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Mobile Field Appraiser App

Business case need for a mobile map application for a rural Texas appraisal district: Llano County.

April 2018

Needs assessment

Llano County is rural county located in the Texas Hill Country. The Llano County Central Appraisal Districts (CAD) has the responsibility to access and appraise real properties for the purpose of collecting Texas ad valorem taxes. They currently have a digital map and online map that represent the parcels for the county. BIS Consulting maintains the digital map and hosts that map online through an ArcGIS.
Llano CAD has identified a need for a light-weight Mobile Field Appraisal application that would allow their field appraisers to take appraisal district’s parcel map layer into the field with a current imagery base layer and collect a few attributes. A need for the ability to take photographs of property improvements during the appraisal process was also identified.

Requirements for the mobile device
  • The Mobile Field Appraisal app would allow field appraisers to click on a map, query a parcel ID and setup a drive route to the selected parcel.
  • The app needed to be able to display key attributes that pertain to a parcel that is being appraised.
  • The key attributes that are needed during an appraisal are later updated into Computer-Assisted Mass Appraisal Software (CAMA) database.
  • The app needed to have a base imagery layer with sufficient detail to view and identify structures.
  • The app needed the ability to take the complete map offline and still use it in a remote area where you’re unable to connect to cell service.
  • The mobile app would need to work with your mobile device to collect photos of the properties and easily downloaded from the app with well-organized filenames by parcel ID.
  • A web map was required that can be viewed back at the office. This will be a working map that would show what properties were completed for appraisal with the name or initials of the field appraiser.
  • The CAD required two ArcGIS accounts for field appraisal staff.
  • Minimum security was needed as data is public domain.


Test results

The BIS Mobile Field Appraisal Application has been tested in the field and met all the above requirements.
Two web maps were published; one was dedicated for collecting key attributes and was connected to cell service and the other for offline collection. Both maps are pointing to the hosted feature layer. The purpose being you could use both in your planned day to appraise property in both online and offline mode.
Two iPads were setup with the BIS Mobile Field Appraisal Application. We identified the parcels that would be in an area with no cell service. Using the app, we captured the extent of the area with the parcel layer and imagery. As we planned our day in Llano CAD’s office, we were connected to their Wi-Fi and stored the map offline. A BIS team member traveled along with a Llano CAD appraiser and collected some attributes notes, populated test fields, and took some photos at each site. The information was edited and stored within the app in the areas we previously identified to have no cell service. When we returned to the office, the data collected was synced. We were then able to open the published web maps to view the updates and edits to the Llano CAD working map for field appraisals.

The value for the CAD field appraisers

Llano CAD’s appraisers provided some feedback regarding the app after the test and felt the application has great potential for the appraisal district. Overall, it will significantly assist field appraisers in planning and routing their appraisal work:

  • Collecting important data in the field and having the ability to manage photos.
  • Having all the data fields pertaining to the property during the appraisal was a plus.
  • Assisting new field appraisal staff by just getting maneuvering through the county to all the properties in a timely manner.
  • Being able to track progress during the field appraisal season and having a working map that can be used to find errors in the field that can be documented and sent to BIS for GIS Maintenance updates to the Llano CAD parcel layer.



The BIS Mobile Field Appraisal Application has the potential of being a valuable tool to be used in a critical part of the workflow that a Texas Appraisal District must perform each year.


Thanks to Darren Sullivent, Senior Field Appraiser Llano Central Appraisal District for testing the application in the field and his feedback. BIS is working very diligently to provide this affordable solution to all small- to medium-sized appraisal districts. Please contact us if you wish to be one of the first to use the new product.

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