Name: Tree_Canopy_2018_2020_Chg_Py

Display Field: CLASS_NAME

Type: Feature Layer

Geometry Type: esriGeometryPolygon

Description: This layer is a high-resolution tree canopy change-detection layer for Prince George's County, Maryland. It contains three tree-canopy classes for the period 2018-2020: (1) No Change; (2) Gain; and (3) Loss. It was created by extracting tree canopy from existing high-resolution land-cover maps for 2018 and 2020 and then comparing the mapped trees directly. Tree canopy that existed during both time periods was assigned to the No Change category while trees removed by development, storms, or disease were assigned to the Loss class. Trees planted during the interval were assigned to the Gain category, as were the edges of existing trees that expanded noticeably. Direct comparison was possible because both the 2018 and 2020 maps were created using object-based image analysis (OBIA) and included similar source datasets (LiDAR-derived surface models, multispectral imagery, and thematic GIS inputs). OBIA systems work by grouping pixels into meaningful objects based on their spectral and spatial properties, while taking into account boundaries imposed by existing vector datasets. Within the OBIA environment a rule-based expert system was designed to effectively mimic the process of manual image analysis by incorporating the elements of image interpretation (color/tone, texture, pattern, location, size, and shape) into the classification process. A series of morphological procedures were employed to insure that the end product is both accurate and cartographically pleasing. No accuracy assessment was conducted, but the dataset will be subjected to manual review and correction.

Service Item Id: 1fc5eeeed72f4333b8ad38c90c04ff81

Copyright Text: University of Vermont Spatial Analysis Laboratory and Sanborn Map Company in collaboration with Prince George's Tree Canopy Change Assessment.

Default Visibility: true

MaxRecordCount: 2000

Supported Query Formats: JSON, geoJSON, PBF

Min Scale: 0

Max Scale: 0

Supports Advanced Queries: true

Supports Statistics: true

Has Labels: false

Can Modify Layer: true

Can Scale Symbols: false

Use Standardized Queries: true

Supports Datum Transformation: true

Extent:

XMin: NaN
YMin: NaN
XMax: NaN
YMax: NaN
Spatial Reference: 102685  (2248)

Drawing Info:

Renderer:
Simple Renderer:
Symbol:
Style: esriSFSSolid
Color: [215, 234, 183, 255]
Outline:
N/A
Label: N/A
Description: N/A
Transparency: 0
Labeling Info:

Advanced Query Capabilities:

Supports Statistics: true
Supports OrderBy: true
Supports Distinct: true
Supports Pagination: true
Supports TrueCurve: true
Supports Returning Query Extent: true
Supports Query With Distance: true
Supports Sql Expression: true
Supports Query With ResultType: false
Supports Returning Geometry Centroid: false
Supports Binning LOD: false
Supports Query With LOD Spatial Reference: false
Supports Percentile Statistics: true
Supports Having Clause: true
Supports Count Distinct: true
Supports Time Relation: true
Supports Sql Format: false
Supports Query Analytic: true
Supports Query With Current User: true

HasZ: false

HasM: false

Has Attachments: false

HTML Popup Type: esriServerHTMLPopupTypeAsHTMLText

Type ID Field: null

Fields:

• OBJECTID ( type: esriFieldTypeOID, alias: OBJECTID )
• CLASS_NAME ( type: esriFieldTypeString, alias: CLASS_NAME, length: 10 )
• Shape ( type: esriFieldTypeGeometry, alias: Shape )
• Shape.STArea() ( type: esriFieldTypeDouble, alias: Shape.STArea() )
• Shape.STLength() ( type: esriFieldTypeDouble, alias: Shape.STLength() )

Supported Operations:   Query   Query Attachments   Query Analytic   Generate Renderer   Return Updates

  Iteminfo   Thumbnail   Metadata