As with all spatial analysis, they are subject to errors and problems from the data acquisition to the actual analysis. In this analysis, the root of almost all of the problems with the data stems from the forest stand data. Sections of forest stand in the original data were misaligned in areas where they appear to fit together. Also, parts of the forest stand, particularly the northern half, did not align too well to many of the other features used in the analysis (ie. blowdown areas, road network, trail network, lakes).
Modifications had to be made in order for the analysis to proceed. Two major modifications made to the data were the aligning of the forest stand, and the redrawing of the Stanley Park Causeway to fit the forest stand. Modifications to data results in the loss of the original data. Forest stand plots were changed so the visual area does not reflect the area in the attribute table. But because the forest stand was mainly used for its shape as a constraint, this loss of data is minimal to the analysis at hand. The redrawing of the Causeway affects the visual length of the road compared to its value in the attribute table, and it also affects the distance between the Causeway and other roads nearby. These areas between the roads would have been larger if the Causeway was not redrawn, and the area of influence by the roads would appear to be less.
In this analysis, the factors used were mainly physical influences (ie. distance from roads, distance from waterbodies, etc.). Only some aspects of Eagle behaviour were incorporated. The Stanley Park eagles prey mainly on other bird species and scavenge the seashore. The distance from the sea was incorporated into the analysis to take into account their scavenging behaviour. Eagles have a territory around their nest which they defend from other eagles. The exact territorial distance from eagle nests in Stanley Park is currently unknown, however, the Prospect Point pair of eagles have a second nest 200-300m away from their first nest. During the calculation of distances between existing nest sites, it was found that the distance between the Pipeline Road nest and the Dining Pavilion nest was approximately 700m apart, or a territorial range of approximately 350m each. Based on these two observations it was assumed, for the purpose of this anaylsis, that the territorial range for nests in Stanley Park was approximately 300-350m. This analysis would not be able to determine an exact range because more factors would have to be involved. Field observation may be a better option to determine territory ranges.
Prepared by Anthony Lau | Fall 2008 | Contact Me |