Getting to Know Web GIS. Pinde Fu
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Pop-ups
Pop-up windows are considered windows to show geographic information and deliver geographic insight. They are a common tool that your end users rely on to interact with your operational layers. Today’s users click or tap a location or feature on the map and expect to see a pop-up showing more information.
The default pop-up appearance for a layer is a plain list of attributes and values. You can configure the pop-ups to show custom-formatted text, attachments, images, and charts and links to external web pages. These pop-ups enhance the attributes associated with each feature layer in the map and present the information in more intuitive, interactive, and meaningful ways.
ArcGIS Arcade
How do you display data when there is no column in the schema containing that data? Traditionally you would have to alter the underlying data, such as adding a new column. But if you are not the owner or don’t have the privilege, you can’t alter the data. Arcade solves this common problem. Arcade is a portable, lightweight, and secure expression language written for use in the ArcGIS platform to style layers, label layers, and add values to layer pop-ups. With Arcade, you can build custom expressions based on existing fields and geometries without having to alter the data. Here are a couple simple examples:
Label the percentage of the young and elder in the total population.Round(($feature.AGE_5DOWN + $feature.AGE_65UP)/ $feature.TOTAL_POP * 100 ) + “%”
Calculate the weekday of the crime events in a layer.Weekday($feature.Reported_Date_Time)
You can almost think of Arcade as “Microsoft Excel for ArcGIS.” In much the same way that Microsoft Excel lets you write formulas to work with spreadsheet data, Arcade lets you do the same with layer attributes and geometries. Like other expression languages, it can perform mathematical calculations, manipulate text, and evaluate logical statements. It also supports multi-statement expressions, variables, and flow control statements. Arcade was designed specifically for creating custom visualizations and labeling expressions in the ArcGIS Platform, including ArcGIS Online and ArcGIS Enterprise.
With Arcade, you can build custom expressions, use them to configure your layer style and pop-up without having to alter the underlying data.
While the syntax contains similarities to other scripting languages, Arcade is not designed for writing stand-alone apps. It is intended solely for evaluating embedded expressions such as those used in visualization, labeling, and alias contexts within applications of the ArcGIS platform. For more details, refer to https://developers.arcgis.com/arcade/guide.
Web app user experience design principles
User experience is an important factor when you configure your web layers, maps, and apps. A good Web GIS app should deliver informative content and enhance necessary functionality for a fast, easy, and fun user experience. Story Maps facilitate your creation of web apps with pleasant user experiences.
Fast: “Don’t make me wait,” say today’s users. Web GIS apps should use caching, database tuning, appropriate client/server task partitioning, and load balancing to achieve optimal performance, scalability, and availability. When you use ArcGIS Online, these are mostly taken care of by Esri for you automatically. But these aspects are important checkpoints when you use ArcGIS Enterprise to host your own layers and apps.
Easy: Today’s users also say, “Don’t make me think about which button to click,” and “If I don’t know how to use your site, it’s your problem, and I will leave the site quickly!” Web GIS apps should focus on a specific purpose. Do not overwhelm users with unnecessary buttons and data layers. Make the user interface intuitive. The interface should provide feedback, such as visual cues, that lead users through a well-defined workflow and assure them that they are on the right track.
Fun: Integrate photos, charts, videos, and animation into your web apps. Used properly, these media enhance user engagement, convey your key information, and improve user satisfaction.This tutorial
In this tutorial, you will learn how to create a Web GIS app that presents the spatial patterns of US population growth, explore the reasons behind the patterns, and share what you found with the public using Story Maps. In the process, you will learn the skills to create a feature layer using geocoding, style your layer using smart mapping, configure layer pop-ups using Arcade, and create a Story Map Journal web app.
Data: For the operational layers, you are provided with a CSV file, C:\EsriPress\GTKWebGIS\Chapter2\Top_50_US_Cities.csv, which contains the 2010 to 2016 population and housing information of the 50 most-populated cities in the US.
There are no latitude and longitude fields in the CSV.
Other operational layers are not provided. You will find them in the Living Atlas.
Requirements:
Your map symbols should be easy to understand.
If a city or region is clicked, your app should display associated details in intuitive ways.
Your app should present the population change patterns and the reasons behind the patterns in story maps format.
System requirements:
An ArcGIS Online or Portal for ArcGIS publisher account. You can use the trial account you created in chapter 1.
A web browser.
Microsoft Excel or a text editor.2.1 Create a feature layer using geocoding
In this section, you will create a hosted feature layer, which will be your main operational layer.
1 In Microsoft Excel, navigate to C:\EsriPress\GTKWebGIS\Chapter2\Top_50_US_Cities.csv, and study the data fields. Note: There are no latitude and longitude fields in the CSV file. The file contains the following fields:Rank: A city’s 2016 rank by population.City: City name.State: Name of the state in which the city resides.Census2010: City population as of April 1, 2010.Estimate2010, Estimate2011, Estimate2012, Estimate2013, Estimate2014, Estimate2015, Estimate2016: Estimated population as of July 1 in 2010, 2011, 2012, 2013, 2014, 2015, and 2016.OccHouseUnit: Occupied house units in 2010.OwnerOcc: Owner-occupied house units in 2010.PopOwnOcc: Population in owner-occupied house units in 2010.SizeOwnOcc: Average house size of owner-occupied house units in 2010.RenterOcc: Renter-occupied house units in 2010.PopRentOcc: Population in renter-occupied house units in 2010.SizeRentOcc: Average house size of renter-occupied house units in 2010.Wikipedia_URL: URL to the city’s Wikipedia page.Picture_URL: URL to the image of the city’s seal or flag.
2 Open a web browser, navigate to ArcGIS Online (http://www.arcgis.com) or your Portal for ArcGIS, and sign in.
3 Click Content.
4 Click Add Item , and then click From my computer.
5 In the Item from my computer window, perform the following tasks:For File, browse to C:\EsriPress\GTKWebGIS\Chapter2\Top_50_US_Cities.csv, and click it. If you have published a file of the same name to your content before, rename your Top_50_US_Cities.csv file to a unique name, and then select it.For Title, use the default, or specify a new one.For Tags, specify keywords, such as US cities, Population change, GTKWebGIS, and your organization name, as illustrated. Separate the keywords with commas.Make sure the check box next to Publish this file as a hosted layer remains selected.Leave the Address option selected.For Country, select US.Review the field types and location fields, and make corrections if needed.Click Add Item.
This CSV does not have latitude/longitude fields. ArcGIS Online and Portal for ArcGIS will geocode your data. Geocoding converts