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The analysis that I decided to do included both Boolean multi-criteria evaluation and weighted linear combination to investigate the best possible locations for housing identification developments. I wished to do these two forms of spatial analysis in order to compare the end results, and determine which analysis accomplishes the best results. Both methods involved rasterizing vector data, exporting attribute values files to form new images, distance operations and reclassing. I completed the Boolean multi-criteria evaluation first and then compared it to the weighted linear combination.
Layers Used
zoning.vct
parks.vct
creeks.vct
from DNV
STREETS_SHP
Boolean Multi-criteria Evaluation
In preparation for the Boolean multi-criteria evaluation, I had to decide what was going to be considered as the factors and constraints of my analysis. Based upon the data that I had, as well as the common criteria for sustainable development in cities, the area for development would have to be within a development zone, close or adjacent to multiresidential zones, within 1km of an elementary school, within 500m of a park, more than 2km away from an industrial zone, and more than 100m from creeks. I was unable to find the specific bylaws concerning the required distance a building must be from creeks. As a result I guessed what an appropriate distance would be. In this case I chose 100m as the buffer zone required for development. I chose to look at development zones near to multiresidential zones in an attempt to maintain the character of the community as much as possible. Having an elementary school within walking distance from a development will encourage families to move into the area. It has also been stated that green space is extremely important to denser developments. Each unit does not necessarily receive any private green space and therefore it is very important that the residents have access to public green space where they can go to relax and enjoy the outdoors without having to travel a great distance. It should be similar to having a backyard. And lastly, I chose to distance any development more than 2km form industrial zones to maximize aesthetic and heath considerations.
I decided to use the zoning data from the SIS drive as the base map for my analysis. In order to find out what the various zoning categories are, I examined the database within the database workshop to identify what information was given. The zoning categories were separated into eight major groups with several subgroups within them. The Eight main categories were: MULTIRESIDENTIAL, SINGLE-FAMILY RESIDENTIAL, INDUSTRIAL, NULL, PARKS AND PROTECTED AREAS, PUBLIC ASSEMBLY, COMMERCIAL, AND COMPREHENSIVE DEVELOPMENT.
Steps
From the ZONING
image, I created vector images of multiresidential zones, development zones,
null zones, and industrial zones
From the distance and cost surfaces, I was able
to create Boolean images of each of the criteria.
The parameters for RECLASS were:
Parks | within 500m |
Industrial Zones | >2km away |
Elementary Schools | within 1km |
Creeks | >100m away |
Multiresidential Zones | within 1m |
The resulting Boolean images were then used in
a Boolean multi-criteria evaluation to produce the final image showing
the best locations for dense housing development.
For this process I needed to create distance surfaces of all images and then perform the FUZZY decision support operation upon them to create a more transitional zone around each of the criteria to take into account those areas very near the parameters.
In order to proceed with this analysis, I was
required to create a raster image of the complete zones of DNV. TO
do this I reexamined the database and created the field CLASS_ID.
I then exported this field as an attribute values file and assigned this
to the previously created ZONINGRAS
to create the image ZONERASDB
I divided the the criteria into factors and constraints.
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INDUSTDISTBOOL | MULTIFUZZ |
CREEKDISTBOOL | PARKFUZZ |
ZONEFUZZ | ELEMFUZZ |
In the creation of ZONEFUZZ, I assigned Development Zones a value of 255 and Null Zones a value of 200 to indicate that development zones are perfect sites for building upon, but there is also potential to gain permission to develop on areas that currently are not zoned for anything specific. All other zones were given a value of zero indicating that they are not to be considered.
Weight Calculation
ELEMFUZZ | 1 | ||
MULTIFUZZ | 7 | 1 | |
PARKFUZZ | 3 | 1/5 | 1 |
Resulting Weights
ELEMFUZZ | 0.0810 |
MULTIFUZZ | 0.7306 |
PARKFUZZ | 0.1884 |
In order to analyze the factors, taking into consideration the constraints, I performed a weighted linear combination of the criteria. The resulting image designated sites that were best suited to the purpose of denser housing developments.