OziExplorer problem

Submitted: Saturday, Jun 17, 2006 at 20:34
ThreadID: 35023 Views:4327 Replies:6 FollowUps:10
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I have the current Natmap 250k map DVD (this does not have the individual 250k maps .. just the mosaics). In addition to loading some map mosaics of WA (for a forthcoming trip) I also want to load the individual 250k map of Melbourne (SJ5505). This is because my SD card is only 2GB .. ie: can't load 3 mosaics.

So I downloaded the SJ5505 map image from the Geoscience Aust website & the mapfile from OziExplorer. When I open the mapfile in OziExplorer it launches the corressponding map image but it doesn't seem to find my location properly (you can see part of the map image to the side of the screen but most of the screen is just blank. Are the maps on the Natmap Raster CD different to the ones you would download from the Geoscience Aust website? What else could be the problem?

If I do need the specific map from the CD could someone email me a copy please (thorntonz@optusnet.com.au)
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Reply By: Old Scalyback & denny - Saturday, Jun 17, 2006 at 21:42

Saturday, Jun 17, 2006 at 21:42
which side of melb are you i am in between cranbourne and dandenong
i have some maps you could try

steve
AnswerID: 178997

Follow Up By: Member - Drew T (Melbourne) - Sunday, Jun 18, 2006 at 14:53

Sunday, Jun 18, 2006 at 14:53
thanks Steve, but Andrews suggestion (below) to create a new mapfile for the downloaded map worked just fine
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Reply By: Gu_Patrol - Sunday, Jun 18, 2006 at 08:09

Sunday, Jun 18, 2006 at 08:09
I think you have to convert the maps to Ozf3 to use them on your PDA, I take thats why your using a 2meg card, correct me if I'm wrong.
AnswerID: 179029

Follow Up By: Peter 2 - Sunday, Jun 18, 2006 at 08:22

Sunday, Jun 18, 2006 at 08:22
I've found the easiest way since using the PDA instead of the laptop is to open the map in Ozi on the PC, make sure it is working ok (map files etc are correct).
Then convert it to ozf3 and save it into a seperate file for each trip. This way you can download the required maps for each trip onto the mem card when required.
Then download it into the card in the pda using a direct cable rather than the docking station as the dock 'freezes' occasionally during large file transfers.
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Follow Up By: Member - Drew T (Melbourne) - Sunday, Jun 18, 2006 at 12:19

Sunday, Jun 18, 2006 at 12:19
the version i'm using can (& does) use the ecw files so no need to convert
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Reply By: agsmky - Sunday, Jun 18, 2006 at 09:12

Sunday, Jun 18, 2006 at 09:12
The GA downloads (in ECW format) are different from the purchased versions (Natmap Raster 2005 standard etc) in that they have no borders (marginal iinformation etc) in the image. Last time i looked, Oziexplorer website didn't have the .map files for this set. No need for them anyway, as it only takes seconds to make.

As they are ECW files, just import them into Ozi (via file==>import map==>single DRG map, this selection will import only that map) and Ozi will create the corresponding .map file. I just tried SJ5505 and it worked perfectly.

BTW there is no need normally to convert these maps to OZF2/3 format as OziExplorerCE can use ECW files (with their associated .map file). You may achieve a decrease in file size, at the expense of some reduction in quality. IMO, if you have the room for a 3.8mb file, just load it onto your SD card with little hassle.

Andrew
AnswerID: 179033

Follow Up By: The Explorer - Sunday, Jun 18, 2006 at 11:50

Sunday, Jun 18, 2006 at 11:50
Hello - I have found ecw files to be a bit slow loading/updating on the PDA (though it does depend on file size). I would recommend converting to OZF whenever you can. The resulting OZF file may or may not be larger in size than the ECW - depends on the compression ratio used to create the ECW file. From my expereince you will not normally see (because there is none?) any loss in image quality when converting your average map to OZF - unless you dramatically change number of colors to get a smaller file.
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Greg
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Follow Up By: agsmky - Sunday, Jun 18, 2006 at 12:29

Sunday, Jun 18, 2006 at 12:29
Thanks Greg.....Just tested the conversion of this ECW file to Ozf2 or Ozf3 format , would be about 8.12mb and 7.51mb respectively using 256 colours. Would be interested to see the balance between these larger file sizes and the speed of loading/displaying with this map (i'm aware of how the formats load WRT oziCE etc)

Andrew
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Follow Up By: The Explorer - Sunday, Jun 18, 2006 at 12:58

Sunday, Jun 18, 2006 at 12:58
Andrew - I was speaking in general terms and based on my use of some pretty big ecw files (airphotos), maybe not applicable in this case - I rarely use the 250K maps on my PDA (in any format - not enough detail) and so can not state specifically in this case whether ECW is better or worse than OZF (with respect to loading and panning). I have a lot of 25 and 50k maps as OZF3. They are converted from about 80mb tiffs to about 10mb OZF3. I have also converted some to ECW (compression set at 10) - file size is smaller ..say 60% of OZF. The OZF load on my PDA (ipaq 2790) in less than a second...the ECWs slightly slower ..maybe 1 second. When panning the OZF appear to load a fraction faster also. So it appears for smaller files (up to say 20mb) there is didley squat difference between OZF and ECW - there is a difference but it is not what I would call significiant or likely to cause frustration in the bush (not good)...so as you suggest ecw in this case (250K maps) would be the go if you're tight on memory. But over all I like OZF3 better..SD cards are pretty cheap.
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Greg
I sent one final shout after him to stick to the track, to which he replied “All right,” That was the last ever seen of Gibson - E Giles 23 April 1874

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Follow Up By: Member - Drew T (Melbourne) - Sunday, Jun 18, 2006 at 14:51

Sunday, Jun 18, 2006 at 14:51
thanks Andrew .. your answer was spot on & the mapfile created by OziExplorer works perfectly
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Follow Up By: agsmky - Sunday, Jun 18, 2006 at 20:01

Sunday, Jun 18, 2006 at 20:01
That's ok, Greg......It's good to know that info. Personally i like to keep my maps as high resolution as possible. I normally use aerial photographs in TIF format (LZW compression), around 17-270mb :-) I have found that when using aerials, it pays to keep the colours in the resulting image, and therefore any conversion to 256 colours or less (eg ozf2/3 etc) results in less than ideal images (especially when containing water etc) for my purposes. Thanks for the better understanding of the differences when used on a PDA.

I suspect that the conversion/compression used by GA to make the ECW files are of such a nature that they are the best balance of compression and colour factors.

Drew T, i'm glad that the information helped.....

Andrew
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Follow Up By: The Explorer - Sunday, Jun 25, 2006 at 18:23

Sunday, Jun 25, 2006 at 18:23
Just for the record - not all PDA's that can use OziCe can open ECW files - something to do with processors - only units with ARM processors can utilise ECW images...others are restricted to OZF format.

Cheers
Greg
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Reply By: Alan H (Narangba QLD) - Sunday, Jun 18, 2006 at 10:08

Sunday, Jun 18, 2006 at 10:08
With a PDA I use the zone maps from the Natmap DVD. Melbourne would be about zone 54 without checking. I find these work fine and are about 800MB per map so I have a couple of SD cards and swap them if travelling long distances east west. Most trips are contained in one map as most trips from Bris are north south.

I don't convert these maps but just use the ECW file and they work fine.

I am about to go to the gulf country and Brisbane to Lawnhill will cause me to swap SD cards as the trip is across three zones. Just a couple of seconds to swap cards and then load new map.

I would have thought individual sheet maps (1:250000) would require many maps for a trip of reasonable size. I would however use individual maps for larger scale maps to get more detail if required and if available.
AnswerID: 179039

Reply By: Member - Leigh (Vic) - Sunday, Jun 18, 2006 at 19:16

Sunday, Jun 18, 2006 at 19:16
I am at about hour 28 converting the Natmap mosaic to OZF3. Seems to be taking forever but the end is in sight. Thankfully my other maps are already in ozf2 and work well on the pda. Great learnig experience though!!
AnswerID: 179100

Follow Up By: signman - Monday, Jun 19, 2006 at 09:10

Monday, Jun 19, 2006 at 09:10
Leigh
No need to convert ecw to ozf3 to use on PDA...
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Reply By: Member - Oldplodder (QLD) - Sunday, Jun 18, 2006 at 20:06

Sunday, Jun 18, 2006 at 20:06
On my copy of the natmap DVD is a viewing utility.
It will also create a geotiff file of the current view.
So load the ecw file you need and create the required tiff file.
Then use the ozf3 converter for a file to use on the pda.

Found the process listed on the oziexplorer help pages.
AnswerID: 179105

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