Framing the Land
June 17, 2008
Managing survey and land records information is a challenge faced by jurisdictions everywhere. Together, the Bureau of Land Management (BLM) and the United States Forest Service (USFS) manage approximately 461 million acres of public lands. An additional 700 million acres of subsurface mineral resources are managed by the BLM. In an era of smaller budgets, increasing workloads and aging workforces, these demands are an ominous task for any organization.
To meet this challenge, in 1999, the BLM and USFS contracted with the Professional Services Group of geographic information systems (GIS) software and services pioneer ESRI ( www.esri.com ) to create the National Integrated Land System (NILS). The project developed a common data model, a workflow and a set of GIS software tools for the collection, management and sharing of land survey data and land record information.
The NILS FrameworkThrough its enterprise GIS environment, NILS meets a diverse set of requirements. The system stores spatial data representing the Public Land Survey System (PLSS), as well as the metes and bounds survey system of the 13 Colonies, and displays data from both urban and rural environments. NILS supports survey measurement data, yet it allows parcels to be created based on map control when more precise survey data is not immediately available. The NILS database integrates digitized data, scanned data, GPS data, land descriptions and aerial photography.
During the conceptual phase, ESRI conducted in-depth research and analysis to fully understand the BLM’s workflows, requirements and needs. This included meeting with other federal agencies, counties, local governments and private companies to see how they use BLM data and interact with the agency. From this analysis, a document was created and called “NILS-Concept of Operations and User Requirements.” This document laid the foundation and vision for how ESRI would go about building NILS in an interactive and incremental manner using commercial off-the-shelf (COTS) ArcGIS technology as the framework. The COTS foundation of ArcGIS was modified to accommodate the BLM’s business processes and routing of tasks within the NILS system. In short, using its COTS ArcGIS technology, ESRI built customized modules to meet the needs of the BLM and USFS workflows and business practices.
As a total package, the integration of surveying and GIS data in one system provides land managers with a more informed depiction of the public lands that are based on official record measurements and tied to the earth with real-time GPS coordinate data.
The NILS field-to-fabric data model is based on the topological integration of geometry across multiple feature tiers from the survey fabric to the land description fabric. The term “fabric” refers to the collection of features that share points at corners in a topological structure. When features in a fabric are edited, a change to a geometric element affects the shape of all features that are topologically tied to the edited features. This process is paramount for land records managers and those who maintain cadastral mapping databases to improve the efficiency, accuracy, quality and usability of cadastral data.
NILS consists of four modules: Survey Management, Measurement Management, Parcel Management and GeoCommuni-cator. In the Survey Management, Measurement Management and Parcel Management modules, survey measurement data and land records data are captured and analyzed, edited and committed to permanent records using a customized workflow and job-tracking methodology. Known to NILS users as the Workflow Manager and Task Assistant, these tools allow the BLM and USFS to define, organize and standardize their individual tasks within a workflow. They also allow each agency to automate tasks and track the status and progress of jobs from beginning to end.
“Workflow Manager and Task Assistant have greatly simplified the completion of day-to-day jobs,” says Michael D. Nedd, BLM assistant director for Minerals, Realty and Resource Protection. “These tools provide a routine, easy-to-learn, standard way of managing land records within NILS’ Survey Management, Measurement Management and Parcel Management modules.”
Survey Management and Measurement ManagementThe NILS Survey Management and Measurement Management modules allow NILS users to collect, analyze and adjust survey data. From a GIS desktop environment, they accept the combination of measurement data from a variety of sources with varying data reliabilities to create a seamless measurement network, also known as the survey fabric. Since these modules accept data with different levels of accuracy, the metadata in the NILS records contains information such as bearing standard deviation, the surveyor on record, survey type, source agency, field completion date, recordation date, instrument corrections and comments.
The Survey Management and Measurement Management modules contain tools to import data automatically, enter record survey data manually, analyze and modify record data, edge-match survey boundaries and adjust the data using the Least Squares Adjustment method. Additional tools allow users to perform geodetic COGO and section subdivision, create parcel geometries and export data. The points and lines in the measurement network can be used to create or update the polygons in the land description (LD) fabric. The LD fabric can then be used to electronically create the geometry for land and mineral-use records in the parcel fabric.
Together, NILS’ Survey Management and Measurement Management modules are bridging the disciplines of land surveying and GIS technologies in the federal sector, integrating this data into a user-friendly system that allows both specialists and land managers within the BLM and USFS to have a better understanding of the land boundaries and descriptions for lands under their jurisdiction.
Parcel ManagementThe Parcel Management module is a desktop GIS application that provides tools for land managers to create and manage parcel features and their land descriptions. Parcel features may include ownership, land-use rights and use-authorizations. The parcel fabric is vertically integrated with survey features captured and managed using NILS’ Survey Management and Measurement Management applications. Through this vertical integration, changes in the survey fabric can trigger changes to the land description and parcel fabrics.
Parcel Management provides a process for managing land and mineral records and cadastral feature data stored in the database model. The main purpose of the Parcel Management component is to spatially display land and mineral records. It is comprised of custom feature classes, tools and procedures for editing land records in a transactional, history-tracking environment. NILS enables users to construct and edit land description fabrics and to create required parcel fabrics from them. The data is organized by map themes, which provide a custom set of layers in NILS to support specific work activities such as recording mining claims, oil and gas leasing or right-of-way processing.
Land and mineral records are created or modified in the event of title transfer, land and mineral leasing or any number of land-use activities managed by the BLM. Multiple land and mineral records can occur on the same parcel of land, so they are maintained in the BLM’s Legacy Rehost 2000 (LR2000) system. The LR2000 system provides reports on BLM land and mineral use-authorizations for oil, gas and geothermal leasing; rights of way; coal and other mineral development; land and mineral title; mining claims; withdrawals; classifications; and more on federal lands or on federal mineral estate land.
The geometry for LR2000 land and mineral records is generated in NILS electronically by the Parcel Management’s Create/Maintain (C/M) engine. This application creates and/or updates the polygon geometry based on the textual aliquot part of the land description. The C/M application selects the land description building blocks and subdivides the land description fabric where needed. Land and mineral textual attribute information is stored with the geometry. The Parcel Management data is a separate feature from its land description building blocks. This automated process currently supports land and mineral records with textual land descriptions containing townships, sections, aliquot parts, lots and mineral surveys, as well as other survey types.
The bridge between survey measurements and the boundary lines portrayed in the enterprise GIS has increased the knowledge of land managers and the public alike. This information can be retrieved via the Internet by way of the fourth module, GeoCommunicator, for a wide variety of GIS applications.
GeoCommunicatorGeoCommunicator ( www.geocommunicator.gov ) is the NILS publication Web site that provides for the distribution and access of spatial data from all three of the NILS transaction applications. GeoCommunicator provides searching, accessing and dynamic mapping of data for federal surface-management boundaries, mining claims, land and mineral-use records, range allotments, conveyances, classifications, withdrawals, PLSS data, abandoned mines, BLM facilities and more. Land and mineral-use records include oil, gas, geothermal, coal and other mineral leasing, rights of way, land-use permits, mineral materials and more. GeoCommunicator provides for the downloading of the PLSS data in Shape file format. The survey-based points and horizontal control coordinates are available by request in ASCII (flat file) or GIS-coverage format.
Additionally, other GIS users and developers can use GeoCommunicator to provide Web and map services in a GeoRSS format (standard for encoding location as part of an RSS feed) such as finding and deriving a land description using latitude and longitude, finding PLSS land descriptions and using the Survey Exporter tool for downloading points, points/lines and horizontal control coordinates. Image and feature services are provided for all BLM map layers that can be used with GIS software to make maps, export data and combine with local data sets.
GeoCommunicator can be used for researching energy exploration and development, grazing use, determining land ownership and mineral rights, community planning, cadastral corner searching and more. Web site users utilize GeoCommunicator as a tool for researching public land and mineral record information. Users are able to find out what is occurring on a particular piece of land, including who manages the surface of the land. Through the Web site, users can find detailed land descriptions as well as various base maps such as aerial photography, topographic maps, BLM administration areas and federal surface-management agency boundaries. Based on feedback from the public, GeoCommunicator has proven to be a beneficial tool for those with interests in the fields of mining, energy, title, utility, surveying, education and the environment.
By embracing GIS as a framework that goes far beyond a single agency, organization or government entity, NILS has developed into a robust land records system that is greatly enhancing the quality and accessibility of land information in the United States. Proponents of NILS hope that this data and the system’s data model will one day serve as the foundation for a national multipurpose cadastre.