I'm sure they mean accuracy instead of precision. Precision is just
the number of digits stored/displayed, whereas accuracy is how well the data
reflects reality. Just because you chose to display coordinates to the
nanometer doesn't mean they are that accurate. Not that I want to confuse the
issue, but it can be important.
Most (some? all?) of the CanVec data originally came from the 1:50,000
NTS topographic maps . Within the past few decades some have been updated from
medium-resolution satellite imagery, and some have been updated with data from
the various Provincial 1:20,000 mapping initiatives. At any rate, the
"Quantitative Horizontal Accuracy Value" is given in the metadata for each NTS
sheet, with a number 30 meters being common.
To stir the pot even more, the Manitoba government
(https://mli2.gov.mb.ca//) has it's 1:20k topographic maps available for free
(and the license looks libre too). Their metadata gives accuracy values
(Horizontal_Positional_Accuracy) of 1.25 meters, 2.5 meters, etc. Wow! I
expected 20 meters at best.
And don't get me started on the accuracy of hand-held navigation-grade
GPS receivers...
Best Regards,
Brent Fraser
Richard Weait wrote:
> Hi folks,
>
>>From the good folks at Natural Resources Canada (GeoBase).
>
> "Yes you can use the data found on GeoGratis site . The licences are
> identical. The only differences are the copyrights, one is GeoBase,
> the other one is NRCan (GeoGratis).
>
> Please note: The data found on GeoGratis could have different
> planimetric precision and could not fit exactly with the precise GeoBASe
> data or OSM data. Please refer to the metada info of the files you will
> be using."
>
> I'm sure that we are all excited about the additional data. Please note
> the guidance regarding precision.
>
> Best regards,
> Richard
>
>
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>
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