Digital Tax Parcel Mapping - Advantages and Limitations
The major advantage of digital maps is their versatility: digital tax maps can be viewed and printed at any scale and customized with different labels to suit different purposes.
A combination of numerical, textual and visual (e.g. digital photos of properties including buildings) can be embedded into the system and retrieved based on numerous spatial or statistical selection criteria.
Digital maps can be maintained and updated much faster than paper maps.
Digital maps require limited physical storage space and can be easily electronically backed up and protected against data losses (a serious problem in many tax administration offices is the lack of office space and safe map storage facilities).
Digital tax maps can be easily overlaid with other information layers such as land use planning zones, new road openings, building footprints or physical terrain features. This allows the performance of different analysis and planning tasks within a local government unit. The integration of digital tax parcel data into a multi-purpose Land Information Systems (LIS) can create a versatile spatial planning and management system. The costs and benefits for establishing and maintaining such a system can be shared by different sections of the local administration.
Costs of using high resolution satellite images to overlay digital municipal base maps are rapidly decreasing.
Data and maps can be made accessible through inter and intra-net and can be easily shared in an electronic working environment.
Transparency of local direct taxation can be enhanced.
A condition for efficient tax collection is the computerization of the tax data management. The additional costs in digitizing tax parcel information must also be compared with the benefits arising from the digitized maps: For tax purposes, digital tax parcel maps is a ‘nice to have’, but it’s not a “must”.
Information technology and GIS technologies incur recurrent costs for training, upgrading and hiring of qualified staff. This necessitates that these costs are integrated into annual budgets.
Building an integrated multi-purpose Land Information Systems (LIS) incorporating a digital parcel data layer depends on adequate geographic base map data (cadastral survey, geographic coordinates of public infrastructure) that have a high resolution.
If the manually drawn paper tax maps of the assessor lack a minimum of geographic accuracy (for example because they are not be based on up to date cadastral survey maps), it is difficult or even impossible to assemble a matching mosaic of different tax maps sections. This necessitates that a time and resource intensive GPS ground-verification survey is undertaken.