Add-In is available for download. The ArcGIS Predictive Analysis Tools Add-In is a set of tools used by analysts to build models to predict the location of moving or stationary targets or events. You can … Continue reading
Water Utilities often want to identify where pipes of a certain material and/or diameter exist in their system or where hydrants out of service or in need of repair are located. Did you know you could to do this using ArcGIS Online? As a GIS technician/analyst/manager, how much time would it save you to empower your users to do this themselves; as a user, how much time would it save you to do it yourself? Follow the steps below to learn how to create a Filter Application in ArcGIS Online. Continue reading
The ArcGIS Viewer for Silverlight development team is excited to share a new query tool for the Viewer on ArcGIS Online. This tool allows users of the Application Builder to interactively build queries against ArcGIS Server services, presenting end-users with a simple dialog box that prompts for values to plug into the query.
ArcGIS Explorer Online enables you to select sublayers and apply a query filter to a service, letting you choose just want you want and also allowing you to change symbols. In this example we’ll take a look at how we can use these capabilities to create a custom hazard map using the USGS Natural Hazards map service.
We’ll start by opening a new map, and then add the USGS Natural Hazards service by searching using the keyword “hazards” as shown below. Click Add to show it on your map:
Yesterday’s magnitude 5.8 quake, centered in northern Virginia, shook a vast corridor along the East Coast. The temblor prompted us to take a closer look at the USGS hazards map service, one of many published by the USGS on ArcGIS Online.
First we started Explorer Online and opened a new map, then searched for “USGS hazards” to find the USGS Natural Hazards layer which we added:
This service contains several other feeds relating to hazards, including volcanoes, hurricanes, wildfires, and more. But we were only interested in the quakes so we opened the layer details to turn the other layers off:
How often is the data updated? It was easy to find out by clicking Service Details which opened the service description from the source at usgs.gov.
The well-documented service included a link to a USGS website that provided information about the various hazard information sources and update intervals. We learned the earthquakes are updated every 10 minutes, and the service includes all that have occurred in the past seven days of magnitude 2.5 or greater.
The quake was a 5.8 (downgraded from the originally reported 5.9) and we were wondering how many other quakes of equal or greater magnitude might have occured over the past week. To discover this we used an Explorer Online query.
Clicking New Query we chose Earthquakes from the list of sublayers from the USGS:
And constructed our query to find those of magnitude greater than or equal to 5.8 by choosing the field, operator, and value as shown below:
We could have chosen to “hardwire” the query to the 5.8 value, but we wanted a little more flexibility so we decided to enable the user to enter the value they want by accepting an input for the magnitude. We checked the box to prompt for value and entered a prompt string and hint as highlighted below:
When executed the query results will be displayed along the right of the map.The currently selected feature in the result list is highlighted in red, others matching the query are highlighted in blue. The sample map shown below includes two different earthquake queries.
To show the queries saved with the map click the query button:
For more information see the following help topics:
Queries are one of the powerful new features of ArcGIS Explorer Online and enable you to ask questions to find specific features that match your query. Queries can be of two types – either hardwired, where the query is predefined and can’t be changed, or parameterized, where the user can enter values to complete the query. We’ll provide an overview of both here.
We’ve saved the map used in this example so you can open it and follow along.
First start ArcGIS Explorer Online and add the earthquake service from the USGS. We found that particular service using Search and entering “earthquakes.”
Select the earthquake layer, open the Tools tab, and look for the Query tool on the far right of the ribbon.
Click Query and select the layer to query against. There is only one layer in our map named Earthquakes from last 7 days. This is the name of the service we added to our map above.
Once selected, the query for the layer can be constructed. Click the Query tab (highlighted in blue as shown below) and choose magnitude as the field to query. Also choose >= as the operator, and enter 3 as the value. The query appears in the Expression box.
Clicking OK adds the query to our map, and also executes it. Highlighted in blue are all the earthquakes greater than or equal to 3 in magnitude.
The query is saved with our map and we can execute it at any time by double-clicking the query. The query has properties just like any other map item, and we can change its name by right-clicking and choosing Rename. Below we’ve chosen to rename it Earthquakes >= 3 to make it obvious what the query returns.
Another type of query is a parametric query. We can use these to create queries that accept input from the user that will return the results based on a variable input. In this next example, we’ll create a query that prompts the user for the magnitude of the earthquakes to be found.
As in the first example select the earthquakes layer, open the tools tab, and click query. This time click the Parameters tab (show as step (1) below) and then follow along with the numbered steps.
(1) Choose the Parameters tab
(2) Click New to create a new parameter query
(3) Choose a field from the dropdown list. In this case we chose magnitude.
(4) Choose the operator from the dropdown list. Here we have chosen >=
(5) Enter a default value. The user can input their own value, but this is the default that will be used.
(6) Create a prompt. The prompt is what the user sees when they execute the query.
(7) Provide a hint. The hint appears if you hover over the input box that appears after the prompt string.
After you’ve completed the above, click the Query tab then select the parameter query you’ve just created above, and click OK. The expression will not display, but you’ll see the number in brackets that identifies the parametric query you’ve just created.
When you use the query you’ll see the prompt, default value, and hint as shown below:
And just like in the previous example we can rename the query to provide more context.
You can open the map used above and experiment for yourself.
For more information about queries, you can view the following Help topics which provide additional details.
Ask questions with queries (also includes a video tutorial)
About queries (includes other links to more details)