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This page last updated: 04/11/2007
Metadata created using Minnesota Geographic Metadata Guidelines
| Originator | Minnesota Land Management Information Center (LMIC) |
| Abstract | SECTIC-24K is a digital file of the Public Land Survey (PLS) section corners of Minnesota as recorded on the most recent edition of the U.S. Geological Survey's 1:24,000 7.5-minute quadrangle maps. The database attempts to best fit the section corner locations shown on the published 1:24,000 maps, even though better 'real world' data for the location of the section corner might be available elsewhere. The SECTIC-24K data set also includes a program which has the following utilities: Utility A: Section corner extraction from the SECTIC-24K database by county, 1:24,000-scale quad, or township. Utility B: Conversion among PLS, UTM, or LAT/LONG coordinates, either interactively or by file conversion. It also allows NAD27 - NAD83 conversions. Utility C: Creation of a dBASE output file from SECTIC-24K. (Version 1.1a fixes two bugs in Version 1.1: the file conversion option for UTM NAD83 to Lat/Long NAD83 now works and the program now runs on computers faster than 200 megahertz). |
| Browse Graphic | View a sample of the data. |
| Time Period of Content Date | |
| Currentness Reference | Section corner locations were recorded from the most recent edition of the U.S. Geological Survey's 1:24,000 7.5-minute quadrangle maps that were available at the time the dataset was created. Map dates ranged from the late 1940s to the late 1970s. |
| Access Constraints | None. |
| Use Constraints | Redistribution Conditions: In obtaining these data from LMIC, it is understood that you and/or your organization have the right to use them for any internal purpose. If you modify them, you should document those changes in a metadata record that should accompany all redistributed data. If you transmit or provide these data in any form to another user, the data MUST be accompanied by a copy of LMIC's disclaimer NOTICE.TXT and all documentation provided with the original data set including the full metadata record. |
| Distributor Organization | Minnesota Land Management Information Center (LMIC) |
| Ordering Instructions | This data set is distributed on the internet by clicking below after Online Linkage. Doing so will tell your browser to start downloading a self-extracting 'ZIP' file which will contain the following: - The SECTIC-24K data set, associated conversion utilities and documentation described in Entity and Attribute Overview element. - Metadata (.htm) file for the dataset - NOTICE.RTF, an important notice about this data set that can be read by most word processing software, and an ascii text version of the same notice (NOTICE.TXT) After downloading this self-extracting 'zip' file (which will have an 'exe' extension), simply execute (run) the file. (For example, you can double click it from Windows Explorer or File Manager). Doing this will automatically extract the files described above. You can then delete file types that you do not need, if any. If you do not have access to the Internet, contact LMIC to receive SECTIC-24K on diskette. |
| Online Linkage | Click here to download data. (See Ordering Instructions above for details.) By clicking here, you agree to the notice in "Distribution Liability" in Section 6 of this metadata. |
Go to Section:
1. Identification Information
2. Data Quality Information
3. Spatial Data Organization Information
4. Spatial Reference Information
5. Entity and Attribute Information
6. Distribution Information
7. Metadata Reference Information
| Section 1 | Identification Information | Top of page | ||
| Originator | Minnesota Land Management Information Center (LMIC) | |||
| Title | Minnesota Public Land Survey System Section Corner Database: SECTIC-24K, Version 1.1a | |||
| Abstract | SECTIC-24K is a digital file of the Public Land Survey (PLS) section corners of Minnesota as recorded on the most recent edition of the U.S. Geological Survey's 1:24,000 7.5-minute quadrangle maps. The database attempts to best fit the section corner locations shown on the published 1:24,000 maps, even though better 'real world' data for the location of the section corner might be available elsewhere. The SECTIC-24K data set also includes a program which has the following utilities: Utility A: Section corner extraction from the SECTIC-24K database by county, 1:24,000-scale quad, or township. Utility B: Conversion among PLS, UTM, or LAT/LONG coordinates, either interactively or by file conversion. It also allows NAD27 - NAD83 conversions. Utility C: Creation of a dBASE output file from SECTIC-24K. (Version 1.1a fixes two bugs in Version 1.1: the file conversion option for UTM NAD83 to Lat/Long NAD83 now works and the program now runs on computers faster than 200 megahertz). |
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| Purpose | This database was developed to provide section corner locations for mapping applications which use the U.S. Geological Survey's 1:24,000 7.5-minute quadrangle as a base map. | |||
| Time Period of Content Date | ||||
| Currentness Reference | Section corner locations were recorded from the most recent edition of the U.S. Geological Survey's 1:24,000 7.5-minute quadrangle maps that were available at the time the dataset was created. Map dates ranged from the late 1940s to the late 1970s. | |||
| Progress | Complete | |||
| Maintenance and Update Frequency | None planned | |||
| Spatial Extent of Data | Minnesota | |||
| Bounding Coordinates | -97.25 -89.50 49.40 43.50 |
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| Place Keywords | Minnesota | |||
| Theme Keywords | location, U.S. Public Land Survey, PLS, PLSS, PLS section corners, USGS 1:24,000 7.5-minute quadrangle | |||
| Theme Keyword Thesaurus | ISO 19115 Topic Category | |||
| Access Constraints | None. | |||
| Use Constraints | Redistribution Conditions: In obtaining these data from LMIC, it is understood that you and/or your organization have the right to use them for any internal purpose. If you modify them, you should document those changes in a metadata record that should accompany all redistributed data. If you transmit or provide these data in any form to another user, the data MUST be accompanied by a copy of LMIC's disclaimer NOTICE.TXT and all documentation provided with the original data set including the full metadata record. | |||
| Contact Person Information | Nancy Rader,
GIS Data Coordination Specialist Minnesota Land Management Information Center (LMIC) 658 Cedar Street, Room 300 St. Paul, MN 55155 Phone: 651-201-2489 FAX: 651-296-3698 E-mail: clearing.house@state.mn.us | |||
| Browse Graphic | View a sample of the data. | |||
| Browse Graphic File Description | ||||
| Associated Data Sets | Control Point Generated PLS (quarter-quarter section) The land survey information in this database is constructed using section corner coordinates (and other PLSS corners if available) from the Control Point Inventory as well as information from the original surveyors' notes and plat maps. Quarter-quarter section and government lot boundaries and meander corners are proportioned using Cadastral Measurement Management software from the U.S. Bureau of Land Management. Meander lines are added with ArcCOGO using the bearings and distances from the original survey notes. The section lines and Indian reservation boundaries are extended across water bodies, but the smaller subdivision lines are not. Attributes are included. See http://deli.dnr.state.mn.us/metadata/full/pls40ne3.html Minnesota Public Land Survey System: TRS (Township, Range, Section) This dataset contains all PLSS section and township boundaries as well as county boundaries for Minnesota. The data were digitized from USGS 1:100,000-scale maps. All lines were extended across water bodies. Attributes are included. A statewide file is available online. See http://www.lmic.state.mn.us/chouse/metadata/trs.html Minnesota Public Land Survey System: TRSQ (Township, Range, Section, Quarter-quarter) This dataset contains county, township, range, and section boundaries digitized at LMIC from USGS 1:100,000-scale maps. Quarter-section and quarter-quarter section subdivisions were calculated using the digitized sections. All lines were extended across water bodies. Attributes are included. See http://www.lmic.state.mn.us/chouse/metadata/trsq.html Mn/DOT BaseMap Section lines digitized from USGS 7.5-minute quadrangle maps. The dataset does not include attributes. See http://www.dot.state.mn.us/tda/basemap/metadata/Section.htm Control Point Inventory, Minnesota Department of Natural Resources (MnDNR) This is a multi-agency effort to create a database that provides a comprehensive public land survey point referencing system. It is intended to hold the most current and accurate set of coordinate points which can be used as a GIS base layer. A coordinate value for each PLSS section corner was obtained by digitizing 1:24,000 USGS quad maps. SECTIC 24K was used as one source of information to construct the Control Point Inventory. As available, more accurate coordinates and PLSS points to the 40 corner or the government lot level are added. For more information, contact Larry Swenson at 651-297-3793. |
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| Section 2 | Data Quality Information | Top of full metadata | Top of page | |
| Attribute Accuracy | Unknown (see Lineage element for description of tests performed during data set creation). | |||
| Logical Consistency | Not applicable | |||
| Completeness | Section corner locations are complete statewide. Corner locations were projected in cases where the corners were not printed on the source map. | |||
| Horizontal Positional Accuracy | Locational accuracy for points derived from USGS 7.5-minute quadrangles cannot be assumed to exceed National Map Accuracy Standards for 1:24,000 scale maps (+/- 40 feet). (See Lineage element for description of tests performed during data set creation.) | |||
| Vertical Positional Accuracy | Not applicable | |||
| Lineage | HISTORY OF THE SECTIC-24K DATABASE: In the early 1980s, the Minnesota Land Management Information Center (LMIC) created a data file of the location of the State's Public Land Survey (PLS) section corners. The file, which was given the name 'GISMO', was created by digitizing the section corners from the U.S. Geological Survey topographic quadrangle maps. These maps were the most detailed set of base maps available statewide at that time. For most of the state, 1:24,000 scale maps were used. However, for nearly 20% of the state, only 1:62,500 scale maps were available. All section corners shown on the published maps were recorded. Because of the use of this original database, all four corners of a given section needed to be digitized. Therefore, section corners were 'projected' to complete any section not completely shown on the quadrangle maps. Section corners were 'projected' by extending the published section line segments into areas such as meandered waters, at survey base changes and across the state border. Some things to keep in mind about the original GISMO data: 1. It must be remembered that the section corner locations on the quadrangle maps were only as good as the information available when the map was made. The maps used for this project were published from the late 1940s to the late 1970s. National Map Accuracy Standards for 1:24,000-scale maps is plus or minus 40 feet for identifiable objects. In many cases, section corners are not easily located during map compilation. Therefore, section corner locations from this source might be described as a 'caricature' of the land net and are highly generalized. The GISMO database was designed to best approximate the location of the section corner 'map feature' as shown on the published quadrangle map, even though more precise data might have been available from other sources for selected section corners. 2. The digitizing was done from printed paper maps. Because of changes in temperature and humidity conditions, the paper maps could shrink or expand up to 1/8 of an inch which is not uniform in all directions across the map. Thus, error in the digital file of this magnitude could be expected. 3. The digitizing technology of that time was 'blind'; that is, the person digitizing could not visualize and verify the data interactively. Later, the data was visually checked by the creation of plots to overlay on county maps of that vintage (scales of 1:126,720 for most of the state and 1:63,360 for the Twin Cities metro area). However, the data was never systematically checked at the 1:24,000 scale with the original quadrangle map. 4. The data was captured on a township-by-township basis. It took anywhere from one to four quad maps to display an entire township. The section corners in a township were captured as one of 49 points. Because of this format, common corners along a township border were digitized two, three, or even four times. The data for these points was later processed to establish the same coordinate values for the multiple records representing a specific section corner. 5. The data was captured in UTM meters, NAD27 in UTM Zone 15 extended. These values were calculated for each section corner based on the digitized latitude/longitude coordinates from the corners of each quadrangle base map. The statewide data file was organized by county, township and range. Conversions can be made to other units of measurement, NAD83, and other projections. However, the accuracy of those conversions will only be as good as the conversion program allows. And of course, these programs cannot improve the quality of the coordinate values from the original data. In spite of all these shortcomings, the data set is still very useful. Many people in various county, regional, and state-wide inventory programs use the 1:24,000 quad as a base map. Many mapping applications require the section corners or lines for reference. This database will be very adequate for this purpose. UPDATES TO THE GISMO DATA Since the completion of the GISMO file in the mid-1980s, some section corner values have been edited and updated to better reflect the published 1:24,000 quadrangle maps. Most of these updates have occurred in the forested area of Minnesota. In 1992, LMIC systematically analyzed the approximately 20% of the state that was originally digitized from old 1:62,500 quads. The resulting file, SECTIC-24K, is a better representation of the section corners as shown on current 1:24,000 quad maps. During the first half of 1992, about 20% of the old GISMO points in the state were reviewed and many were revised as part of the Control Point Inventory Project using the following process: 1. Plot the GISMO points for old 1:62,500 scale map areas A 1:24,000-scaled plot was made for 333 quads which showed the following information: United States Geologic Survey (USGS) quad tics and an identification code; USGS quad outline; the GISMO points (as digitized from 1:62,500 maps); and the GISMO code which consists of county, township, range, direction and corner. 2. Visually edit the plot For these 333 quads, the old GISMO section corner location was plotted as a circle with the radius of .05 inch at the 1:24,000 scale (this is about 100 feet in ground scale). The method used to check positional accuracy was to overlay the plot on the published USGS quad map and use a 'best fit' of the published quad boundary to the plotted quad boundary. If the section corner tic shown on the current USGS 1:24,000 quad map did not fall within the .05 inch circle, the point was then highlighted for revision. The GISMO and county codes were also checked and highlighted where changes were needed. As stated previously, the computer processing for the GISMO effort required complete sections (4 corners). If a corner was not shown on the quad map, 'projected' points were added to build a complete section. 'Projected' points were added to the file when a corner needed to complete a section was: A: in a meandered water body B: beyond the state's border C: across a county line (e.g., along the Mississippi River) D: across the Prime Meridian line from the original land survey, or E: no clear intersection shown on USGS quad for any other reason 3. Correct the section tics to the 1:24,000 quads Section corner tics beyond a .05 inch locational tolerance shown on the check plot had been highlighted in the visual editing. The highlighted tics were redigitized and coded to show that the locational values had been changed from old GISMO values. Then any other observed coding problems, such as county code, were resolved statewide. Note: multiple records for some points still exist in some cases because of the reasons stated in item #2 above. 4. Verify changes on 1:24,000 quads On quads where changes had occurred, the data was re-plotted at 1:24,000 to verify that all the positions were corrected and that any coding corrections were done. 5. Proof entire state file Two steps were used to review the final file. First, LMIC plotted the whole state as a set of 1:100,000 map sheet blocks and compared them to published USGS 1:100,000 quad maps to proof county boundaries and projected points. This also served as a double check for any other problems that might have been in the original GISMO points. A second proof was done with the help of MN-DNR's Division of Minerals staff. They compiled a complete statewide section line mapping file by connecting the SECTIC-24K corner tics. A few problem areas were identified and have been revised. 6. Translate to NAD83 All of the section corner data points were translated into NAD83 using the National Geodetic Survey's NADCON program. This conforms to state law requiring use of the 1983 datum. The final master SECTIC-24K database is housed at LMIC. It is organized as a state file containing about 120,000 records and is sorted geographically (county, township, range, section). NOTE - The location values for all revised points were collected as 'double precision' values. In addition, all other points carried over from the old GISMO file were converted to double precision values. However, for the SECTIC-24K file, the locational data has been truncated to the nearest whole meter. Remember, the locational values in the SECTIC-24K database should never be assumed to be that accurate. This data file only attempts to reflect the published quad maps with all the faults listed above. Other sources of data should be used to produce maps reflecting the best 'real world' location of these section corners. 7. Fix two bugs in Version 1.1 Version 1.1 contained two known bugs: 1. the option to convert a file of coordinates from UTM NAD83 to Lat/Long NAD83 did not work correctly, and 2. a problem with the runtime compiler resulted in a 'Runtime Error 200' message when trying to start SECTIC on computers that are 200 megahertz or faster (the program would not run). Version 1.1a fixes these two problems. |
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| Source Scale Denominator | 24000 | |||
| Section 3 | Spatial Data Organization Information | Top of full metadata | Top of page | |
| Native Data Set Environment | Compressed binary which is exportable to dBase format. | |||
| Geographic Reference for Tabular Data | PLS, Lat/Long, UTM | |||
| Spatial Object Type | ||||
| Vendor Specific Object Types | Not applicable | |||
| Tiling Scheme | State. User may select by county, 1:24,000-scale quad, or township. | |||
| Section 4 | Spatial Reference Information | Top of full metadata | Top of page | |
| Horizontal Coordinate Scheme | UTM | |||
| Ellipsoid | GRS80 | |||
| Horizontal Datum | NAD83 | |||
| Horizontal Units | Meters | |||
| Distance Resolution | Unknown | |||
| Altitude Datum | Not applicable | |||
| Altitude Units | Not applicable | |||
| Depth Datum | Not applicable | |||
| Depth Units | Not applicable | |||
| UTM Zone Number | 15E | |||
| Coordinate Offsets or Adjustments | None | |||
| Section 5 | Entity and Attribute Information | Top of full metadata | Top of page | |
| Entity and Attribute Overview | The SECTIC-24K data set contains the following files: 1. SECTIC.DAT: A compressed version of the statewide database containing NAD27 and NAD83 values of the section corners, indexed by PLS coordinates 2. TOWN: File of township names 3. COUNTY: File of county names 4. Q24: File of 24K quad names 5. Q100: File of 100K quad names 6. Q250: File of 250K quad names 7. SECTIC.EXE: A program which includes the following utilities: Utility A: Section corner extraction from the SECTIC-24K database by county, 1:24,000-scale quad, or township. Utility B: Conversion among PLS, UTM, or LAT/LONG coordinates, either interactively or by file conversion. It also allows NAD27 - NAD83 conversions. Utility C: Creation of a dBASE output file from SECTIC-24K 8. SECTIC.HLP: Help file for SECTIC-24K program 9. SECTIC24K.PDF: Documentation file (also in Word and WordPerfect 5.1 formats, with graphics in .EPS or in high or low resolution .TIFF formats) 10. READ.ME: Installation instructions 11. SHAPE.TXT: Instructions for converting SECTIC output to shapefile format using Excel and ArcView3.x. Note: If the dBase file creation option is chosen, the resulting three databases will have the following fields: 1. SECTIC.DBF contains the following fields for each section corner: CNTY -The county number of the section corner. Corners on county borders appear once for each county. TOWRAD - 6 digit identifier concatenated from 3 digit township, 2 digit range and 1 digit direction. Used to index into TOWNSHIP.DBF name file. TIC - Corner number in township, from 1 to 49. UTMX27, UTMY27 - NAD27 coordinates for UTM X and Y. LAT27, LONG27 - Latitude and longitude in NAD27, in decimal degrees. UTMX83, UTMY83, LAT83, LONG83 - NAD83 versions of above. QUAD - Index into QUAD.DBF; file of quad names. CODE - PJ = projected; CR = corrected; NC = No Change 2. TOWNSHIP.DBF contains the following fields: CNTY - 2 digit county number. TOWRAD - 6 digit TOWRAD identifier as in SECTIC.DBF above. TOWNNAME - Township name 3. QUADS.DBF contains the following fields: QUAD - Index number, as in SECTIC.DBF NAME24K - USGS 24K quad name NAME100K - USGS 100K quad name NAME250K - USGS 250K quad name |
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| Entity and Attribute Detailed Citation | SECTIC24K.PDF | |||
| Section 6 | Distribution Information | Top of full metadata | Top of page | |
| Publisher | Minnesota Land Management Information Center (LMIC), Minnesota Planning | |||
| Publication Date | 1999 | |||
| Contact Person Information | Nancy Rader GIS Data Coordination Specialist Minnesota Land Management Information Center (LMIC) 658 Cedar Street, Room 300 St. Paul, MN 55155 Phone: 651-201-2489 FAX: 651-296-3698 E-mail: clearing.house@state.mn.us |
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| Distributor's Data Set Identifier | sectic | |||
| Distribution Liability | DISTRIBUTION LIABILITY STATEMENT For data delivered on-line or by physical media by The Land Management Information Center Limitations: Although extensive effort has been made to produce error free and complete data, all geographic information has limitations due to the scale, resolution, date and interpretation of the original source materials. You should consult available data documentation (metadata) for these particular data to determine their limitations and the precision to which they depict distance, direction, location or other geographic characteristics. These data may be subject to periodic change without prior notification. No Warranty: These data are provided as is, without any warranty whatsoever, including but not limited to any warranty as to their performance, merchantability, or fitness for any particular purpose. Liability: The entire risk as to the results of the use of these data is assumed by the user. LMIC is not responsible for any interpretation or conclusions based on these data made by those who acquire or use it. LMIC shall not be liable for any direct, indirect, special, incidental, compensatory or consequential damages or third party claims resulting from the use of these data, even if LMIC has been advised of the possibility of such potential loss or damage. In States that do not allow the exclusion or limitation of incidental or consequential damages, you may not use these data. Redistribution Conditions: In obtaining these data from LMIC, it is understood that you and/or your organization have the right to use them for any internal purpose. If you modify them, you should document those changes in a metadata record that should accompany all redistributed data. If you transmit or provide these data in any form to another user, the data MUST be accompanied by a copy of this disclaimer and all documentation provided with the original data set including the full metadata record. Data Delivered on Electronic Media: If these data have been requested from LMIC on magnetic media, CD-ROM or any other physical media, LMIC will deliver this product in the computer-readable format agreed upon with the requestor. LMIC will re-issue these data if they are determined unreadable by correctly adjusted computer input devices, or when the medium is delivered in a damaged condition. Requests for re-issue of this digital data product must be made within 30 days of the date shipped from LMIC. |
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| Transfer Format Name | Compressed binary which is exportable to dBase format. | |||
| Transfer Format Version Number | ||||
| Transfer Size | 1.8 MB compressed | |||
| Ordering Instructions | This data set is distributed on the internet by clicking below after Online Linkage. Doing so will tell your browser to start downloading a self-extracting 'ZIP' file which will contain the following: - The SECTIC-24K data set, associated conversion utilities and documentation described in Entity and Attribute Overview element. - Metadata (.htm) file for the dataset - NOTICE.RTF, an important notice about this data set that can be read by most word processing software, and an ascii text version of the same notice (NOTICE.TXT) After downloading this self-extracting 'zip' file (which will have an 'exe' extension), simply execute (run) the file. (For example, you can double click it from Windows Explorer or File Manager). Doing this will automatically extract the files described above. You can then delete file types that you do not need, if any. If you do not have access to the Internet, contact LMIC to receive SECTIC-24K on diskette. |
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| Online Linkage | Click here to download data. (See Ordering Instructions above for details.) By clicking here, you agree to the notice in "Distribution Liability" above. | |||
| Section 7 | Metadata Reference Information | Top of full metadata | Top of page | |
| Metadata Date | 04/11/2007 | |||
| Contact Person Information | Nancy Rader,
GIS Data Coordination Specialist Minnesota Land Management Information Center (LMIC) 658 Cedar Street, Room 300 St. Paul, MN 55155 Phone: 651-201-2489 FAX: 651-296-3698 E-mail: clearing.house@state.mn.us |
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| Metadata Standard Name | Minnesota Geographic Metadata Guidelines | |||
| Metadata Standard Version | 1.2 | |||
| Metadata Standard Online Linkage | http://www.lmic.state.mn.us/gc/stds/metadata.htm | |||
This page last updated: 04/11/2007