We tackled this challenge by using  what we call the Aggregated Live Feed methodology. This process downloads data from live sources such as NOAA and the USGS and aggregates it into a geodatabase, which is then served through ArcGIS Server as map services. You can see some of these feeds in action by visiting any of the ‘latest incident maps’ on the Esri Disaster Response site.

Recently we’ve developed a much simpler approach called ALF-Lite that doesn’t require specialized knowledge of the enterprise geodatabase or third-party components. This methodology can be deployed to any large or small environment that supports Esri’s ArcPy site package.

This new approach combines native Python functions to handle operational tasks, ArcPy to handle most GIS functions, and the lightweight file geodatabase to handle data storage.

Visit the Aggregated Live Feed Community for available downloads.

How the methodology works

In the diagram below, you’ll notice that the feed routines start by downloading and preparing the data.

The output workspace is then prepared by performing any feature class management or schema operations required before inserting or updating the new data.

The last operation is to invoke the user-controlled deployment logic, allowing you to deploy the data any way you like by adjusting the configuration file. By default, the routine copies the output file geodatabase to a live folder that can be accessed during the update cycle thanks to the file system copy operations provided by Python.

Keep the live data folder updated automatically by creating a scheduled task to launch the feed routine as necessary. Access the live data directly with ArcGIS Desktop, or publish it using ArcGIS Server!

Contributed by Paul Dodd and Derrick Burke of Esri Technical Marketing

This checklist helps you assess your map as an information product designed for a specific audience.  When do you need to consult this checklist?  Use it any time before you publish your map.

Various staff at Esri developed and honed the checklist over the years as we built and shared maps with our colleagues and customers.  Over time, we noticed which “little things” seemed to help other people find and use these maps effectively.

The goal of this blog is to encourage you to develop and use your own checklist, perhaps using this one as a starting point.  While this version focuses primarily on web maps and map services, additional sections in your checklist could focus on critical things you know to provide when serving image services, feature services, WMS or KML.

People who use this checklist report that it helps them focus on their map as an information product – one that needs to be easy to understand, and well documented.

We all share a common goal: to publish maps that are technically correct, with clear messages both on the map and in the documentation.  A checklist helps ensure that these things are considered.  But it does not turn a bad map into a good one.  There are other blog entries dedicated to map design and the rapidly-evolving web and mobile environments for maps.

Many map publishing projects start with an .MXD, which later is shared as a service.  The checklist is quite useful early in the process, as you settle on what layers to use and how to show them cartographically.

Take the map’s legend, for example.  As you add and symbolize layers in your .MXD, the default layer name, default field name and default class labels that the software suggests are what will appear in the final product.  In ArcMap, look at your table of contents and take the few minutes required to translate file names and jargon into words and numbers that communicate (e.g. see Figure 1 below).

Figure 1: What you see in your MXD’s legend is what appears in your web map. Avoid cryptic file names, field names and legend labels that report numbers but not context. The legend in this example uses qualitative phrasing (e.g. “Great Increase”) as well as numeric (e.g. “More than 1.5%) because the audience likely has no idea what constitutes significant increases or decreases.

Just as the legend is the key to understanding the map visually, documentation about your map is the key to understanding its story.  Over time we have found that good documentation about your map is as important as the cartography and the legend.   Did you know that the information you put into the MXD properties will end up appearing in several other places?  See examples below:

Figure 2: Documentation starts in the MXD and flows to a web map.

As you build your map services, ask yourself: “What would an end user of this map want to know about this map’s subject?”  Document that in a clear, easy to read summary (1-2 sentences) and a description (longer, but not a dissertation).  Build a web map from your service and put it in an application, to see things from another perspective.

For publishing web maps, the checklist emphasizes the essentials.  The map’s title, summary, description, tags, credits and access/use constraints are the main text elements to enter.  Create a thumbnail for your map that is visually appealing and distinct.  Define a compelling popup.

Figure 3: Documentation from a web map flows to applications that use it.

Your map services are also going to be used by application developers.  A good map provides key information to the developer, so that their basic questions are answered: “What is this map? What does it show? What time period does it cover? What is the source of its data?  What rights do I have to access and use this map service?”

Popups are an important way to connect with your audience, and good news – they are easier than ever to configure.  Unfortunately, many people choose the default popup “style,” which is an identify-style table of rows and columns like this:

In  just a few minutes’ time, you can write a more understandable, reader-friendly sentence or two about the data using a simple chart like this:

Notice above how the theme of the map (“Persons without medical insurance”) is also the focus of the popup.  The popup has been transformed from a table of numbers into a readable sentence and chart.  These give additional context by providing state and national figures for comparison.  These figures were added to the source data specifically for this popup’s chart.

Necessary?  Absolutely!  Just because you (or your customer) knows the data and its subject well doesn’t mean your audience will.  The popup above is a simple example of the difference between showing data versus information.

When you have a first draft of your web map or map service ready, review it against your checklist.  Before you show anyone the map, look through the checklist to see which items are essential to address.  After you share your work with a trusted colleague to review and provide feedback, return to the checklist to finish going through the rest of the items.

Using the checklist forces you to consider how well you communicate your map’s message.   Send us feedback on the checklist. What works well? What could be improved upon?

What’s going on with Flex at Esri?

The Flex Team at Esri is growing and doing great. In the last few months we’ve added three new team members. For more information about Flex at Esri and Adobe, please read the following posts.

• Some thoughts on the direction of the ArcGIS web mapping APIs (JavaScript, Flex, and Silverlight) [Esri]
• Adobe’s view of Flex and its commitments to Flex in the future [Adobe]
• Adobe roadmap for the Flash runtimes [Adobe]

Mobile

I’m always surprised by the number of people that don’t know that you can use the Flex SDK and the ArcGIS API for Flex to build mobile applications for Blackberry, Android, and iOS devices.  Several people came by with new iPads and showed us some great Flex apps.  The interest in mobile was more popular than expected at this year’s conference, possibly due to the fact we showcased it in several Technical Workshops. Below is a basic example of the ArcGIS API for Flex running as a native application on an iPad 2.

You can download the Flash Builder Projects used to build this application from ArcGIS.com (2012 Developer Summit ArcGIS for Flex “Sharing code across platforms” Samples). Note: You will still need to download the ArcGIS API for Flex from the Resource Center.

Mobile resources
http://www.adobe.com/devnet-apps/flex/tourdeflex/web/
http://flex.org/flexgame/
http://www.adobe.com/devnet/flex.html
http://www.adobe.com/devnet/air.html

Security

Many developers had questions about how to add security to their applications. For basic lockdown of applications, you can use basic web application security to lock down your directory. If you set up the security on your services, the IdentityManager will prompt as needed. You can also take advantage of ownership-based access control for more granular control when editing data.

What’s coming for ArcGIS API/Viewer 3.0 for Flex?

API

• Requirements: Adobe Flex 4.6 SDK / Flash Player 11.1 / AIR 3.2  (note that the 3.0 prerelease only required Adobe Flex 4.5 SDK / Flash Player 10.2)
• ArcGIS 10.1 functionality: PDF printing, editor tracking, dynamic layers and much more
• Pop-up windows displaying multiple features
• IdentityManager to log in to secure ArcGIS Servers
• Support for ArcGIS Portal API (not in Prerelease)

Viewer

• Application builder to easily create flex viewer applications
• Support for Portal for ArcGIS, ArcGIS Online hosted services, ArcGIS Server secure services and proxy servers
• Improved user experience in the application builder
• Custom widget support in the application builder (not in Prerelease)

New Resource Centers

Be sure to check out the new resource centers for ArcGIS API for Flex and ArcGIS Viewer for Flex, where you can download the 3.0 Prerelease Application Builder/Viewer, API & Samples and get more information on what’s new.

Final Thoughts

Whether you were able to attend the 2012 Esri Developer Summit or not, you can already find plenary and keynote sessions online. Soon slides from the pre-summit seminars, technical sessions, and user presentations will also be available.

–Contributed by Lloyd Heberlie from the ArcGIS for Flex development team

Features

• Portal for ArcGIS API:  An API to build applications that works with content from ArcGIS Online or an ArcGIS Portal
• Support for ArcGIS Server 10.1 editor tracking which enables automatic tracking of which user created a feature, when a feature was created, which user last updated a feature and when a feature was last updated
• Simpler constructor signatures for esri.SpatialReference class
• Feature Layers now fire an onQueryLimitExceeded event when a feature layer is unable to draw all expected features due to maxRecordCount restriction imposed on the server
• The Identity Manager has new methods to serialize its state and re-hydrate later

New Samples

• View web maps from a group on ArcGIS.com using the Portal for ArcGIS API
• Search ArcGIS.com with the Portal for ArcGIS API to display web maps with GPX data
• Add a non-Esri tiled layer with a single line of code
• Print Dijit with a web map from ArcGIS.com (requires 10.1 print task)
• Create Print Dijit templates using esri.request
• Use 960 Grid System to layout an application

Refer to the full What’s New in 2.8 document for the full list of new features and bug fixes.

API enhancements

This API release requires Adobe Flex 4.5 SDK or higher, which in turn requires at least Flash Player 10.2. The API includes more comprehensive support for ArcGIS 10.1 for Server, including:

• More dynamic rendering options
• Better editing support: editor tracking, ownership-based access control, and support for versions
• Support for the PrintTask to generate printable output on the server
• z and m-value support in map and feature services.

For a complete list of API enhancements go here.

Get the 3.0 API Prerelease from here.

Viewer enhancements

On the Viewer side, this release builds on the comprehensive support for ArcGIS 10.1 for Server in the API, such as:

• Improved user experience, including a Print widget, smart URLs when browsing REST endpoints, and editing capabilities
• Support for Portal for ArcGIS
• Support for ArcGIS Online hosted services
• Support for proxy servers
• Enhanced localization capabilities
• Bug fixes
• Support for accessing secure services

For a complete list of Viewer enhancements go here.

Get the 3.0 Viewer Prerelease from here.

Enjoy, and we’ll see you at Dev Summit!

Contributed by the ArcGIS Viewer for Flex development team

This year’s Dev Summit will introduce ArcGIS 10.1, which is just weeks away from completion. We’ll be demonstrating how you can administer your 10.1 server purely with web services, more easily launch elastic deployments, publish services to ArcGIS Online, view real-time progress reports as map caches are building, and more.

You can search the online agenda by track if you want to see all the sessions on a particular topic, or you can search by name if you’re looking for a particular Esri staff member. You’ll find many contributors to this blog at the Dev Summit answering questions and presenting workshops. Ask any staff member at the Esri showcase your question, and he or she will attempt to direct you to the software engineers or tech sessions where you are most likely to get the best answer. The “Meet the Teams” event on Tuesday evening also offers an informal opportunity to mingle with Esri staff and other attendees.

We look forward to meeting you in Palm Springs!

The seminar included three question and answer sessions. We thought it would be worthwhile to post the five most frequently asked questions along with answers.

1. What is the best way to learn HTML5?

Learn by doing. Dive in (pun intended) and start building sites that use HTML5 features. Start using the new doctype. Use semantic tags. Experiment with things like session storage and the file API. When you get stuck or have questions, reference the any number of great HTML5-centric sites like HTML5 ROCKS and HTML5 Please. Watching the seminar video linked above is also a good start.

2. Is Esri developing a JavaScript viewer similar to the Flex and Silverlight viewers?

No, Esri is not building a stand-alone JavaScript viewer or application builder.  However, we recommend using the ArcGIS.com map viewer and downloadable templates. Esri does offer a template named Basic Viewer that provides commonly-requested web app functionality but it is designed specifically for use with ArcGIS.com and not meant to be a standalone JavaScript API framework.

3. Is feature x supported in browser y?

The best place to find information for feature support by the various browsers is caniuse.com.

4. Has Esri published any application templates built using the ArcGIS API for JavaScript that are tailored to mobile devices?

We have not published any mobile specific application templates but the ArcGIS API for JavaScript documentation includes several mobile-specific samples.

5. How can I get automatic code completion when working with the ArcGIS API for JavaScript?

We have published a code assist plug-in for Aptana 2 but have not updated it for Aptana 3. With Aptana 3, the plug-in format changed and we have not yet been successful in updating to the version 3 format. We are looking into publishing a vsdoc for the API that could be used with Visual Studio (and potentially Aptana).

If you had any other lessons learned, thoughts, or resources you want to share, please post a comment.

Contributed by Andy Gup who is a technical lead with the Esri Developer Network and Derek Swingley of the ArcGIS API for JavaScript team.

When using this sample, just click a symbol and copy the JSON. Then, in your JavaScript code, create a new PictureMarkerSymbol and paste the JSON in the constructor.

var infoSymbol = new esri.symbol.PictureMarkerSymbol({
"angle": 0,
"xoffset": 0,
"yoffset": 12,
"type": "esriPMS",
"url": "http://static.arcgis.com/images/Symbols/Basic/YellowStickpin.png",
"contentType": "image/png",
"width": 24,
"height": 24
});

The application provides two options for generating the image: You can reference the image directly through a URL, or you can embed a string representation of the image (Base64 option in the sample app includes this information). When using the latter option, the image is stored within the document instead of as an external resource, so no HTTP requests need to be made to display the image.

Some browsers, notably Internet Explorer prior to version 8, do not support using Base64 data URIs. In these cases, the image URL is used instead.The snippets from the utility above always include a URL in case one is needed.

Contributed by Kelly Hutchins of the ArcGIS API for JavaScript development team

1. Add an image service into ArcMap.
2. Make selection either by creating a query (Select By Attributes), or by using the selection tool (Select By Rectangle).
   
   
3. In the Table of Contents, right-click on your image service layer, point to Data, and then click on Download Selected Rasters.
   
   
4. Check all the files you want to download.  Here you can uncheck any overviews or other rasters that may have been selected that you do not wish to download.
   
   
5. Optionally, you can choose to clip your rasters to the data frame extent or to a graphic.
6. Click Download.  Your files will be located in the target location that was specified in the Download Selected Rasters window.

The “Maximum number of items downloadable per request” parameter limits the number of rasters that a user can download for each request.  This means that a user can download 20 rasters (20 is the default value) at a time, and then they can make another request to download another 20.  Obviously this can become tedious if you have thousands of images.  If you do not mind users from downloading more than 20 rasters per request, then you can set the number to a higher value.

How do I set the maximum number per download to a higher number?

The number of rasters that can be downloaded per request on the server cannot exceed the maximum number that has been set on the source mosaic dataset (which is 20 by default).  Therefore you will first have to edit the properties on the mosaic dataset itself.  Then you can set the server limit.

1. Right-click on the mosaic dataset, and click Properties
2. Click on the Defaults tab
3. Scroll to the bottom, and look for the Maximum Number of Items Downloadable per Request
4. Edit the value in the “Maximum number of items downloadable per request” to the desired maximum value
5. Click OK

Now the maximum number has been raised on the mosaic dataset itself.  You can now edit the maximum value within the image service, as described in part 1 of this blog.