Originator: Spatial Analysis Unit, Carolina Population Center
Publication_Date: 2000
Title: North ISA Terrain Aspect
Geospatial_Data_Presentation_Form: raster digital data
Description:
Abstract:
This data set contains the terrain aspect for the Northern Intensive Study Area (ISA) of the CPC Ecuador Projects, in the northern Oriente of Ecuador. Aspect is the downslope direction of the maximum rate of change on a hillside. It is derived from a digital elevation model (DEM). Each pixel is attributed with a value that represents the compass direction, in degrees clockwise from 0 at north, in which the hillside faces. The raster resolution of the data set is based on the resolution of the source DEM – in this case, 30 meters.
Purpose:
The aspect data can be used for any analyses that require a directional terrain component, or for simple three-dimensional representation of the ISA.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 1993
Currentness_Reference: publication date
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -76.752607
East_Bounding_Coordinate: -76.501410
North_Bounding_Coordinate: -0.002758
South_Bounding_Coordinate: -0.337303
Keywords:
Theme:
Theme_Keyword_Thesaurus: Ecuador
Theme_Keyword: terrain
Theme_Keyword: aspect
Theme_Keyword: hillside
Theme_Keyword: direction
Access_Constraints:
Data is available to the public, made possible through the NASA LBA program.
Use_Constraints:
There are no use constraints. However, potential users should be aware that the resolution of this data set makes it inappropriate for any analyses where the scale of analysis is finer than 30 meters.
The aspect data was generated by Brian Frizzelle, of the Spatial Analysis Unit, Carolina Population Center.
Security_Information:
Security_Classification: Unclassified
Native_Data_Set_Environment:
Microsoft Windows NT Version 4.0 (Build 1381) Service Pack 6; ESRI ArcCatalog 8.2.0.700
Cross_Reference:
Citation_Information:
Title: North ISA Digital Elevation Model
Cross_Reference:
Citation_Information:
Title: North ISA Terrain Slope
Cross_Reference:
Citation_Information:
Title: East ISA Terrain Aspect
Cross_Reference:
Citation_Information:
Title: South ISA Terrain Aspect
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
The directional aspect values assigned to the pixels in the data set were generated with the ASPECT algorithm in ARC/INFO, which calculates the direction of greatest elevational change based on surrounding pixels. Aspect values are derived solely from the DEM data. An accuracy assessment of the aspect values has not been performed.
Completeness_Report: Data are complete for the ISA.
Lineage:
Process_Step:
Process_Description:
The North ISA Digital Elevation Model was used to generate the aspect surface. The ASPECT command in ARC/INFO was used. For each pixel, ASPECT calculates the direction of the greatest rate of elevational change in the surrounding pixels and assigns that value to the pixel.
The pixels are attributed with the aspect direction, in degrees. The directions range from 0 to 359, increasing in a clockwise direction from north, which has the value of 0.
