CWD Geographic Information Systems 3

Question 1

Which USGS topographic map scale provides sufficient detail for most project-level wetland delineations?

Accepted Answer

1:24,000

Answer

The 1:24,000 scale (7.5-minute quadrangle) is the standard USGS topographic map series used for project-level field work and wetland delineations.

Question 2

In GIS, a 'spatial join' is used in wetland analysis to:

Accepted Answer

Attach attributes from one layer to features of another based on location

Answer

A spatial join transfers attribute data from a source layer to a target layer based on spatial relationships, allowing wetland features to inherit attributes like soil type or land use.

Question 3

The National Wetlands Inventory (NWI) uses the Cowardin classification system. In GIS, NWI data is delivered as which file format?

Accepted Answer

Shapefile or geodatabase feature class

Answer

NWI data from the U.S. Fish and Wildlife Service is distributed as vector shapefiles or geodatabase feature classes representing wetland polygons with Cowardin classification attributes.

Question 4

A delineator uses a DEM to calculate flow accumulation. What does a high flow accumulation value at a location indicate?

Accepted Answer

Many upslope cells drain through that location, suggesting a potential drainage way or wetland

Answer

High flow accumulation values indicate that a large number of upslope grid cells contribute runoff through that point, identifying potential stream channels and wet areas.

Question 5

Which metadata element is most critical to record when incorporating a GIS wetland data layer into a delineation report?

Accepted Answer

Data source, publication date, spatial accuracy, and coordinate system

Answer

Data source, date, accuracy, and coordinate system are essential metadata for evaluating data reliability and ensuring regulatory defensibility of the delineation.

(CWD) Certified Wetland Delineator Practice Test

(CWD) Certified Wetland Delineator Practice Test

CWD Geographic Information Systems 3