Finding Ontario Base Maps in the Geospatial Centre

The Ontario Base Map (OBM) series provides general-purpose topographic map coverage of Ontario. These maps depict ground relief, drainage, buildings, roads, railways, and other physical and cultural features.

Southern Ontario is covered completely at a scale of 1:10,000, and Northern Ontario at a scale of 1:20,000. The library has paper and microfiche copies of these maps for the Region of Waterloo, ranging in date from 1982-1985. The OBM paper series has been discontinued and replaced with the digital NRVIS (National Resources and Values Information System) data as well as a pdf version.

You will need to use index maps to locate specific OBMs. This publication is a guide to using index maps to locate OBMs in paper and microfiche format. Further information and assistance is available from staff at the Map Library's Public Services Desk.

Step 1: locate the index map

There are 22 index maps for Ontario.  Index maps for paper and microfiche format are stored on the text shelf. Additional copies of the index maps with the Geospatial Centre's holdings highlighted on them are kept with the OBMs in the horizontal map cabinets (G3460 svar.O5x).

Step 2: determine the map number

Use the appropriate index map and locate your area on the map. Library holdings are highlighted in yellow. If your area is not shaded in then please consult staff at the Services Desk for possible digital access.

The black grid superimposed over the index map marks the borders of each map. The 2 digit number in the left corner of the grid square is the year that the map was published. A symbol in the right corner of the grid square indicates that digital data is available. Area names are highlighted in colour if 1:2,000 maps are available from that particular municipality.

Map numbers are a composite of scale, grid zone, easting, and northing.

SCALE:

If the area is shaded in orange, the scale of the map is 1:10,000; green shading indicates that the scale of the map is 1:20,000. Write down either 10 for 1:10,000 or 20 for 1:20,000 as the first part of your map number.

GRID ZONE:

Use the figure on page 1 to determine in which of the 4 zones (15, 16, 17, or 18) your map is located. Zones 15, 16, 17 or 18, shown at the top of the figure, are the second part of your map number.

EASTING:

Locate the bottom left corner of the grid square outlining the map you wish to consult. Follow the border of this grid square to the top or bottom margin of the index map. The 4 digit number is the EASTING, the third part of your map number.

NORTHING:

Locate the bottom left corner of the grid square outlining the map you wish to consult. Follow the border of this grid square to the left or right side of the index map. The 5 digit number is your NORTHING.

 

Microfiche are also assigned grid coordinates, made up of a letter and a number. A green grid, superimposed over the index map, outlines the borders of each microfiche. To determine the grid coordinate for the microfiche you wish to consult, follow the border to the top and right margins of the index map.

Step 3: find the specific map in the collection

OBMs in paper format are filed by map number in the horizontal map cabinets (G3460 svar.O5x). The map numbers are listed at the bottom and top right corner of each map. The edition of the map is listed at the bottom of the map. Adjoining map numbers to your map will be shown in the bottom right corner of your map.

Circulation and copying

Unless stamped "for use in the library only," OBMs in paper format circulate for 2 weeks with 1 renewal. Maps designated "for use in the library" only may be borrowed for a short period of time (3 hours) to be copied.

When you are finished using the OBMS

Please do not refile any materials. Leave the maps on the tables or on top of the map cabinets. Microfiche must be returned to the Public Services Desk.