Micropath Corporation - The beginning and a brief history of path profiles and
digital elevation data
In 1983 Rocky Mountain Microwave began developing microwave path design software to
generate path profiles and link analysis calculations.
A few years later we did a name change to Rocky Mountain Communications since predicted area coverage (PAC) software was developed in order to support
VHF/UHF repeater systems. In 1992 another name changed occured and Micropath
Prior to the introduction of digitial elevation models (DEMs) in the 1980's,
creating a path profile was sometimes a laborious process depending on the
length of the path. One had to manually extract elevation points from USGS
7.5' topographic maps and calculate distances of each point from the starting
point. Path profiles were plotted on graph paper or special earth
curvature graph paper. Topo maps were laid out on the floor and a string
or board was used to draw a straight line from Site A to Site B. More path
profiling sophistication evolved by developing an algorithm to calculate the
7.5' map latitude / longitude crossover points. Maps were then placed on a
drafting table and the straight line of the path was drawn between map edges or
from the map edge to Site A or Site B.
In the early 1980's, 30-second
elevation data became available through a dial-up path
profile service provided by the National Telecommunications and Information
Administration (NTIA) in Boulder, Colorado. The horizontal resolution
(approx 3003 feet) and the vertical accuracy of the DEMS were far from perfect
but did provide a quick look at a proposed radio communications path.
During these years computer technology for the end user was rapidly developing
with terminals, PC's, and graphing plotters. By 1984 path profiles were
being plotted on equipment such as the HP7475A and HP7476 plotters - provided
someone wrote the software. Fortran, Basic, and C were the programming
Circa 1990 3-second DEMs were being produced and sold by the USGS. Source
of the 3-second data was the 1:250,000 scale USGS topomaps. The data was
delivered on 9-track tapes. The original USGS 3-second data provided new
insights into digital path profiling but the 303-feet horizontal resolution and
vertical accuracy of the elevations (1:250,000 scale maps) was not perfect.
Critical points along the path still had to be verified against the 7.5'
By 1994 the 7.5' 30-meter DEMs were produced and sold by USGS. There were
approximately 66,000 7.5' DEM files for the United States. 30-meter DEM coverage
was good but there were occasional holes or gaps in the data coverage,
especially in New York and New Mexico. USGS was now producing the 10-meter DEMs
but only for selected areas and to fill in the missing 30-meter DEMs. By 2000
there may have been about 12,000 10-meter DEMs produced in relation to 66,000+
30-meter DEMs. Fortunately, a higher degree of confidence in the accuracy
of digitally produced path profiles came with the use of the 10/30-meter DEMs.
Around the year 2000 USGS introduced the 1-arc second National Elevation Dataset
(NED). NED was a seamless dataset that spanned the USA. NEDs were produced
from the best available data, i.e., mainly from the NAD27 10/30-meter DEMS.
The 10/30-meter DEMS were reprojected to NAD83 (WGS84). NED 1, 1/3, and
1/9 arc-second data are available in the public domain.
Also during this time the Space Shuttle mapped the earth and the SRTM 3-second
elevation data become available for most of the world. SRTM 1-second data for
the USA was also produced.
Google has become a recent entry into the world of digital elevation data.
Although Google doesn't provide any information about the source of their
digital elevation data it is believed the Google Elevation Data Service
incorporates the best available data into their elevation data product.
Coverage is worldwide.
It's been a long journey since we sold our first program in 1984. Program
design has radically changed with an emphasis now on intuitive and a user
friendly interface, minimize or replace keyboard data entry with mouse click
functionality, and mapping ! Currently we have developed in our newer
releases of software an interface that dwells heavily with real time mapping and
earth visualization features and functionality. Program navigation
revolves around tabs while various program values and settings are presented as
properties which eliminates or in some instances reduce the amount of redundant
mouse clicks, manual keyboard entries, and program navigation hopping from one menu to another and
then back again. We are optimistic that our "Visual Path Design Software"
products are designed and function well for you accordingly.