BOT 360F - Families of Vascular Plants

Assignment 2 - georeferencing

Named places - UTM coordinates

After databasing the specimens for your species, you will undoubtedly find that some records lack geographic coordinates, or only have UTM grid references when what you need for SimpleMappr are latitudes and longitudes. This page will show you how to georeference as many of your specimens as possible. Please use the methods given here in descending order, since name searches seem likey to yield better results than will converting most of the UTM data available on the specimens.

Named places - Outside York Region named places may be findable using tools like The Atlas of Canada online topographic map search function, or the Natural Resources Canada "Querying Canadian Geographical Names" page.

The first of these two has the advantage that the location is plotted on a map. The user can then increase the scale from 1:42 million to something like 1:100,000 by clicking in the scale box below the map and entering the new scale factor (without commas). The maximum resolution available is 1:20,000. If you can locate the feature of interest on the map you can click on the "Get Info from Map" at the top, then click on the feature you've located, and a window will open containing coordinates for the point on which you clicked. The difficulty with this method is that sometimes the feature you are looking for is not immediately visible, or it is difficult to decide what part of the feature (e.g. a river) to choose, unless the specimen label provides additional information.

The second tool may appear easier to use just because the user does not need to find a location on the map. Instead, you are just given the geographic coordinates. You could plug these coordinates into the the Atlas of Canada search function and then check the resulting map at an appropriate scale, to see if they make sense.

In both cases, remember that your desire for a precise and accurate location should be tempered by remembering that you will be plotting your results on a scale of the province as a whole (1:10 million?) so that inaccuracies of up to 10 km will not be critical. Points that land in the middle of water bodies will, of course, look silly.

Toporama Search page

GNSS Name Search page

GNSS Name Search function (above).

GNSS Name Search results (at right). Note that you must select the most appropriate choice if more than one result appears in the upper window (this is true with the Atlas of Canada search function as well).

GNSS Name Search results

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UTM coordinates - Latitudes and longitudes can be obtained from UTM coordinates using a slightly modified version of the spreadsheet provided by Steven Dutch, Natural and Applied Sciences, University of Wisconsin - Green Bay, that is described HERE (this site also provides a good explanation of what UTM coordinates are).

The problem with converting the UTM coordinates found on many TRT specimens is that many of them appear to be very inaccurate, quite apart from the fact that many collectors failed to provide the UTM zone (actually, this problem is not insurmountable if you have a rough idea of the location). If only three digits (nnn) are supplied for the Easting and Northing, they can be filled out as follows: E nnn000, N nnn0000, and the filled-out coordinates inserted into the spreadsheet. To check the results you obtain with the spreadsheet you can enter the latitude and longitude into the The Atlas of Canada online topographic map search function, and see if the map location you get makes sense.

UTM converter, top page

One-at-a-time conversions (above).

UTM converter, batch page

Batch conversions (above).

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Please send your comments to tim.dickinson@utoronto.ca; last updated 25-Nov-2012