Management and Use of Management and Use of LiDAR-Derived InformationLiDAR-Derived Information

Elizabeth CookElizabeth CookUSDA-NRCSUSDA-NRCS

Columbia, MOColumbia, MO

Now What?

Study Area

Project DeliverablesLAS mass point files, all returns, with and without breaklines, qq quad tiles1-m ESRI Grid bare earth DEM files, quad and qq quad tiles1-foot pixel natural color digital orthophotos in geotiff, ecw and sid formats (collected with LiDAR and used for breakline mapping)Independent control points for QAMisc shapefiles – tile indexes, breaklines

Data Management – File SizesTotal for 4-county

project area

Grid DEMs 31.4 gbLAS 92 gbImagery 261.2 gb

(one format or version of the data)

One 7.5-minute quad

Grid DEM – 585 mbLAS 1.8 gbImagery 4.6 gb

Data Management – Formats, Areas of Coverage, Products

Method 1 – deliver “raw” data, such as LAS, ASCII mass point files or ESRI terrains; users clip to areas of interest and process derivativesMethod 2 – deliver tiles of derivatives according to anticipated users needsMethod 3 – deliver some derivatives, but customize as necessary, and let high-end users process their own

Data Formats – “Raw”LAS – industry standard binary file of x,y,z,i (and more) data

not many softwares read (changing fast)may want to generalize, sample per class, etc

ASCII x,y,zlarge and slow

ESRI Terrain – multi-resolution database object that “stages” the data for subset, generalization and derivatives

requires knowledgeable userslots of time to create

Terrain visualized as a TIN;resolution based on scale of display and pyramid levelsof terrain

Derivative Data from LiDAR

Digital Elevation Model (bare-earth raster)Digital Surface Model (with canopy)HillshadeTIN – ESRI vs. CADContoursAll are 2-D representations of terrain

Applications to Conservation Planning

•LiDAR data can speed design time by eliminating much of the field survey.

•This dam was designed in 15 minutes without ever going to the field.

Improving Soil Map Unit Boundaries

Standard 10m DEM from hypsography

1m LiDAR

Flooding Frequency Interp.Soils

Using LiDAR First Returns

1. Extract first return LiDAR points2. Low-pass filter to generalize3. Polygonize for forest/non-forest layer

(red mask)

Helping People Help the LandHelping People Help the Land

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