Abstract
Utility companies must consider the following to arrive at the appropriate technical specifications for their GIS data and the corresponding implementation schedule:
- Impact of technology on the cost of data acquisition: All the technologies required for acquiring data of appropriate quality are already in place. Technology is unlikely to make any major contribution to reduce the cost of data acquisition in the foreseeable future. This will be more true for compilation of large scale maps (which we will call "Fine Mapping Product" in rest of this document).
- Impact of maturity of GIS data vending industry: In the next few years, maturity of the data vending industry will drive down the price of GIS data and simultaneously increase the data quality
- Impact of better and cheaper GIS software: Some of the upcoming GIS software are much more elegantly built and are so much cheaper. Hence, GIS computing will become much more commonplace and GIS database can afford to be more elaborate.
- Cost of upgrading the landbase at a future date: Utility companies which presently start with less sophisticated land base are likely to face high upgrade and migration cost in the future.
- When the above are taken into
consideration, it shows that the optimal specification for the
Geographical Information System and their implementation plan must
be different from what is prevailing in the Indian industry.
Limitations
The discussions of this paper have two application limitations:
- The paper discusses the Utility GIS in the context of city based utility services only. Content of this paper will require substantial modifications to accommodate cross-country utility infrastructure like high tension power distribution
- The paper is tailor made for developing
countries like India. In most of the developed countries, GIS data
of high quality are readily available at a fraction of the data
acquisition cost.
Components of GIS Data
All GIS data are made of two components:
- Geometry of geographical features like locality boundary, street boundary, plot boundary, building features, etc. These type of data are called the "geometric data". An illustration showing a typical geometric data for an Utility GIs is enclosed in the illustration overleaf.
- Information associated with the geometric
data like locality name, street name, nature of occupation of a
plot, elevations, etc. We will call this the "attribute data"
Following are the typical "Geometric Data" are generally required in an Utility GIS
Following are the typical "Geometric Data" are generally required in an Utility GIS:
- Right of Way Edge
- Average Road Width
- Right of Way Center
- Carriage Way Edge
- Carriage Way Center
- Median, Traffic Island
- Property Boundaries
- Entrances to Properties
- Power and Telecom Poles, Pylons, Junction Boxes, Transformers, etc.
- Overhead Power and Telecom Cables
- Buried Power and Telecom Cables
- Manholes
- Underground sewerage and water supply lines
- Locality, Sub-Locality and PIN Code
Boundaries
The geometric data is usually acquired with one of the following two accuracies:
| |
Positional Accuracy |
Geometric Tolerance |
Coarse Mapping
Fine Mapping |
10m (using hand held DGPS or IKONOS)
2m (using Geodetic
GPS and ETS) |
1-2m (using Rodometer and Tape)
Sub-decimeter (using
ETS) |
Due to the inherent nature of the technologies deployed,
- "Fine Mapping" is much more capital intensive than "Coarse Mapping".
- "Fine Mapping" is more labor intensive than "Coarse Mapping".
- Hence, "Fine Mapping" is usually two to
three times as expensive as "Coarse Mapping".
World over, it is the general practice to use "Coarse Mapping" specifications at the planning stage.
Whereas, India seem to stand divided in usage of "Fine Mapping" specifications. Even though labor cost is much higher in developed countries, which should make the "Fine" products much more expensive there , developed countries seem to go for the "Fine" product for utility maintenance and operations. However, in India, where utilities are just beginning to adopt to GIS, even though the "Fine" product is "only" about two times as expensive as "Coarse" product, there is a tendency to use the "Coarse" product for operations and maintenance as well.
Addressing this anomaly adequately will create/save economic value running into tens of crores of Rupees in the country within the next few of years.