Attachment B - Instructions for 3DEP Project Creation and Delivery Scheme_1.pdf

US Geological Survey Broad Agency Announcement for 3D Elevation Program (3DEP)

DOIGFBO200046/G20AS00104

Attachment B Instructions for 3DEP Project Boundary Creation and Delivery Scheme

For background information on the Defined Project Boundary see the “collection” and “tiles” sections of the 3DEP Lidar Base Specification available at:

https://www.usgs.gov/3dep/lidarspec

3DEP lidar data must follow a set of collection requirements to achieve a consistent national dataset. These requirements include:

1. The Defined Project Area (DPA) must be the Area of Interest (AOI) plus a 100-meter buffer.

2. Data collection is required for the full extent of the DPA.

3. All products must be produced to 3DEP and Task Order requirements up to the edge of the DPA and no further.

4. Project deliverables will be delivered in the coordinate reference system(s) (CRS) and tiling scheme of the applicant’s choosing.

5. The CRS(s) used must be registered with the European Petroleum Survey Group (EPSG).

6. All tile indices must be clipped to the DPA

I. Select Tiling Scheme and Coordinate Reference System

3DEP BAA project deliverables will be delivered in the coordinate reference system(s) (CRS) and tiling scheme of the applicant’s choosing. If the applicant does not have a preferred tiling scheme, the 3DEP National Indexing Scheme is available for use. The 3DEP National Indexing Scheme is designed to be used with Albers Equal Area CRS (EPSG 6350). It is available as a map service for visualization and also for download as a File Geodatabase, a Shapefile, or a GeoPackage from an FTP site.

II. Geoprocessing Steps:

Step 1: Create the AOI using a CRS recognized and published by the EPSG. The boundary must be created in the same CRS it will be delivered in.

Each project must be processed and delivered in a single CRS, except in cases where a project area covers multiple CRSs such that processing in a single CRS would introduce unacceptable distortions in part of the project area. In such cases, the project area is to be split into subareas appropriate for each CRS.

https://www.usgs.gov/3dep/lidarspec https://partnerships.nationalmap.gov/arcgis/rest/services/3DEPDataAcquisition_1KMGrid/MapServer https://partnerships.nationalmap.gov/arcgis/rest/services/3DEPDataAcquisition_1KMGrid/MapServer ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/tiling_scheme

DOIGFBO200046 FY20/21 BAA Solicitation Attachment B Page 2

G20AS00104

Step 2. Buffer the AOI by 100 meters to create the Defined Project Area (DPA). The 3DEP data processing workflow requires that all project boundaries include this buffer.

Step 3. Choose or create a single nonoverlapping project tiling scheme. The tiling index must be created in the same CRS as the DPA. If the DPA does not completely fill full tiles, the tiling index must be clipped to the DPA. If the project is split into more than one subarea to accommodate multiple CRS, tiles must overlap by one column or row where the two CRS join.

DOIGFBO200046 FY20/21 BAA Solicitation Attachment B Page 3

G20AS00104

III. Instruction for Aligning with Existing Data

For project areas that are adjacent to existing lidar surveys that meet 3DEP specifications, the project boundary should align with the adjacent data before the 100m buffer is applied. The final DPA should have 100 meters of overlap with the existing neighboring lidar survey. The small amount of repeat coverage is required for 3DEP data processing workflows and also eliminates slivers and gaps between projects. The 3DEP data acquisition team will review the DPA to identify adjacent existing lidar surveys and will adjust the project boundary as needed.