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ArcWatch: Your e-Magazine for GIS News, Views, and Insights

March 2008

ArcGIS Image Server Serves Sanborn Well

By Karen Richardson, Esri Writer

Today, imagery is available from many sources, but the steps for managing, processing, and distributing imagery using conventional methods can be time consuming. Because images are a snapshot in time, the faster they are made available, the more useful they become.

A company that understands this concept well is Sanborn, based in Colorado Springs, Colorado. Founded in 1866, Sanborn has grown from publishing fire insurance maps so detailed they are still in use today to creating imagery products for clients across the United States.

Many of the company's imagery projects cover large areas, and clients sometimes require multiple gigabytes of delivered image data. Time is money, and Sanborn needed an innovative solution that would get the images into the hands of its clients quickly.

Sanborn found Esri's ArcGIS Image Server to be the optimal solution. Because ArcGIS Image Server could handle massive amounts of imagery and process images on the fly and on demand, Sanborn chose the software as the basis for its GIS applications and became an Esri implementation partner.

No Preprocessing or Alteration of Source Data Needed

ArcGIS Image Server doesn't require conventional extensive preprocessing or alteration of source data, allowing access to images as soon as they are in the system. "ArcGIS Image Server allows Sanborn to offer our clients a solution that gives them the images they require immediately with consistency," says John Copple, chief executive officer of Sanborn.

Sanborn customers include large counties such as Maricopa County, Arizona; city governments; and statewide initiatives. Delivery size of an imagery project can range from 144 gigabytes for one area to 4.4 terabytes for up to 30 delivery areas, based on an average tile size of 2,000 x 3,000 pixels for a delivery area size of 2,000 tiles, the equivalent of 400 square miles. Sanborn's delivery format is RGB, with a six-inch pixel size. ArcGIS Image Server decreases the latency between image collection and end-user availability.

Traditionally, image processing and distribution were considered two separate stages in image utilization. Imagery was first processed and mosaicked into a large dataset, then put on servers for dissemination. This separation caused many problems—long preprocessing and loading times and data redundancy that exacerbates data storage issues and hinders efficient data management. With ArcGIS Image Server, these two stages are combined into one. The data received from an imagery supplier can be directly served, enabling administrators to maintain only the primary imagery while creating multiple specialized products on the fly when required. This is a significant and unique paradigm shift in how imagery is managed, processed, and distributed.

Using ArcGIS Image Server, Sanborn created a client imagery interface called Sanborn Quality Assurance (QA) that facilitates Web-based quality checking of Sanborn-created orthophoto products. Clients can view imagery through a standard Web browser as the image is being processed and add digital "issue points" to areas within the imagery that they feel may require attention. Clients' ability to do this while Sanborn is processing the imagery simplifies data management, reduces data redundancy, and makes the imagery accessible in less time.

Since the error reporting is in real time, Sanborn and its clients can perform QA reviews online as soon as the data is processed. This is a significant improvement over the time lag experienced with the traditional method of waiting for the orthophotos to be processed and delivered on CD or other storage devices. The online QA tool also reduces quality-check error rates while ensuring customer requirements are met. This, in turn, shortens customer delivery schedules and gives clients the highest-quality imagery possible.

Clients can review orthoimagery as soon as it's finished processing. Users are granted entry to the image Web application via secure login privileges to access a particular project. They may add to the project QA flags that require additional review, and these become immediately available inside the main GIS for viewing by Sanborn's production staff and technicians to review and resolve. These digital issue points give clients the ability to efficiently describe errors and make fast, responsive changes to the imagery such as color balancing and edgematching. There is also a reporting tool that provides up-to-the-minute quality control status of the project. This makes the problem resolution process more streamlined.

All imagery is served from a central image server to the client-side computer within a mapping interface in a standard Web browser format. ArcGIS Server 9.2 authors map documents that contain the image server data and QA/QC feature classes. ArcGIS Server Application Developer Framework (ADF) functionality gives Sanborn the map navigation and feature editing it needs. Edit call type buttons control edit call digitization.

ArcSDE technology provides access to the data including stored QA/QC points. Using this solution, the QA/QC points are instantly ready for status and resolution and updates to the points by the QA team are immediately available online.

ArcGIS Image Server is used for fast access to the extensive imagery using on-the-fly, server-based image processing. Built on fully scalable enterprise client/server architecture, it offers multiplatform GIS/CAD/Web client access and direct access to many file formats and compression. Using the software, multiple imagery projects can be created from a single source.

Clients Just Log In Online

Clients can help manage projects through macro-level access using a login access control with granular security role assignment. A custom ASP.NET application adds robust security. Resource assignments are now very easy and flexible.

This online login system uses a standard Web-based browser to access a project. Once logged in, the QA user will see a list of projects that are accessible. By clicking a link from the Map pull-down menu, the user opens the QA environment for the project. The initial map that is displayed shows the project status through colored pixels, green specifying tiles available for review and red for areas not yet available. The user can then add and view the current issue points for the project. Points are symbolized by status and can be selected to view more details. The system was prototyped with Sanborn customers from Colorado and Texas. Based on positive prototype experience and customer feedback, the company released a next-generation system for use by Maricopa County, Arizona. This county is approximately 9,200 square miles, with an expected data delivery size of around 4.4 terabytes.

Implementing the system took approximately 150 man-hours, from the initial design, including requirements, to purchasing and implementing the software, customization, testing, and final release.

Sanborn QA requires nothing more than a standard Web browser and high-speed Internet connection. After clients utilize the system and are satisfied with the quality of the imagery, the project is delivered either through turnkey ArcGIS Image Server delivery, on-demand data staging for after-flight review (which is available within 24 hours of the request), or traditional hard-drive or DVD delivery.

"The instant online imagery review accelerates our quality assurance and quality control review," says Copple. "We have given our customers the option to completely eliminate physical shipping requirements for QC purposes."

Sanborn also successfully reduced its clients' IT involvement and provided a secure solution for project management. Using this solution, Sanborn clients get fast image access optimized to their requirements with improved image quality and image metadata. By serving data to its clients directly, Sanborn has realized an overall production-to-delivery-time decrease of approximately 66 percent in some cases. Due to the schedule savings and the increased QC accuracy, Sanborn is able to improve its responsiveness while saving customers costly edit and deliverable delays.

"It's now easier for us as a company to assign our resources and offer flexible, efficient delivery options to our clients," says Melinda Brown, vice president of corporate marketing at Sanborn.

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