Appendix A

Contents

GIS Goals & Assumptions
GIS Sources of Data
Methodology
Results
DSL & ISM wireless potential
DTV transmitters and translators/on-channel repeaters
DTV serving non-DSL and non-ISM wireless accessible population
Analysis and caveats

GIS Goals & Assumptions

The goal of the IdahoPTV/TOP GIS analysis was to support, or debunk, a claim that IdahoPTV, as a state licensed state-wide public television network, should seek funding for a state-wide DTV datacast service on the grounds that this service is needed as a "public good"--to provide rural residents access to broadband data resources that they will otherwise not have.

· Our definition of broadband services included asymmetrical services that provided at a minimum, 200 kbps downstream.
· We recognized that satellite data services could be accessible to anyone that could afford the dish and the monthly charges, and it was unnecessary to map the physical accessibility of these services.
· We assumed that if there were proper incentives, each telephone central office could be equipped to provide DSL service to every subscriber within a three mile radius of the switching office. We used three miles, rather than 3.5 miles because cable plant seldom takes a direct path to effect a uniform radius around a switching office.
· We assumed that ISM wireless data service had a potential reach of 8 miles, provided line-of-sight. We did not include line-of-sight analysis into the calculation of the reach of the ISM wireless service. We centered the eight mile radius circle of reach at the telephone central office, assuming that this was the most efficient location for connection to the backbone.
· We assumed that within ten miles of the telephone switching office, it was reasonable to expect up to 56 kbps narrowband data service using POTS and a modem.
· Population growth in the past decade in Idaho has been predominantly in the metro areas. We assumed that the population more than three miles from a telephone switching office was basically unchanged since the 1990 census.
 

People Within State Of Idaho (1990 Census)

· Although the current IdahoPTV plan for DTV transmission does not include signal power that can uniformly reach 100 miles from any of the five transmitters in the statewide network, we assumed that potential capability.
· A 50-mile potential reach was assumed for each of the 34 translators in the IdahoPTV network.

GIS Sources of Data

Data used in the study included:
· 1990 Census data, by block and track, for Idaho
· Detailed topology of the entire state
· The location of every telephone central office within Idaho
· The precise location of the five IdahoPTV transmitters and 34 translators

Detailed bibliographic data on the sources of data is available upon request.

Methodology

ArcView software was used to do the following:
1. Three-mile, eight-mile, and ten-mile radii circles were drawn around each telephone central office in the state.
2. The population within each set of circles was calculated, based on population density within the census block or tract. Blocks, or tracts, that were only partially covered by the circles were assumed to have uniform density, and the proportion of the block, or tract, covered was applied to the total population within the individual block, or tract.
3. A line-of-sight analysis, within each 100-mile (transmitter), or 50-mile (translator) radius, was done. The population within the area identified as within line-of-sight was calculated, with the same assumption about uniform population density within block, or tract, as above.
4. Various queries were performed to identify the population that was uniquely served by translators, uniquely served by transmitters, and the population that was beyond the 3- and 8-mile radii but within the line-of-sight of the transmitters, or transmitters and translators.
5. There was some overlap of transmitter signal, so the total population was adjusted to not double-count any of the population capable of receiving a signal from more than one transmitter.

Results

· DSL and ISM wireless potential: People within each telephone switching office buffer:
 

· DTV transmitters and translators (on-channel repeaters)
 

People reached by either transmitter or translator………….

752107

People reached by any of 5 transmitters……………………..

633813

Calculated people reached uniquely by translators…………..

118294

· DTV serving non-DSL and non-ISM wireless accessible population
 

	People inside  100 mile radius, and inside telco buffer	People inside  100 mile radius and outside telco buffer	Line of Site Analysis: People within line-of-sight and outside telco buffer
Transmitters: 100 mile radius

	Total # people	3 mile	8 mile	3 mile	8 mile	Total	3 mile	8 mile
Moscow	183,857	128,361	175,902	55,496	7,955	18,909	1,784	468
Pocatello	311,786	222,797	302,342	88,989	9,444	202,166	52,732	2,588
Boise	400,428	328,062	390,870	72,366	9,558	297,155	41,745	1,929
Twin Falls	192,635	143,323	184,962	49,312	7,673	62,759	13,851	925
Coeur d'Alene	198,373	132,275	185,847	66,098	12,526	55,653	9,687	400

 

Transmitters and Translators, in Total	People able to receive DTV signal	% of people, otherwise unreached by DSL or ISM wireless	% of  1990 pop.	Est. % of 2000 pop.
People reached by either Transmitter or Translator	752107		74.7%	80.4%
…outside 3 mile telco	159682	62.9%
…outside 8 mile telco	13006	36.1%
People reached by any of 5 Transmitters	633813		62.9%	71.3%
…outside 3 mile telco buffer	119055	46.9%
…outside 8 mile telco buffer	6179	17.2%
Calculated people reached uniquely by translators	118294		11.7%	9.1%

…outside 3 mile telco

40627

16.0%

…outside 8 mile telco

6827

19.0%

Analysis and caveats

Based on the 1990 census, 253,846 people in Idaho live beyond the reach of DSL (3 miles from the nearest telephone central office). This is still a good estimate of the number of people who cannot get telco-based broadband services. In 1990, this was 25.2% of the total population in the state.

Based on 1990 census, 74.7% of the population in the state could receive the IdahoPTV signal, without cable carriage. Assuming that the population growth since then has been within the metro areas, we estimate that 80.4% of the population in the state could receive the IdahoPTV signal, without cable carriage. About 10% of the population of the state rely on IdahoPTV translators to receive a public television signal.

63.0% of the people in Idaho who cannot get DSL service COULD receive the IdahoPTV terrestrial broadcast television signal.

These statements support an argument that current, and proposed DTV, terrestrial broadcasts of public television services reach more rural people than DSL or wireless packet services can potentially reach; assuming the continuation of the translator network (or its replacement with on-channel DTV repeaters).

While the power levels at which some of the IdahoPTV transmitters and translators operate (and are proposed to operate) do not enable a 100-mile and 50-mile, respectively, potential reach at this time, it is technically possible that they could have that reach. The point of the GIS study has been to look at which broadband technology options were technically possible for the rural population of the state, given the market or public policy incentives that could encourage their deployment.

Another caveat that should be made is that the 8-mile reach of ISM wireless did not include a line-of-sight analysis. Line-of-sight is a physical requirement of the technology, but was deemed too costly for us to include in the GIS exercise at this time. Therefore, the figures estimating the population beyond the reach of ISM wireless is likely to be understated.