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Map Storage (in the IT sense)

Where to keep the files, backup, version control

MT: Michael Posted: 15 November 2008, 1:09 PM

Bryan wrote, “With some clubs creating a master OCAD file combining all their maps in one file…” Maybe I'm old-fashioned, but I'm wary of putting too much in one file. Eggs in one basket and all that.

I think the important thing is to have related maps on the same coordinate system, and with the boundary a tidy feature like a road, so that you can import one into another and have them match perfectly.

What file sizes are mappers getting up to?

MT: Michael Posted: 16 November 2008, 4:06 PM

OHV's largest maps are its super-topos which cover 1300 from Wellington to Waikanae. (The same mapping is used for rogaines and MTBO, planners give me updates event by event.)

When I started on these some years ago I wasn't at all sure what the limits were, and with previous computers I did have “freezing up” problems, usually when I was swapping between large template files (orthophotos). At any rate I divvied up the area into 7 files. I put these on the same paper coordinate origin so I could join adjacent ones together perfectly. (The import using real-world coordinates wasn't then possible). These are now 2-5mb each.

I no longer have any problems that might be size-related. However an example of the “feeling in my bones” is a problem I have with “partial map” on one of these files. When using a curved “selected object” as the cut line, the partial map sometimes contains stuff outside the line, and some stuff (usu contours) inside the line is missing. By subdividing into files at least this problem is minimised.

A more significant issue I would think is that of a club which has several mappers (or contractors). One needs to give update rights for a file to one person at a time. One wouldn't want to lock up half of Woodhill because someone is working in one corner of it.

MT: addison Posted: 16 November 2008, 6:19 PM

Hi Michael,

I think the key to the update rights issue is something that is based along the lines of an online storage for clubs. You download the latest version of the map for when you are doing fieldwork, then the moment you finish you reupload. This shows what file you used to do the updates - there is fields for descriptions of what you have changed etc… and the file online could even be 'locked down' until the file is reuploaded. Yes this would have issues, but the reality is if people download quickly, do their work, then upload - it would be a relatively smooth approach

MT: Michael Posted: 14 July 2014, 10:03 AM

Have any Dropbox users met this? Uploaded an OCAD file. Went to use the original again and “cannot open file…” Sidelined the offending file, downloaded, opens OK. Later, signed out of Dropbox; the offending file now opens successfully. Dropbox to blame or is it coincidental?

MT: mcroxford Posted: 14 July 2014, 8:41 PM

I has a problem with a mystery disappearing file about a month ago that reappeared again. Put an OCAD map in a folder and shared link on the course planning workshop I was running. Everyone accessed it before the training got there opened Dropbox and nothing was there. Got home and behold it was there again.

MT: Michael Posted: 14 July 2014, 11:57 PM

May indicate deeper problems with Dbox? Any other issues out there? Is it a suitable place to keep a club's master files?

MT: Michael Posted: 5 August 2014, 1:54 PM

Further to above Dropbox issue, it hit me today except in regards to largish background files. An OCAD file that wasn't sent via Dropbox refuses to open because its backgrounds WERE. Furthermore it freezes OCAD and I have to “end process” to get out. All pointing to my Dropbox sign-in as the problem because when I sign out it goes away.

mapping/mapstorage.txt · Last modified: 12:50pm Tue 25 October 2022 by