Proposed GIS Project for West Boylston

Sitemap

What Is GIS?

GIS stands for Geographical Information System. A GIS is essentially a database used for creating maps. However, when used in conjunction with GIS software, it is really much more than "just" mapping software. Using GIS data, you can:

In addition to the host of environmental and scientific applications GIS has, it could be extremely useful for historical applications. Digitizing and georeferencing old maps could show interesting trends in:

Like a number of small towns across during the 20th century, West Boylston, Massachusetts was forced to rebuild itself when the Metropolitan District Commission decreed in the late 1800s that parts of the town (and neighboring Boylston, Sterling and Clinton) would have to be taken for a reservoir for Boston and the rest of eastern Massachusetts.

When you decide to start a GIS project, the first thing you need to do is to develop a question that manipulating GIS data will answer. To do a GIS project on the historical impact of the Wachusett Reservoir on West Boylston, we could ask the following question:

Where are the streets that existed in West Boylston, MA in 1892, relative to the Wachusett Reservoir that was built in the center of town in 1906?

Data Coverages

The state of Massachusetts has an extensive set of modern data coverages at http://www.state.ma.us/mgis/massgis.htm. However, it has little in the way of antique maps and no historic data coverages. For a real project, the 1855 map would be digitized and completely georeferenced (while many of the roads in West Boylston have moved over the years, one set of train tracks are in the same location now that they were 150 years ago, so there is at least some basis for comparison). There is a good topological map from 1892 that would be digitized and georeferenced to show the "before the reservoir" elevations in the area.

Description of the Project Data

Coverage Name Feature Types Contents
topo1892 Polygons Defines elevations, tics and study area from the 1892 topographic map
roads1855 Arcs Defines and codes all roads and train tracks from the 1855 town map.
streams1855 Arcs Identifies all streams from the 1855 town map
wtrshds1855 Polygons Identifies ponds from the 1855 town map
roads1992 Arcs Defines and codes all roads and train tracks from the 1992 Massachusetts GIS Web Site.
streams1992 Arcs Identifies all streams from the 1992 Massachusetts GIS Web Site.
wtrshds1992 Polygons Identifies all streams, reservoirs and ponds from the1992 Massachusetts GIS Web Site.

As the three coverages were based on maps created at different times, they undoubtably have different scales and projections. Great care would need to be taken to be sure the data is correct and the same units are in force across the databases before merging any of the data.

Coverage Description and Data Layer Dictionaries

topo1892

Item definitions for topo1892.aat

Elevation data

Calculated locations of TICs

roads1855 -- Item definitions for roads1855.aat

Column Item Name Width Output Type N. Dec
1 FNODE# 4 5 B --
5 FNODE# 4 5 B --
9 LPOLY# 4 5 B --
13 RPOLY# 4 5 B --
17 LENGTH 4 12 F 3
21 ROADS8# 4 5 B --
25 ROADS-ID8# 4 5 B --
29 RD-CODE8 1 1 I --

roads1855.lut

Column Item Name Width Output Type N. Dec
1 RD-CODE8 1 1 I --
2 LABEL 20 20 C --
21 SYMBOL 3 3 I --

The look-up table would differentiate the railroad tracks from roads. If the code is 1, it's a road, and if the code is 2, it's train tracks and would have a different symbol on the map.

streams1855 -- Item definitions for streams1855.aat

Column Item Name Width Output Type N. Dec
1 FNODE# 4 5 B --
5 FNODE# 4 5 B --
9 LPOLY# 4 5 B --
13 RPOLY# 4 5 B --
17 LENGTH 4 12 F 3
21 STREAMS# 4 5 B --
25 STREAMS-ID8# 4 5 B --

wtrshds1855 -- Item definitions for wtrshds1855.aat

Column Item Name Width Output Type N. Dec
1 AREA 4 12 F 3
5 PERIMETER 4 12 F 3
9 WATER-ID8 4 5 B --

roads1992 (based on data from the Massachusetts GIS site)

Item definitions for roads1992.aat

Column Item Name Width Output Type N. Dec
1 FNODE# 4 5 B --
5 FNODE# 4 5 B --
9 LPOLY# 4 5 B --
13 RPOLY# 4 5 B --
17 LENGTH 4 12 F 3
21 ROADS# 4 5 B --
25 ROADS-ID# 4 5 B --
29 RD-CODE9 1 1 I --
30 RDLABEL9 20 20 C --

roads1992.lut

Column Item Name Width Output Type N. Dec
1 RD-CODE9 1 1 I --
2 LABEL 20 20 C --
21 SYMBOL 3 3 I --

These are essentially the same tables as for roads1892 except some attribute names are slightly different so that when the datasets are merged, values are not overwritten.

streams1992 (data from the Massachusetts GIS site)

Item definitions for streams1992.aat

Column Item Name Width Output Type N. Dec
1 FNODE# 4 5 B --
5 FNODE# 4 5 B --
9 LPOLY# 4 5 B --
13 RPOLY# 4 5 B --
17 LENGTH 4 12 F 3
21 STREAMS# 4 5 B --
25 STREAMS-ID9# 4 5 B --

wtrshds1992 (based on Map 2) -- Item definitions for wtrshds1855.aat

Column Item Name Width Output Type N. Dec
1 AREA 4 12 F 3
5 PERIMETER 4 12 F 3
9 WATER-ID9 4 5 B --

Coverages and Spatial Operations

Selection Criteria Data Layers Suitable Areas Spatial Model
Elevation info from the 1892 map Elevation information topo1892 buffer1892
Road and railroads in central West Boylston, 1855 Layer showing roads and railroads in 1892 roads1855 buffer1855
Streams in central West Boylston, 1855 Layer showing streams in 1855 streams1855
Ponds in central West Boylston, 1855 Layer showing ponds in 1855 wtrshds1855
Road and railroads in central West Boylston, 1992 Layer showing town road and railroads in 1992 roads1992 buffer1992
Streams in central West Boylston, 1992 Layer showing streams in 1992 streams1922
Reservoir and ponds in central West Boylston, 1992 Layer showing pond and reservoir boundaries in 1992 wtrshds1992
finalcov

If GIS data generated from older maps were properly merged, the final map would look something like this:

superimposed streets Current view of West Boylston with streets from 1855 roughly located in pink, courtesy of Massachusetts Geographic Information System (MassGIS)

Partial 1855 street layout added by Laurie Trask Mann