ArcGIS Server Blog

ArcGIS Viewer for Flex Application Builder version 2.5.1 and some recent Adobe white paper resources

sterlingdq — Wed, 29 Feb 2012 20:47:00 GMT

We're pleased to announce the latest release of the ArcGIS Viewer for Flex Application Builder. This is a quick-turnaround maintenance release based on the 2.5 release of the ArcGIS API and Viewer for Flex. Highlights include:

Localization support in nine languages: Brazilian Portuguese, Chinese, English, French, German, Italian, Japanese, Russian, and Spanish. Based on your locale, the application builder and all apps created with it use one of these nine languages. The default is English.
Smart URL form specification for specifying ArcGIS Server REST endpoints. When adding services, you now only need to type in the server name, not the full URL. The application builder also remembers the last 50 URLs you've entered, and contains better error handling and messages in this area.
Warnings for server instances that do not have crossdomain.xml files
Support for Bing Maps and OpenStreetMap as basemap options
Support for using a proxy server. Set up the proxy server URL in the advanced settings, then opt in for specific layers or widget inputs that need the proxy.
Application names and bookmark labels can contain spaces and many other characters (including non-ASCII characters)
Numerous usability enhancements and other bug fixes

Learn more by reading this ArcWatch article: Creating an ArcGIS Viewer for Flex Step by Step

We'd also like to share some very useful white papers recently published by Adobe:

Enjoy!

Contributed by the ArcGIS Viewer for Flex development team

Using ArcGIS Server in Windows Azure

sterlingdq — Thu, 16 Feb 2012 17:37:00 GMT

In today's post, we want to address a recent common question: How do you run ArcGIS Server on the Windows Azure cloud platform? Before we get into the details, we need to mention that Esri has not certified the use of ArcGIS Server on Azure yet. We're working closely with Microsoft in order to leverage Azure the best way possible, but as of today, we feel the conditions are such that we cannot provide a supported solution for running ArcGIS Server on Azure. This is definitely on our road map and you will be the first to know, through this blog, when full support is provided.

In the meantime, we thought some of you would be interested in notes we gathered when trying out ArcGIS Server and VM Roles in the Azure cloud.

What is Azure and how do you get ArcGIS Server to run on it?

Windows Azure is Microsoft's cloud platform, currently targeted toward its developer community. Using Microsoft Visual Studio and the APIs exposed by Azure, you can build web applications that take advantage of the Azure cloud capabilities…and ArcGIS Server running thereon.

To run ArcGIS Server on the Windows Azure cloud, you first set up a Hyper-V virtual machine (VM) running ArcGIS Server, using the Windows 2008 R2 Hyper-V role. You then upload the VM to Azure using the Azure SDK tools.

Preparing and Uploading an Azure Virtual Machine Role

A step-by-step exercise on MSDN explains how you create and deploy a Virtual Machine Role in Windows Azure. You can follow the steps in this exercise to deploy ArcGIS Server on Windows Azure, noting the additional items below.

Before you begin the steps in the above article, you need to create an account for the Windows Azure platform and link it to a Windows Live ID. This gives you access to Windows Azure Virtual Machine Roles, required for running ArcGIS Server on Azure. The article infers that VM roles are a beta feature, but this is outdated: VM roles are now a released feature.
When following the steps in the above article, there's a critical time when ArcGIS Server needs to be installed. Before installing the Azure VM role integration components in 'Task 3', you need to install ArcGIS Desktop and ArcGIS Server. Don't run the ArcGIS Server post installs or license the products at this time, though. You'll need to complete the post installs and licensing later, once the machine is deployed on Windows Azure.
In the beginning steps of Task 5, we've seen occasions where the VM role isn't acknowledged from the Visual Studio project. If this is the case, make sure you're using the latest Azure SDK and follow the instructions from Microsoft to enable this functionality. If the VM role option still doesn't show up in Visual Studio, follow the links below to update the registry of the machine hosting your instance of Visual Studio.

Click here for 32 bit

Click here for 64 bit

Your registry will be updated with the needed change.
As you're configuring the VM role in Visual Studio in Step 9 of Task 5, take a moment to consider if you plan to install ArcGIS Server using the default port 80, or a different port. If you deploy ArcGIS Server using a non-default port, then you'll also have to open that port during this step. After you've deployed the VM to Windows Azure, you should also open Windows Firewall to incoming connections on this port.

Once the Hyper-V VM has been uploaded and deployed to a staging or production instance, you can log in through remote desktop to configure your GIS content and applications and publish services.

Note that the instructions in the above article are appropriate for getting ArcGIS Server running as a single machine deployment only. You can scale up your deployment by increasing the size of the VM from the "small" role used in the above instructions. See this page on How to Configure Virtual Machine Sizes. You can also modify the size of the VM after it's been loaded, using the Windows Azure Management Portal.

Data Strategy

There are two approaches you can use for handling file-based data such as file geodatabases. Both approaches rely on persistence of the data, so files are not erased as the VM is started or stopped.

The first approach is to include the data on the C: drive of the same VM where ArcGIS Server is installed. This is a valid option if your datasets aren't very large. The VM C: drive can't be larger than 30 GB, which includes the operating system and all the software already installed. So that doesn't leave a lot of space for big datasets.

Since data can change with different VMs, a good plan is to upload a VM as a base image with only ArcGIS Server and ArcGIS Desktop, along with any other software that might be needed. Then, add your data as part of a different VM (derived from the base image) that you upload on top of the base image every time you have a new or updated dataset to publish. Steps for making VM updates in this way are available here.

A note about the approach above: As you create VMs and run new instances based on them, ArcGIS Server will require you to run the post-install in order to get the new IP and hostname.

If you're going to use a large dataset with ArcGIS Server, it's recommended that you take the second approach, which is to mount an Azure storage drive. For more information about this approach, here's a link to get started on Using the Windows Azure Storage Services.

Supportability note

As we mentioned at the beginning, Windows Azure isn't yet certified as a platform for ArcGIS Server, and Esri Support Services can't help you with the process of launching ArcGIS Server on Azure. For assistance with uploading the VM Role using the Windows Azure SDK or Tools, you should take a look at the Microsoft page Support options for Windows Azure.

Contributed by Marwa Mabrouk of the Esri Product Management team

ArcGIS API for JavaScript version 2.7 released

sterlingdq — Mon, 13 Feb 2012 20:57:00 GMT

Version 2.7 of the ArcGIS API for JavaScript is now available! Highlights include:

Superpan map navigation is now the default when using an Apple trackpad or magic mouse. More information is available in the Map Navigation conceptual help topic.
Feature layers in on-demand mode now automatically generalize features when map scale changes. Refer to the Feature Layer best practices conceptual help topic, specifically the Feature Generalization section, for a detailed explanation.
Some more ArcGIS Server 10.1 features have been added in this release for those testing the beta software:
- Dynamic layers now allow client applications to specify new renderers for data drawn by the server, add datasets to the map, work with tasks (find, identify, query, and generate renderer), and join data from other resources published with ArcGIS Server.
- The ArcGIS API for JavaScript's various layers (dynamic map services and feature layers) as well as tasks (find, identify, query and generate renderer) can now be set to refer to a specific geodatabase version.
- The geometry service can now perform geodesic buffering.
Additions to the conceptual documentation and several new samples. See What’s New in 2.7 for a complete list.

Contributed by Derek Swingley of the ArcGIS API for JavaScript development team.

Esri picture marker symbol generator for JavaScript developers

sterlingdq — Fri, 03 Feb 2012 18:01:00 GMT

The ArcGIS.com map viewer provides a nice collection of picture marker symbols that can be used to symbolize features on your map. If you're a developer, you might wonder how you can use these symbols in your applications. You could potentially use tools like Firebug or Chrome Developer tools to inspect ArcGIS.com and discover the image URL, but to make things easier, we've created a sample that allows you to select a symbol and generate the JavaScript Object Notation (JSON) needed to draw the symbol:

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

ArcGIS Viewer for Silverlight 1.0 and ArcGIS for SharePoint 2.1 released

sterlingdq — Wed, 18 Jan 2012 23:15:00 GMT

The ArcGIS Viewer for Silverlight 1.0 was officially released today for public download. The viewer, which has been in beta for a while, has generated buzz for its ability to easily create a Silverlight-based web mapping application through an intuitive WYSIWYG 'Application Builder'.

A new release of ArcGIS for SharePoint, version 2.1, is also now available. This allows you to incorporate your GIS web services into SharePoint through a Map Web Part. You can also visualize your SharePoint data using a geocoding workflow.

More information about both products is available on the ArcGIS API for Silverlight team blog.

Taking ArcGIS Viewer for Flex customization to the next level: Go Electric

sterlingdq — Wed, 11 Jan 2012 18:57:00 GMT

I created an application to demonstrate how easily a Flex programmer could customize and extend the ArcGIS Viewer for Flex. We can leave the artsy design up to a graphic designer to create Flex skins. After integrating the design into the viewer, we can then concentrate the majority of our effort on tools and workflows that are critical to our business.

"Go Electric" is an enterprise application that allows Go Electric management to view their current electric car charging stations, and evaluate the market potential for new charging station locations. Go Electric is a fictitious company used to model a realistic scenario.

From the image above, you'll notice that this Go Electric example includes some intriguing customizations:

A customized menu bar and widget buttons
A new template for widget windows
A custom overview widget
A new basemap picker control
A market potential widget that uses the ArcGIS Business Analyst Online API for demographic analysis

To download the source code and read technical details about how I made this app, click here.

Contributed by Julie Powell of Esri Professional Services.

Enhanced map navigation for Mac OS X using the ArcGIS API for JavaScript

Kelly — Fri, 06 Jan 2012 18:13:00 GMT

With the release of OS 10.6 Snow Leopard and Lion OS, the Mac Magic Trackpad and Magic Mouse allow you to interact with the system using touch gestures like tap, scroll and swipe. While not all gestures are passed on as native browser events, some gestures emit traditional browser scroll events that enable intuitive and powerful map exploration.

If you have a Mac with OS X 10.6 or greater, click here to view a demo that shows how to pan and zoom using the track pad gestures. The default behavior is pan, press the shift key to enter zoom mode.

We plan to make this the default user experience for any Mac with OS X 10.6 or greater at the next release of the ArcGIS API for JavaScript (2.7) so we'd love to hear your thoughts on the functionality now.

Users experienced at working with touch screen devices like iPad and iPhone may wonder why they can't use the pinch gesture to zoom. Desktop browsers currently do not provide access to these events. Hopefully this will change in the future and we'll be able to upgrade to add this functionality.

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

Hardware accelerated map navigation with CSS3

Kelly — Thu, 15 Dec 2011 20:30:00 GMT

One of the enhancements to the ArcGIS API for JavaScript at version 2.6 is the use of CSS3 transforms while panning and zooming a map. When enabled, there is a subtle animation and fade when images that make up tiled map layers are added to or removed from the map. You can see this in one of the simple SDK samples. This is similar to how the other ArcGIS web APIs, for Flex and Silverlight, operate.

There are both aesthetic and performance benefits from using the latest and greatest in CSS. Aesthetically, the transition between map levels is more pleasing due to a fade animation. For performance, some webkit and mobile browsers use hardware acceleration when a webpage uses CSS transforms. This is especially beneficial on older versions of iOS.

Like other new HTML5 and CSS3 capabilities, transforms are not yet consistently implemented across browsers. For a complete rundown of browser support, check out caniuse.com's browser support chart for CSS3 transforms. While that's a good reference, there are some subtleties to the current implementations. In Chrome on XP, there's an existing bug that will hopefully be addressed by Chrome 17 in early 2012. For Firefox, version 10 (also due in early 2012) should bring full support for transforms.

Version 2.6 of the ArcGIS API for JavaScript uses CSS3 transforms by default where they're supported. The API will automatically use CSS3 transforms for the following browsers:

Firefox 4+
Chrome 4+
Safari 3.1+
IE10
iOS (mobile Safari) 3.2+
Android 3+

The API uses "classic" mode (no transforms) for Internet Explorer 6, 7, 8 and 9.

In the rare case where a developer would like to opt out of using transforms, we provide map configuration options to disable transforms. Please refer to the options section of the map class documentation, specifically the navigationMode property.

Contributed by Derek Swingley of the ArcGIS API for JavaScript development team

Version 2.6 of the ArcGIS API for JavaScript released today

sterlingdq — Wed, 14 Dec 2011 17:00:00 GMT

Version 2.6 of the ArcGIS API for JavaScript is now available! Highlights include:

Improved map display using HTML5 and CSS3

When supported by the browser, the API now uses CSS3 transforms to provide a smoother zooming and panning experience.

Support for the latest version of maps from ArcGIS Online

ArcGIS Online web maps with layers created from remotely hosted comma-separated values (CSV) files are supported. This includes fusion tables and CSV files hosted on the open web.

Enhancements to the Basemap Gallery widget

The Basemap Gallery now supports working with a group of maps within ArcGIS Online. To use a group, specify the basemapsGroup constructor parameter when creating a Basemap Gallery widget.

Support for new features in ArcGIS Server 10.1 beta 2

New features now supported by the ArcGIS API for JavaScript but that require a 10.1 service:

Enhanced query capabilities that support order by and group by queries
New GenerateRenderer task to automate the process of generating a renderer from data in a map service. The task can be used to generate class breaks, color ramps, and unique value renderers.

New printing capabilities via a print task and print widget.

Additional API Enhancements and Bug Fixes

Please refer to the What's New in Version 2.6 topic in the documentation for additional information about version 2.6 of the ArcGIS API for JavaScript.

Contributed by Derek Swingley of the ArcGIS API for JavaScript development team

ArcGIS API and Viewer for Flex 2.5 now available

sterlingdq — Mon, 05 Dec 2011 22:15:00 GMT

The ArcGIS API for Flex enables you to build dynamic rich Internet applications (RIAs) for ArcGIS Server. The new 2.5 release includes support for WMTS layers, enhanced support for KML, and an improved editing user experience. It also supports cloud-based services hosted on ArcGIS Online (available for those who are beta testing the 10.1 subscription program for ArcGIS Online). Finally, the 2.5 release incorporates bug fixes and enhanced support for ArcGIS.com web maps.

The updated API is available for download from the ArcGIS API for Flex Resource Center.

Coinciding with the release of the API, the ArcGIS Viewer for Flex 2.5 is offered under the Apache 2.0 License, includes a new chart widget, and has its source code available on GitHub. This significant release includes a new experience for configuring the Viewer using an application builder, enabling new users to easily configure and deploy a new application without programming or editing an XML configuration file.

The updated Viewer is available for download from the ArcGIS Viewer for Flex Resource Center.

Using the new ArcGIS Viewer for Flex 2.5, you can use its application builder to interactively select web maps from ArcGIS Online as the data source for a new web application.

To add and configure widgets for the Viewer, just point and click.

The application builder contains an interactive WYSIWYG preview that you can use to see your map.

We hope you enjoy working with the latest release.

Contributed by the ArcGIS API for Flex development team

Some thoughts on the direction of the ArcGIS web mapping APIs (JavaScript, Flex, and Silverlight)

sterlingdq — Thu, 17 Nov 2011 18:39:00 GMT

With Adobe's announcement of discontinuing support for Flash on mobile device browsers, industry rumors on the lifespan of Silverlight, and the growing future of HTML5, many users have asked for Esri's perspective on this news.

Esri continues to fully support four distinct patterns of application development:

JavaScript / HTML5
Silverlight
Flex
Native device applications

We’re committed to providing the best technology for GIS developers and giving choices from the most widely used developer platforms in the market. By offering many options, we enable developers to address different customer needs and expectations. Our commitment is not based on a specific technology, but based on supporting the GIS developer regardless of the platform chosen. Each of these areas: JavaScript/HTML 5, Flex, Silverlight, and native application code, gain significant improvements in the upcoming ArcGIS 10.1 release.

We have been supporting HTML5 developers through the ArcGIS API for JavaScript for some time. HTML5 is leveraged internally by the API when supported by the browser. The ArcGIS API for JavaScript documentation includes a broad variety of developer examples using HTML5. Our agenda for supporting HTML5 developers will continue to be aggressive.

Adobe recently announced the discontinuation of support for Flash Player in mobile device browsers, however there is continuing commitment and development for Flash Player for browsers on desktops. In addition, Adobe is directing mobile developers to write native applications using authoring tools such as Flash Builder and AIR, and replace Flash-based web mobile browser applications with HTML5-based applications. Adobe is evolving its developer offerings to match this vision, and Esri’s ArcGIS API for Flex will continue to closely match them with upcoming releases. Outside the mobile space, Adobe continues playing a major role. We’re committed to supporting Flash/Flex for the foreseeable future as many of our customers have successful deployments using it.

EDIT: Adobe has released more information to clarify their recent announcement:

Some have asked about Silverlight support as well, given the various industry rumors on its lifespan. We work closely with Microsoft and will continue to support and advance this platform as demanded by our users. Several product updates and new releases based on Silverlight are scheduled for the upcoming months, including our ArcGIS API for Silverlight, ArcGIS Viewer for Silverlight, ArcGIS for Windows Phone, and ArcGIS for SharePoint. We’re committed to providing the Microsoft developer with the best GIS tools, and our offerings will closely match the latest trends promoted by Microsoft.

In addition, we are aggressively adding to our native application support by providing the new ArcGIS Runtime on multiple platforms. This technology will enable developers to leverage the native capabilities of various platforms and devices, and is supported across desktops (Windows and Linux), and mobile and tablet devices (Android, iOS, Windows Phone, and Windows Mobile).

Esri has always focused on computing and development platforms that are viable and demanded by our customers, and that focus has not changed. We have strong strategic alliances with organizations like Microsoft, Adobe, W3C, and others to ensure we are technically aligned and participating in the future directions of technology. This keeps our GIS offerings relevant in the fast-paced world of platforms, devices, and technologies.

Contributed by the Esri Product Management team

Crafting your own basemap styles with Flex or Silverlight

sterlingdq — Mon, 14 Nov 2011 21:13:00 GMT

When building web mapping applications, choosing the right basemap is not always an easy task. I always look for basemaps that will make my data stand out. I do not want the basemap to be a distraction. I also ask that the basemaps provide good context: maps with rich background information, generally in the form of roads, place names etc.

Sometimes, there seems to be no good choice. The very rich basemap takes away attention from my data, and the basemap that sits quietly in the background does it at the expense of being too sparse.

At the heart of this dilemma is the fact that there is not just one good basemap that fits all situations. It all depends on how rich your operational data is, what type of symbols you use to represent it, what background information is enough for your specific app, etc

While ArcGIS Online provides you with quite a variety of basemaps, in this post we are going to explore a handy technique for giving a final touch to those basemaps. A technique that may actually achieve the balance you were looking for, without requiring you to make any new maps from scratch. Using logic available in Flex and Silverlight, we will apply a client-side color remapping to the map tiles. This makes it possible to apply a great number of styles to existing basemaps without creating new tile caches.

It is probably best to look at same examples to see what I mean. First, let’s have a look at San Diego through the lens of the "Streets" basemap from ArcGIS Online:

Now, let’s apply a light gray-scale tint to it:

And a darker one:

Here is my midnight-blue version:

Well, that may be too psychedelic for some, although the same effect applied to the "Terrain with Labels" basemap over Florida gives an interesting look:

Just like there is not a basemap that fits all, no one filter will give a magical touch. So the key is to learn enough about how to do this so you can create your own filters. There are quite a few articles out there describing the science behind this trick. Paul Haeberli explains it quite succinctly. But to make things simpler, we have created a couple of apps that will let you interactively create filters for your basemaps. These apps will help you incorporate this technique into your own projects. Play with the live apps, download the source code and enjoy:

Effects and filters with the ArcGIS API for Flex

Effects and filters with the ArcGIS API for Microsoft Silverlight

Have fun.

Contributed by Ismael Chivite of the ArcGIS Server product management team. Idea originally sparked from looking at Toby Segaran’s Walmart Growth video. Sample apps and source code written by the Esri Applications Prototype Lab. Also thanks to Antony Jayaprakash and Mansour Raad.

Boosting performance through pre-computing

sterlingdq — Thu, 20 Oct 2011 16:34:00 GMT

At Esri conferences, we frequently offer workshops on designing faster GIS web services. Perhaps the most important piece of advice that we give in these workshops is to pre-compute when possible. In this post, we’ll explain what we mean by “pre-computing” and offer some simple ways you can speed up your ArcGIS Server services by following this principle.

The importance of pre-computing in a server environment

When you do something in your desktop GIS program, you have the computer all to yourself. You can ask the computer to do computationally-intensive things, and often those things will be accomplished fairly quickly because you have the machine’s entire resources at your disposal.

In the server GIS world, things are a bit different. You usually aren’t the only one requesting things from a GIS server. It may have thousands of other users to accommodate at the same time. And in the web world, most users expect to see their results immediately. If a user has to wait longer than a few seconds for something to happen, the app may be deemed unusable, no matter how amazing its functionality.

The key to pre-computing is to understand what work your server is doing, and complete as much of that work as possible before the user request is made. The less work your server has to do at the time of a user request, the more users it can accommodate at once. Let’s look at some examples.

Map caching

Map caching is a prime example of pre-computing in order to keep your services running fast. You spend some initial time and computing resources drawing map images (tiles) and storing them in a server-side cache. After the cache is built, the service can just hand out the tiles as requested instead of drawing map images on the fly. Usually the tiles are created on a staging server and copied onto the production server during off-hours. Not only is map caching fast (a server can return a tile in a fraction of a second), it’s also scalable. You can accommodate many more simultaneous users when handing out cache tiles because your server is hardly doing any work.

It can take a long time to create a map cache, especially if the map covers large scales across a broad geographic extent. Fortunately many of the other pre-computing tips in this post can help speed up tile creation.

Projecting data

Projection on the fly is computationally intensive, and it can introduce itself at various tiers in your GIS server architecture. If you can match the coordinate system of your source data, your data frame, and your web map, you can eliminate projection on the fly altogether.

Most people hesitate to match their coordinate system all the way up the stack because their web maps use Web Mercator, an undesirable projection for storing source data. A solution to this is to make a one-way replica of your datasets in Web Mercator to use for web drawing purposes only. The replication action can actually output the data to Web Mercator, which is an easy way to project all your datasets while leaving the parent replica in the original coordinate system.

See Esri Knowledge Base article 34129 to learn more about changing coordinate systems during replication.

Pre-calculating geoprocessing results

If your app contains a geoprocessing model that could be run on a common or known set of features, consider pre-calculating the results and storing them in a database or table. In our workshops, a common example we show is the Solar Boston app, in which the developers pre-calculated the solar potential of all the rooftops in downtown Boston. You can click any rooftop in this app and see the solar potential in a fraction of a second, because the model result is already stored as an attribute of the building. On the other hand, if you use the option to calculate the solar potential of a freehand polygon, you have to wait a while for the server to run the model.

Maintaining spatial and attribute indexes

When ArcGIS draws a map, it has to retrieve all the features that pertain to the current extent of the map. If the datasets in the map have a spatial index built, the features can be found much more quickly, and therefore the draw speed improves. Build spatial indexes and keep them up to date for any datasets whose drawing performance is a concern.

Similarly, when ArcGIS performs a query on a table, an attribute index can help it find the needed records more quickly. If you know that a certain field will be queried often, it’s worth the time to create an attribute index for that field.

Labeling with annotation

Automatically finding an ideal placement for map labels is a computationally intensive problem that has inspired much research. Modern label engines such as Maplex are able to position scores of labels in a tiny map space without overlap. However, these intelligent label placement decisions cost CPU and memory resources. Your server can be spared some labeling work on each map draw request if you use annotation.

Annotation is a technique for saving label information to a database. When you use annotation in your services, each label has a predetermined location; therefore, the server doesn’t have to make any label placement decisions. To get the best of both worlds, you can use Maplex in ArcGIS Desktop to get the best possible placement for your labels, then save those labels to annotation for use in your web services.

Summary

The above examples show that there are a variety of ways that you can pre-compute information to speed up your GIS web services. Many of the pre-computing techniques can also help speed up the creation of map cache tiles, which is the ultimate form of pre-computing.

Do you have any other pre-computing practices that you use to speed up your GIS? We’d like to hear about them as comments to this post.

Contributed by Sterling Quinn of the ArcGIS Server development team

ArcGIS API for JavaScript - Basic Viewer template now available

Kelly — Tue, 11 Oct 2011 17:15:00 GMT

We recently added a new JavaScript application template to ArcGIS.com called the Basic Viewer. Using ArcGIS.com and the Basic Viewer template, you can quickly create and publish applications with commonly requested functionality such as a legend, basemap gallery and print tools. The template includes many out-of-the-box widgets from the ArcGIS API for JavaScript including the Editor, TimeSlider and Measurement widgets. The Basic Viewer template is a fully configurable application that you can configure in ArcGIS.com or via a configuration file if you choose to download the template and host it on your web server.

How to make a web application with the Basic Viewer

Create a Web application based on the Basic Viewer template by performing the following steps:

Open an existing map (or create a new one) using the ArcGIS.com map viewer. Use the map viewer to add layers, set an extent, configure map popups and add map notes. All of these settings are honored by the template and will appear in the application built using the template.
Click the Share button and choose who can view the map. To publish the map as an application, you need to make the map available to a group, your organization, or the public.
Click the Make a Web Application option to display a gallery of templates.
Select Basic Viewer and use the Preview option to view your web map in the Basic Viewer template. The preview option is a great way to determine which template works best for your map.
Close the preview window and select the Publish option for the Basic Viewer template to create a custom application based on the template. This published application is added to ArcGIS.com and can be shared with the public or with users in your group or organization.

If you would rather host the application on your own web server, you can select the download option and download a zip file containing the full source code for the template. The zip file contains instructions for installing and configuring the template.

Configure the published template

After publishing the web map as an application, use the Configure App option to modify the application’s tools, title and color scheme.

The last step of the application publishing process displays a dialog with details about the newly published application, and includes a link so you can view the item. Click go to the item now to edit the application’s description, thumbnail image, tags, and to begin the configuration process. You can always access the application via the My Content tab.
Click the Configure App button to display the application configuration page. This page displays a preview of your web map using the Basic Viewer template along with options that allow you to change the appearance of the application and specify the functionality you want to include.
After making the changes, click Refresh to view the template with your new settings and click Save to apply the changes to your application. Note that you can return to the configuration panel at any time and modify the template.

Click here to view an application created using the Basic Viewer template. We hope you enjoy using the new template and are excited to see applications you build!

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

Cross Origin Resource Sharing (CORS) with the ArcGIS API for JavaScript

Kelly — Thu, 29 Sep 2011 19:57:00 GMT

Version 2.5 of the ArcGIS API for JavaScript introduced support for cross-origin resource sharing (CORS). CORS allows web applications to bypass a browser's same origin policy and access resources or services on other servers/domains. CORS is supported in modern, non-IE browsers and is usually classified as a component of HTML5.

When both the web server and browser support CORS, a proxy is not required to do cross-domain requests to get around that same origin policy. CORS both simplifies application development and provides a performance boost. Development is simplified because it is no longer necessary to maintain a proxy page on your server. The performance boost comes from no longer using a proxy page. Instead of a web app sending a request back to its server, waiting for the server to access another resource or service, and then interpreting the result, the app just accesses the resource or service directly. Eliminating the server as a middleman makes apps faster and frees up resources on the app's server.

To use CORS from an ArcGIS API for JavaScript application, add the root URL for CORS enabled servers to esri.config.defaults.io.corsEnabledServers, which is an array of strings. As stated previously, web servers must be pre-configured to support CORS. This is a straightforward, simple process and enable-cors.org has walkthroughs on how to enable CORS for popular web servers.

While additional server side configuration is required to use CORS with a 9.3 or 10.0 ArcGIS Server instance, 10.1 instances of ArcGIS Server will support CORS out of the box.

Within the ArcGIS API for JavaScript, the main use cases for CORS are sending large geometries to a geometry service and doing various editing operations. Both are done with HTTP POSTs, and would otherwise require a proxy page if the ArcGIS Server services being used were not hosted on the same domain as the requesting application.

To test CORS with the ArcGIS API for JavaScript, check out the sample CORS apps in the ArcGIS API for JavaScript documentation. If you're using a browser that supports CORS, you will see cross-domain POST requests when monitoring your HTTP traffic using Firebug, Chrome Dev Tools or some other tool. If you hit the apps with Internet Explorer, you'll see that a proxy is still used. You can also experiment with the ArcGIS Server services running on servicesbeta.esri.com as that server has been configured to support CORS. Enjoy!

Contributed by Derek Swingley of the ArcGIS API for JavaScript development team