Search
Browse by Subject
Contact Information

Northern Research Station
One Gifford Pinchot Drive
Madison, WI 53726
(608) 231-9318
(608) 231-9544 TTY/TDD

Urban Natural Resources Stewardship

Urban Tree Canopy Assessment Data Requirements

The UTC assessment protocols were designed to take advantage of the high resolution geospatial datasets that are the standard for most communities.  During a UTC assessment high resolution land cover is integrated with planitmetric datasets, such as buildings and roads to determine the Existing UTC and Possible UTC.  The UTC metrics can then be summarized using cadastral and boundary datasets consisting of rights of way (ROW), property parcels, and target geographies.  Target geographies are boundary datasets such as wards, neighborhoods, census blocks, zoning districts, etc.

Most communities have high resolution building footprints, road polygons, parcels, public rights-of-way and target geographies (neighborhoods, census blocks, etc.) in their GIS database.  Less common is the high resolution land cover that serves as the basis for most of the UTC assessment.  Manual interpretation of remotely sensed data is too timely and costly.  Fortunately advances in automated feature extraction make deriving land cover information from high resolution remotely sensed datasets cost effective.

UTC Data Layers

DESCRIPTIONS   PURPOSE
BUILDINGS
Building footprints consisting of unique polygons for each structure. Buildings layer Building footprints are used to exclude land occupied by buildings from the Possible UTC metrics.
ROADS
Polygons delineating the boundaries of the road at the curb edge. Sometimes referred to as “road casings.” Roads layer
  • Summarize Existing UTC overhanging roads
  • Possible UTC estimate exclude road polygons
ROW
Polygon boundaries for the Rights-of-Way. This typically consists of all non-parcel land, excluding water. Public Right of Way
  • Existing UTC summary for ROW
  • Possible UTC estimate for ROW
IMAGERY
High-resolution multispectral imagery.
Specifications: leaf-on, color infrared, uncompressed format.
Orthophotos

Leaf-on multispectral imagery is used to derive land cover. If the imagery has not been orthorectified, a digital elevation model (DEM) will be required along with existing orthophotos to extract ground control points.

PARCELS
Property parcel boundaries. Attributes should include a unique parcel ID and the land use type. Property Parcel Boundaries

UTC metrics are summarized at the parcel level. Land use attributes are used to determine the land use with the most tree canopy and the land use with the most room for establishing tree canopy.

GEOGRAPHIES
Geographical polygon boundaries by which to summarize the data, such as neighborhoods or districts. Each separate polygon must have a unique ID. Multiple layers may be submitted. Geographical Polygon Boundaries

In addition to summarizing the UTC metrics at the parcel level, the UTC metrics are summarized by other areas of interest.

LIDAR
Bare earth and first return data in raster, vector, ASCII or LAS format. LIDAR Imagery

Although not required the availability of LiDAR decreases the cost of deriving land cover data in addition to improving the accuracy of land over mapping. LiDAR data can also be used to assess the structure of the urban forest.

 

Last Modified: 06/27/2019