Who Are We?
Hollister-Powell & Associates is a full service provider, offering services ranging from high-quality computerized mapping, demographics, data exchange, programming solutions, to full on-site computerized GIS automation solutions.

We specialize in customized boundary creation, demographic and client statistical data capture within boundary aggregates, processing and filtering client data and information, standard and customized mapping products, customized digitizing and scanning, and customized programming development.

Geographic Data
The initial design of our geographic database began in 1977. It is one of the most comprehensive and mature systems of its kind in the United States. Through daily client usage, and internal development and enhancements over the past fifteen (15) years, it now encompasses a wealth of intrinsic data layers, and is the most heavily used GIS system in Riverside County. A small sampling of existing layers includes: census tracts, blocks and related aggregates; Riverside County school districts, elementary, middle and high school attendance boundaries; growth monitoring areas; school district study areas; sphere of influence zones; zip codes; assembly, congressional, senatorial, and supervisorial and other political jurisdictions; sheriff districts and sub-stations, and many more.

We have comprehensive sub-layers that include bit-mapped image registration data (aerial photography), contour data (elevations), and point reference data (site locations). All data layers can be super-imposed enabling us to construct an impressive mosaic of vector-on raster-on-point data types. These constructs allow us to produce a map of an aerial photo in a specific area, with street center lines, and a corresponding symbol each school sites in the area. These fundamental relationships allow us to tailor end-products to meet the specific needs of our clients.

We utilize legal documents in the development of our information base from such agencies as: U.S.G.S., U.S. Census Bureau, Riverside County Assessor, Survey, Flood Control, Transportation Land Management Agency, and various other federal, state, county and city agencies. On-going verification of data is ensured through reports, plots, quality inspections, field verifications, usage and queries.

Geocoding Ability
We have the ability to custom address-match any client data file, and apply spatial attributes from our geographic database. Although we are typically used in the GIS community for our address-based layer, we are fully capable of integrating and processing Assessor parcel-based information into our geographic base. We have the ability to assign a parcel identification number to the corresponding street segment, and can isolate the number of parcels and usage code within a given polygon boundary.

Our development environment consists of an Oracle geographic database, with expansion to other platforms such as SQL-Server currently underway. Both our existing system, as well as our newer systems, will remain compatible with any SQL compliant query languages. We utilize both Unix and Windows-NT operating systems. Our in-house interfaces include Visual Basic, Access, Oracle-Forms, and C. We utilize most PC-based GIS packages, with an in-house preference for Atlas-GIS, MapInfo,

Maptitude, GIS+, TransCAD, and AutoCAD. We can and have exported/imported all commonly used GIS formats, including ARC-INFOS and ArcView. We are accessible on the Internet via the County of Riverside Network (CorNET).