Finding and Documenting Sample Locations

Chapter 4 Finding and Documenting Sample Locations Overview All 2001 NRI information for PSU and point measurement and classification will always be collected at exactly the same locations that were used to collect information for the 2000 or 1997 NRI. There are no exceptions. All data collection for 2000 core PSUs was collected at the same location as 1997 collection. If 2000 data were not collected in the same location as 1997, data gatherers are to contact ICCS leaders for guidance before proceeding with data collection for the PSU. The 1997 NRI sample locations shall be determined using information in the PSU file folder. A 2001 NRI PSU support map (or digital equivalent) with 1997 NRI sample locations will be used by the data gatherer to record and document 2001 conditions and changes in accordance with the instructions in chapter 5. 4.1 Key Points Key definitions, materials needed for finding and documenting PSU and point locations, and spatial materials provided for the 2001 NRI are detailed in this section. Definitions Digital Raster Graphic (DRG). A scanned image of a U.S. Geological Survey (USGS) standard series topographic map, including all map collar information. The image inside the map neatline is georeferenced to the surface of the Earth and fit to the Universal Transverse Mercator projection. The horizontal positional accuracy and datum of the DRG matches the accuracy and datum of the source map. The map is scanned at a minimum resolution of 250 dots per inch. [USGS] http://remotesensing.org/geotiff/geotiff.html GeoTIFF. A public domain extension of the TIFF standard. GeoTIFF files conform to the TIFF 6.0 base standard, but contain additional information that allows image coordinates to be transformed to ground coordinates. TIFF readers that do not recognize GeoTIFF tags can still read GeoTIFF files as ordinary TIFF data. The GeoTIFF home page is at: [NRI-2000] http://www.remotesensing.org/geotiff/geotiff.html Preliminary 2001 NRI PSU Support Map. A preliminary (unverified) spatial representation of the PSU boundary and labeled point locations. The official NRI spatial database is the source for this map [NRI 2001]. Preliminary 2001 NRI PSU and Point Site Map. A preliminary (unverified) spatial representation of the PSU boundary and labeled point locations on a DRG background. The official NRI spatial database is the source for this map [NRI 2001]. PSU and Point Site Map. A spatial representation of the PSU boundaries and point locations after locations are verified as the same as those used in the 1997 Foundation NRI. The PSU and Point Site Map includes a DRG background. The official NRI spatial database is the source for this map. [NRI2000] 2001 NRI (August 20, 2001) — 4–1 Chapter 4 Finding and Documenting Sample Locations PSU File Folder. The folder containing all the original reference materials including the 1982 PSU Base Map, the 1987 PSU photography or map, the 1992 PSU photography or map, the 1997 PSU photography or map, PSU soils maps, PSU Support Maps for each year the PSU was included in the sample, and other data collection materials used for resources inventories. [NRI-97] PSU Support Map. A map used as a permanent record to document the extent and location of where data elements were collected. A separate PSU Support Map is created for each PSU. A different PSU Support Map is created for each new data collection activity for which the PSU is included in the inventory sample. [NRI-97] Verification. The process of verifying the accuracy of locations of the PSU boundary and point locations on the PSU Support Map. [NRI-2000] Materials Used for Finding and Documenting Sample Locations • PSU file folders containing maps, photography, and 1997/2000 PSU Support Map that depict PSU boundary and sample point locations used for 1997/2000 NRI data collection. • Preliminary 2001 PSU and Point Site Map representing the digitized PSU boundary and points on a digital raster graphic DRG background. This map is used to: — Compare 1997/2000 data collection locations with the 2001 NRI spatial database. — Aid in finding the PSU and point locations on 2001 photography. • Preliminary 2001 NRI PSU Support Map showing the PSU boundary and points without a DRG background. This map may be used to document 2001 conditions and changes after verifying point locations and boundaries and scaling to the 2001 photography. • Historical data can be used to locate sample locations. Examples include current soils data must agree with the historical record, land cover/use must be compatible with that previously observed, the census water will most time match historical data or the reason for the difference will be apparent. • Other materials that allow data to be collected year after year at the same location. Materials Provided The National Cartography and Geospatial Center, Resources Inventory Support Branch (RISB), Fort Worth, Texas, furnished ICCSs the following: • Preliminary 2001 PSU and Point Site Maps for all PSUs. • Preliminary PSU Support Maps for all PSUs. • DRG in GeoTIFF format for each PSU. • PSU centered DOQ GeoTIFF, where available, were provided to users of digital materials. These materials were provided on CD-ROMs that included information from the digitized PSU boundary and point locations in the national NRI spatial database as of March 2001. Examples of the site and support map forms are provided in Location figures 1 and 2. Note: The preliminary 2001 PSU and Point Site Map and preliminary 2001 NRI PSU Support Map are considered preliminary until their spatial information has been verified by the data gatherer. Preliminary maps may not accurately depict the location of data collection for 1997 NRI or the 2000 sample boundaries and points if the NRI spatial database has not been updated or corrected. 2001 NRI (August 20, 2001) — 4–2 Chapter 4 Finding and Documenting Sample Locations Location figure 1 Preliminary 2001 NRI PSU and Point Site Map 2001 NRI (June 25, 2001) — 4–3 Chapter 4 Finding and Documenting Sample Locations Location figure 2 Preliminary 2001 NRI PSU Support Map 2001 NRI (June 25, 2001) — 4–4 Chapter 4 Finding and Documenting Sample Locations 4.2 Procedure for Finding and Verifying PSU and Point Locations What to do if the PSU file materials are missing or prior data collection location can not be determined—If PSU file folders are missing or do not indicate where information was collected for the 2000 or 1997 NRI, the data gatherer is required to contact the ICCS leader. The leader is to provide guidance and assistance in obtaining the materials or information needed before data collection can begin. PSUs where materials are missing and have been downloaded to the CASI may be returned to the ISU database by answering NO to the following CASI question: Can you determine where data were gathered for the 1997 or 2000 NRI? After information and/or materials are obtained, the PSU is to be downloaded from the ISU database and data entry completed. Comparing preliminary 2001 NRI PSU Support Map with historic data collection locations—Procedures for comparing preliminary 2001 NRI PSU Support Maps are slightly different for core and rotation sample PSUs. All 2001 PSU Support Maps are to be considered preliminary until the accuracy of the locations of all PSU points and boundaries are verified. Always collect the data in the location where it was last collected. For the 2001 NRI, that means the 2000 location for core PSUs and the 1997 location for the rotation PSUs. Note that the 2000 data were to be collected at the 1997 location. Collecting data at the same location means collect data on the same land cover/use, wetland classification, or other characteristic of the location where data were last collected. It does not mean the place defined by x-y coordinates as listed in support materials if that place has a different land cover/use, wetland classification, or other characteristics. In reviewing the materials remember that all information should be used to determine the location of actual data collection. Remember that the previous data gatherer had to use judgment in locating boundaries and points for data collection, and that a point could only be located to tolerance consistent with materials. The location at which data were actually collected is not necessarily the location identified by placing a Mylar overlay with the labeled point over the photo. It is not necessarily the location obtained from the GIS file. An important piece of information to use in determining the actual location of data collection is the land cover/use reported for the point. Data were collected for core sample PSUs in the 2000 NRI while data have not been collected on the rotation sample PSUs since 1997. All data for rotation PSUs are to be collected at the same locations as those of the 1997 NRI data collection. The core PSUs should be collected at the 2000 location, which implies the 1997 location. If it is determined that the 1997 and 2000 data locations are not the same, contact the ICCS leader for further instructions before data collection can begin. A CASI question asks if the 1997 and 2000 data collection locations are the same for core PSUs. Compare the preliminary 2001 PSU Support Map with the 2000 PSU Support Map and 2000 photography for core sample PSUs, or the 1997 PSU Support Map and 1997 photography for rotation sample PSUs. The preliminary 2001 PSU and Point Site Map may be used to provide a visual background for point and boundary locations from the NRI spatial database. Detailed instructions for CASI entry related to PSU and point locations are in Chapter 5.1, Data Collections Instructions. 2001 NRI (June 25, 2001) — 4–5 Chapter 4 Finding and Documenting Sample Locations Compare PSU Support Map labels—Check the FIPS and PSU and all point labels. Correct any errors on the 2001 PSU Support Map. Compare PSU Support Map point and boundary locations: • If the 2001 spatial point locations are separated from the 2000 or 1997 point locations by less than 50 feet, the geospatial point location is acceptable. Check all points. • If the PSU boundary’s vertices or lines diverge by less than 50 feet from the 2000 or 1997 PSU boundary, the spatial PSU boundary is acceptable. • If all point and boundary locations are correct, the preliminary 2001 PSU Support Map is considered verified and is no longer considered preliminary. • If point or boundary locations are found to be incorrect, the preliminary 2001 PSU Support Map is to be corrected or a new PSU Support Map is to be developed before data are collected. See section 4.5, Submitting Corrections for the National NRI Spatial Database. Note: Comparing 2001 PSU Maps with historic materials may require enlarging or reducing the 2001 materials to match the print size of historic materials. An RISB technical paper on procedures for adjusting map scales is available at the NRI Help Desk. Location table 1 summarizes actions that are to be taken when PSU location, points, and label errors are found. Location table 1 Findings and actions to correct PSU Support Maps Compare information on the preliminary 2001 NRI PSU Support Map to 2000 or 1997 NRI sample locations and labels Actions taken if the locations or labels on the preliminary 2001 NRI PSU Support Map do not match 2000 or 1997 NRI sample locations and labels FIPS or PSU label does not match PSU boundary does not match Point locations do not match Point label number does not match Point is outside of PSU boundary Correct the FIPS or PSU label on the preliminary 2001 NRI PSU Support Map Correct the boundary on the preliminary 2001 NRI PSU Support Map Correct the location on the preliminary 2001 NRI PSU Support Map Correct the label on the preliminary 2001 NRI PSU Support Map Point has had data collected in the past and is a valid sample point. Collect data. Enter a Note indicating that point is outside the PSU boundary. 2001 NRI (June 25, 2001) — 4–6 Chapter 4 Finding and Documenting Sample Locations 4.3 Verifying 2001 PSU Support Map If preliminary 2001 PSU Support Map labels, boundaries, and locations exactly match the 2000 or 1997 NRI data collection location, the 2001 PSU Support Map may be used for data collection. Data gatherers are to verify the map by affixing the name(s) of the data gatherer(s) and date of verification to the map. If the PSU boundary, point locations, or the labels are incorrect, the preliminary 2001 NRI PSU Support Map may be corrected and verified for use in gathering data. PSUs requiring corrections must have the materials identified in section 4.6 submitted to RISB to correct the spatial database (see section 4.6). If preliminary 2001 PSU Support Map errors or inconsistencies are identified and the map is unusable, the preliminary map must be discarded and a new 2001 PSU Support Map is to be developed. The 2001 PSU Support Map is developed on a blank Mylar and includes the following information: • State and county name (top left) • FIPS and PSU ID (top right) • PSU boundary (1997) • Sample points locations with number labels (1997) • North arrow (top of page) • Map scales (ratio and bar) • Registration marks to the 2001 image • Title: “2001 NRI PSU Support Map” • Name of the verifying data gatherer(s) and date of verification The verified 2001 PSU Support Map shall be used for all 2001 NRI data collection, as stipulated in chapter 5, and shall be permanently retained in the PSU file folder as part of the reviewable record. 4.4 Determine 1997 NRI Sample Locations on the 2001 Imagery Base Register the verified 2001 PSU Support Map on the 2001 photography base. This may require enlarging or reducing the scale of the PSU Support Map. Ensure that the 2001 PSU Support Map boundary and point locations are the same as those of the 2000 (core PSU) or 1997 (rotation PSU) NRI data collection location. Verify that the 2001 photography includes the entire PSU area. If the 2001 photography does not include the entire PSU area, halt data collection and notify the ICCS leader requesting guidance. Suitable 2001 photography must be obtained or data must be collected onsite. 2001 NRI (June 25, 2001) — 4–7 Chapter 4 Finding and Documenting Sample Locations 4.5 Documentation on PSU Support Maps Each module of data collection instructions in chapter 5 identifies the specific documentation requirements. Sample location figure 3 is a diagram of the process of verifying and using the 2001 support map. Location figure 3 Process for verifying and using 2001 support map Preliminary 2001 PSU and Point site maps Core PSUs • Determine 2000 NRI locations (and therefore 1997 NRI location) from PSU file folder • Compare w/ PSU boundary point locations and labels on preliminary maps Chapter 4 Verify locations Rotation PSUs • Determine 1997 NRI locations from PSU file folder • Compare with PSU boundary point locations and labels on preliminary maps Co rre cti on s Update geospatial database NCGC rr Co ect ion s • Conduct PI of farmstead, built-up, transportation, water areas (chapter 5) PI 2001 imagery • Conduct PI of farmstead, built-up, transportation, water areas (chapter 5) Chapter 5 • Delineate farmstead, built-up, transportation water areas per chapter 5 Develop 2001 PSU support map • Delineate farmstead, built-up, transportation water areas per chapter 5 If change from 2000 to 2001 • Delineate areas of change If change from 1997 to 2001 • Delineate areas of change Maintain as 2001 Documentation in PSU file folder 2001 NRI (June 25, 2001) — 4–8 Chapter 4 Finding and Documenting Sample Locations 4.6 Submitting Corrections for the National NRI Spatial Database If the 2000 or 1997 PSU and point information is not correct on the preliminary 2001 PSU and Point Site Map (with DRG background), corrections can be made directly to the site map. If the 2000 or 1997 PSU and point location information is not visible on the preliminary 2001 PSU and Point Site Map, all corrections are to be compiled on the original quadrangle compilation map used for the 1992 digitizing. PSU boundaries and points shall not overlap with other PSU boundaries or points. Contact the ICCS leader if there are any overlapping PSU polygons. If the original quadrangle compilation materials are not available, contact the NRI Help Desk for assistance. Submit PSU file folder containing reference materials that show where the 2000 or 1997 data were collected. Send either the corrected 2001 PSU and Point Site Map or the original quadrangle compilation maps, as referenced above, and the file folder materials. All corrections for the PSU spatial data layer will be performed by RISB on a county-by-county basis. Corrections to the NRI spatial database are to be submitted immediately following the completion of data collection for a county. If PSU materials are submitted without sufficient or correct accompanying materials (i.e., no PSU compiled on topographic or not in file folder) edits cannot be completed and materials will be returned. RISB will use the original materials to verify that the requested changes are correct before any PSU spatial information is updated. For security, the data collection facility should maintain a photocopy of the source materials forwarded to RISB. Submit all materials to Bill Adams at: U.S. Postal address FedEx address USDA-NRCS National Cartography and Geospatial Center P.O. Box 6567 501 West Felix Street Fort Worth, TX 76115 USDA-NRCS National Cartography and Geospatial Center Mail Room, Building 23 501 West Felix Street Fort Worth, TX 76115 All original materials will be returned to the data collection facility when RISB has completed correcting the NRI spatial database. 2001 NRI (August 20, 2001) — 4–9