MN GIS/LIS NEWS
The Newsletter of the Minnesota GIS/LIS Consortium
Table of Contents
MN GIS/LIS Consortium
From the Chair
Past News Issues
Statewide LiDAR Update
LiDAR for Conservation
Geology/Ground Water Info
Goodhue Flood Site
LOGIS gGov Project
Winona Township Atlas
SMSC Presettlement Map
USGS Digital Map
FSA Photos '09
Congress & GIS Governance
Air Quality Maps
Presidential Election Map
Monmonier at UofM
Scandia Resource Plan
Goodhue Land Use Model
Memorium: Bob Marx
ASPRS 2011 Conference
|New Statewide City, Township, and Unorganized Territory (CTU) Data
By Anna Brenes and Christopher Cialek, MnGeo
The Minnesota Geospatial Information Office (MnGeo), formerly the Land Management Information Center (LMIC), has created two new statewide data products containing updated information about cities, townships, and unorganized territories (CTU).
A shapefile, called MnCTU09, includes updated statewide CTU boundaries obtained from annexation and detachment dockets approved by the Office of Administrative Hearings Municipal Boundary Adjustment Unit (MBAU) through April 2009.
The data set is a medium-scale (nominally 1:24,000) representation created as part of a legislatively mandated project to calculate a table of township acreage data for the Minnesota Department of Revenue. The basemap selected to create the MnCTU09 data set consists of Mn/DOT’s internal municipal boundary file, which provided the most comprehensive coverage of annexation data through February 2008. MnGeo checked, updated and reformatted that file through the following processes:
Figure 1. Exampleof boundary digitization using the Traverse COGO tool.
- For annexations that included formal legal descriptions, applied ESRI’s Traverse COGO tool in ArcMap 9.2 to insert new boundaries,
- For annexations that included georeferenced maps, digitized the boundaries using 2008 aerial photography and the Public Land Survey section line data.
- Remaining annexation boundaries, those without either formal legal descriptions or georeferenced maps, were digitized by “intent”. Boundaries were digitized based on intent of the legal descriptions and interpreted using area measurements and relative positions of hand-drawn features. These areas may be less accurate than data entered using georeferenced maps or the Traverse tool.
After updating city, township, and unorganized territory boundaries and resolving gap and overlay issues, attribute information was refined to include acreage values, the Geographic Names Information System Feature Identifiers and other standard fields. Access MnCTU09 data at: http://www.lmic.state.mn.us/chouse/metadata/mnctu09.html
CTU Identification Codes
Working with its partners on the Governor’s Council Standards Committee, MnGeo has published a database of current CTUs together with their formal GNIS Feature identification codes. These codes represent a state-recognized standard: Codes for the Identification of Cities, Townships and UnorganizedTerritories (CTUs) in Minnesota.
The Minnesota CTU Database is the official repository for names and unique identifiers for cities, townships and Census-defined unorganized territories in Minnesota. A unique identifier for each entry in the database complies with Minnesota’s state CTU standard and with the national ANSI INCITS 446-2008 standard. At the Minnesota CTU Database web site, options to access the data include:
- Downloading the entire database
- Browsing via an interactive database search
- Following instructions for implementing a web service that can be integrated into remote applications without having to store the data locally