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measurement of a wall and rough sketch it on a pad of paper. Upon return to the office, I would then use graph paper to draft a to-scale good copy sketch and calculate the area of the structure. Unfortunately, since balance or a measurement could be written down incorrectly, sometimes the sketch would not line up. Since that time, software systems have been built that allow the user to enter lengths and directions and record the sketch electronically instead of on paper. With this electronic approach, the software provides some increased functionality to the user over pencil and paper, but can that functionality be increased? New technological evolutions in the area of sketch creation and editing have occurred using the power of a GIS. Sketch creation and edit capability in geographic space allows the ability to maintain that sketch within the coordinates (x,y) of the building's location on the earth. is allows a geo-referenced building sketch. An example of this capability is 'GeoSketch' (Figure 4), which is a geospatial editing environment that is tightly integrated with the Assessment Analyst (desktop review) system. It enables users to sketch and edit buildings and other structures directly on the map. In other words, GeoSketch is a building sketch (geometry) editor in geo-referenced space. e sketch then becomes an editable layer within the GIS, which allows enhanced visualization using the map, as well as the sharing or consumption of this layer and data between users. e layer can be integrated with additional layers of data to allow analysis, geo-processing activities or data correlations as required by the user. e key innovation of all these items such as the map, sketch, imagery, data and analytics is the fusion of disparate data sources into an integrated database with a flexible and responsive user experience driven visually from the map. e user is not constrained to a rigid series of steps, but rather is able to work with whichever information sources best illuminate the appraisal assignment for a given parcel or property. In short, the leveraging of technology into a GIS centric valuation database is about using the influence of geography to bring more information to the appraiser quickly, accurately and spatially. FIGURE 4 FIGURE 5 provide change detection analysis. Street front/oblique imagery is also integrated and used to visualize a building from many different angles. Functionality to zoom in and out of street front photos in order to get a clear look at a property and surrounding infrastructures is included in the application. Using the powerful visualization and analytics tools, users can quickly identify new construction and demolitions and conduct market segmentation, property use and market variable analysis. Using a desktop review system, the appraiser has the ability to audit, cleanse, detect and resolve existing data issues and more effectively calibrate the correct valuation. By combining the use of things like oblique imagery into the workflow, users can conduct measurements and make corrections to the corresponding building sketch, adjust line work on the building sketch and have the changes populate the database. rough sketch verification, building sketches can be compared with aerial photography to check for anomalies and spot new construction or other changes that could be constructed without a permit. Where does data creation start? In real estate valuation, the appraiser often requires a starting point of data and, more often than not, the process begins with defining and validating the area (square feet/meters) of the building(s). is brings us to evolutions in building sketching technology. When I first started doing appraisals, I measured buildings on site using a clipboard and pencil. I would take the Canadian Proper ty Valuation | Évaluation Immobilière au Canada | Volume 59 | Book 3 / Tome 3 | 2015

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