Project Summary

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Mobile GIS Application

Implemented a modular, extendable, user-friendly mobile GIS application

Project Problem

The Cook County Assessor’s Office (CCAO) handles the assessment of the County’s 1.8 million parcels in residential, commercial, and industrial properties. As part of the triennial cycle of assessment, approximately one-third of these parcels are visited each year by the CCAO’s field inspectors for purposes of confirming characteristics of the properties and buildings. The CCAO desired to improve upon the former methods of planning inspectors’ daily routes and of parcel review, which involved hardcopy maps and documentation in a manual workflow, by introducing mobile GIS access to data and mapping functionality to support these activities.

Project Solution

Great Arc implemented a modular, extendable, user-friendly mobile GIS application for the Assessor’s Office. This service-based framework dynamically pulls independent application modules across the web for display in a client-based desktop application on tablet PCs. The application includes dynamic form entry, dynamic reporting, routing functionality, and provides resource files such as PDFs and photos that are available off-line when no connection is available in the field. County field inspectors can perform data entry and other required tasks in the field on tablet PCs, which communicate with the County server to automatically download each user’s assigned data and check for new versions of code, ensuring that the user has the current data as well as the most recent modules for field work. Modules include Map, Sketch, Photo, Property Information, and required data entry forms. The modular nature of the application framework allows for scalability and expansion for other County departments and applications. Access to specific application modules are restricted based on user group assignments along with read and write privileges. Based on the status of a job, read and write status is toggled between an administrator reviewing a job and the user who is collecting the field data.



  • ArcGIS Server
  • ArcSDE
  • ArcObjects
  • C#.NET
  • ESRI Flex API