Hi Michael,

If you have downloaded the original pdf file, then it is important to catalog the page size and the scale of a map. This will allow a patron to print the map in actual size. If the digital map has a graphical scale (the map you downloaded does have both RF and graphical scale), then you don't need to worry about whether the patron will zoom in or out to look at the map and measure distances. The graphical scale will change according to the zoom level. Because of this, most cartographers will use both the RF and the graphical scale on a map. If the map has a graphical scale (scale bar) then it does not matter if the map has been enlarged or reduced; the scale will still be correct. 

The actual size of the Okavango River Basin map you downloaded is 28.94 x 30.10 inches. 

Hope this information is helpful to you.

Thanks,

-Wangyal

Tsering Wangyal Shawa

GIS and Map Librarian

Head, Map and Geospatial Information Center

Peter B. Lewis Library

Washington Road & Ivy Lane

Princeton University, Princeton, NJ 08544

Telephone: 609-258-6804

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Make an appointment

http://library.princeton.edu/collections/pumagic

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From: Maps-L: Map Librarians, etc. <[log in to unmask]> on behalf of Fry, Michael <[log in to unmask]>
Sent: Tuesday, October 26, 2021 4:10 PM
To: [log in to unmask] <[log in to unmask]>
Subject: cataloging and map scale variability

 

Hi,

The ubiquity of the Internet means that maps (or map image files) are increasingly available for download from all kinds of map publishers (e.g., UN and many national mapping orgs that no longer sell paper maps). Which is great. But it almost certainly means that users will increasingly view maps at a scale different from what's actually printed on those maps. 

Here's a specific example. Several years ago, I downloaded, printed (at poster size), cataloged, and shelved in the collection this 1:2M UN map of the Okavango River Basin. Now that we have a facility for storing map imagery, etc., I can link the digital object to the same catalog record and give users the option to see the map in both print and digital format. But in neither case--our print copy or the PDF--is the scale stated on the map likely to be the same scale that users see the map at. Unless, of course, I just happened to print it to the exact dimensions the UN had in mind when they set the map to 1:2M (unlikely) or users view the PDF version only at the zoom level consistent with 1:2M (also unlikely). 

Is there anything to be done about this other than continuing to record the scale as it appears on the map? If the map was printed from a digital file--or if you know the map to be a reproduction or facsimile of some kind, could one note this somewhere and point out that the true scale of the map may differ from the stated/recorded scale?

Thank you.

mf

--

Michael Fry
Collections Manager | Map Library Manager
National Geographic Society Library
202.807.3139

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1145 17th St., NW, Washington, DC 20036