For the Clark County vegetation mapping project, CTI used a combination of image processing, segmentation, and photo-interpretation. This “hybrid” approach involves two stages (coarse and fine level mapping) and has proven to be the most cost-effective means of creating an accurate vegetation layer for large and complex environments. The coarse level map units correspond to the USNVC Group level. The base imagery included mostly 2019 NAIP imagery with some area utilizing the October 2019 Pleiades satellite constellation to fill in areas that were not covered by the NAIP imagery program.

The coarse level mapping utilized existing linear features from previous mapping efforts will be used (as warranted) to maximize efficiency and maintain consistency with existing and neighboring vegetation layers. The coarse level mapping used custom image processing routines from CTI to create a network of lines that match general vegetation features. CTI delineated physiognomic patterns and any other obvious landscape features (e.g. large barren or homogeneous areas). This stage of mapping split the mapping area into defined landforms and delineated the complex network of drainages and washes. The results of the coarse-level mapping will be reviewed and any missing or inaccurate areas will be identified and re-processed. CTI will consider the coarse level mapping complete when all Group level boundaries are consistent with the basemap imagery.

Verification work consisted of eight field days collecting 63 observations, augmented by over 1,000 previous observations throughout Clark County by USGS. Staff for the verification trips consisted of either a single botanist or one botanist and an assistant. CTI verified the draft map in the field by identifying the vegetation on the ground at selected sites.

No accuracy assessment has been completed for this product.