[Qgis-user] Is location info included in metadata when save an image file?
Kirk Schmidt
kirk at nortekresources.com
Mon Jun 3 07:01:06 PDT 2019
Hi Ert:
You can save locational data in jpg and pdf files from within the Print
Composer window. Under composition tab on the right hand side of the
window, scroll down and check the Save World File checkbox. Export your
map/composition as a jpg or pdf and the geolocation data will be written
to a world file for a jpg and internally for a pdf.
Good luck
Kirk Schmidt
On 6/2/2019 4:26 AM, Ert Four wrote:
> Thank you Alex and Roxo for your replies.
>
> From what I can tell the SVG and JPG files probably don't have location info in them, but it's also hard to tell what exactly the data is in some places, especially in the SVG.
>
> It looks like qgsmaprenderertask.cpp was written two years ago, which was after 2.14 came out.
>
> I will post on the developer list per Alex's suggestion. All of this is trying to prove that something doesn't exist -- which is always hard.
>
> Thanks again.
>
>
>> On June 1, 2019 at 4:41 PM "Fernando M. Roxo da Motta" <petro at roxo.org> wrote:
>>
>>
>> On Thu, 30 May 2019 17:09:59 +0200 (CEST), Ert Four <4ert at mailbox.org>
>> wrote:
>>
>>
>>> Does any coordinate or location data get embedded in the image file
>>> if I use Project > Save as Image or Composer > Export as
>>> Image/PDF/SVG?
>>>
>>> I'm using QGIS version 2.14.3 Essen, although I would like to know
>>> about more recent versions, too, for when I upgrade later.
>>>
>>> (I'm aware of the option to check "World file on" and create a
>>> separate world file. What I need is to make sure there is no
>>> identifying info whatsoever from the project file in the image file
>>> itself.)
>>>
>>> Eg, say I have a basemap like OpenStreetMap open for a country and I
>>> load points in another layer that are inside that country. Then I
>>> zoom in on a group of points from my data layer, I turn off the
>>> basemap layer, and make a map with just my data points. I want to
>>> preserve the relative spatial relationships between my points but not
>>> reveal where in the world the map came from. If I publish this image
>>> file, might the metadata reveal the location?
>>>
>>> For the work we do, it's critically important we not unknowingly
>>> publish specific locations.
>>>
>> AFAIK, if you save in PNG or JPEG format no coordinate information is
>> stored in metadata of the image:
>>
>> $ exiftool Inhambu.jpg
>> ExifTool Version Number : 10.80
>> File Name : Inhambu.jpg
>> Directory : .
>> File Size : 49 kB
>> File Modification Date/Time : 2019:06:01 11:37:04-03:00
>> File Access Date/Time : 2019:06:01 11:37:04-03:00
>> File Inode Change Date/Time : 2019:06:01 11:37:24-03:00
>> File Permissions : rw-r--r--
>> File Type : JPEG
>> File Type Extension : jpg
>> MIME Type : image/jpeg
>> JFIF Version : 1.01
>> Resolution Unit : inches
>> X Resolution : 96
>> Y Resolution : 96
>> Image Width : 917
>> Image Height : 665
>> Encoding Process : Baseline DCT, Huffman coding
>> Bits Per Sample : 8
>> Color Components : 3
>> Y Cb Cr Sub Sampling : YCbCr4:2:0 (2 2)
>> Image Size : 917x665
>> Megapixels : 0.610
>>
>> $ exiftool Inhambu.png
>> ExifTool Version Number : 10.80
>> File Name : Inhambu.png
>> Directory : .
>> File Size : 47 kB
>> File Modification Date/Time : 2019:06:01 11:37:04-03:00
>> File Access Date/Time : 2019:06:01 11:37:04-03:00
>> File Inode Change Date/Time : 2019:06:01 11:37:44-03:00
>> File Permissions : rw-r--r--
>> File Type : PNG
>> File Type Extension : png
>> MIME Type : image/png
>> Image Width : 954
>> Image Height : 652
>> Bit Depth : 8
>> Color Type : RGB with Alpha
>> Compression : Deflate/Inflate
>> Filter : Adaptive
>> Interlace : Noninterlaced
>> Significant Bits : 8 8 8 8
>> Pixels Per Unit X : 3780
>> Pixels Per Unit Y : 3780
>> Pixel Units : meters
>> Image Size : 954x652
>> Megapixels : 0.622
>>
>> If you save as geotiff the positioning information should be written
>> in metadata. I don't know about the PDF format. In any case, all
>> informations, except the CRS, will be written to the world file.
>>
>> HTH
>>
>>
>>> Thank you, first time posting, very much appreciate QGIS and its
>>> community!
>>
>>
>>
>>
>>
>>
>>
>> Roxo
>>
>> --
>> ---------------- Non luctari, ludare -------------------+ WYSIWYG
>> Fernando M. Roxo da Motta <petro at roxo.org> | Editor?
>> Except where explicitly stated I speak on my own behalf.| VI !!
>> PU5RXO | I see text,
>> ------------ Quis custodiet ipsos custodes?-------------+ I get text!
>>
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--
Kirk Schmidt, MScF, BScF, RPF
General Manager
Nortek Resource Solutions Inc.
RR # 1
Thorburn, NS
B0K 1W0
Tel (902) 922.3607
Email: kirk at nortekresources.com
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