31 articles Articles

Ground targets for horizontal check for LIDAR data collection

An important evaluation to make when performing a QAQC analysis of a LIDAR data set is a control point comparison. Typically, this refers to checking the vertical accuracy of a LIDAR data set. In regards to vertical check/control point location: “Unlike horizontal checkpoints, vertical checkpoints are not necessarily required to be clearly defined or readily…

Hardware recommendations for faster processing

If you’re i/o bound, which is usually the case with LIDAR or photogrammetric point cloud processing, you need to figure out what kind of i/o you’re doing at the bottleneck. Case 1: If you’re just waiting for a single tile to load, your slowdown may be from low RPM HDD, but more likely you’re hitting…

NGS Releases a New Video on the Importance of Accurate Coastal Elevation and Shoreline Data

NGS Releases New Educational Video! New Video on the Importance of Accurate Coastal Elevation and Shoreline Data This latest video explains the role of topo-bathy light detection and ranging (LIDAR) products in the National Geodetic Survey’s (NGS) mapping and charting program, and how these products provide a critical dataset for coastal resilience, coastal intelligence, and place-based conservation.  Federal,…

FEMA – Guidance for Flood Risk Analysis and Mapping – Elevation Guidance

FEMA’s elevation guidance document retires Appendix A of the Guidelines and Specifications for Flood Hazard Mapping Partners (Guidelines) and Procedure Memorandum 61 – Standards for LiDAR and Other High Quality Digital Topography, while modernizing the guidance to align with the USGS LiDAR Base Specifications v1.2, ASPRS Positional Accuracy Standards for Digital Geospatial Data (Edition 1, Version…

Best Practices for Minimizing Errors during GNSS Data Collection

Aimed at surveyors and GIS professionals who use geodetic-quality GNSS equipment to determine positions for land planning, coastal monitoring and other purposes, this video from NOAA’s video library covers best practices for reducing errors in the areas of: 1. location and environment, 2. equipment setup and 3. observation times and accuracy checks.  

Nominal Pulse Spacing (NPS)

In the LIDAR industry the generally accepted definition for Nominal Pulse Spacing (NPS) is the one detailed in the USGS base LIDAR Specification. That is the spacing between points in the collection when in reference to single instrument, single swath, first return only LIDAR point data. The NPS is a value that is usually predicted by…

Point Data Record Format (PDRF)

ASPRS (American Society for Photogrammetry and Remote Sensing) LAS Specification defines the attributed that can be stored in each point data record format (0 through 10). The chart below provides a summary as to which attributes can be stored in which format. Attribute 0 1 2 3 4 5 6 7 8 9 10 X…