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mmchenry15 post(s)
#19-Jun-15 20:01

Hello,

I have 36 ecw files (3760kb each) that i am linking to my map. Normally files this size load very quickly. However, they are taking quite some time to add to the map initially and are still slow once linked. Any suggestions as to why this may be happening? (ecw's were converted through a batch export from jp2).

Thanks

cartomatic

905 post(s)
#20-Jun-15 10:09

mosaick them and use one ecw. quite often this improves things a lot as you read from one source instead of xx


maps made easy - www.cartomatic.pl || www.cartoninjas.net

mmchenry15 post(s)
#22-Jun-15 13:33

I am now running into the issue where opening just one of the linked ECW's causes a (Not Responding) prompt in Manifold. Could my original jp2 files be corrupt? Or something happened in the process of assigning the proper projection and batch exporting as ecws?

update - linking the original jp2's in the original projection seems to be much quicker, is it better to work with ecw's over jp2's? I have 36 images. HOWEVER, zooming in is still relatively slow.

- if so, should i also mosaic all the jp2's as well?

cartomatic

905 post(s)
#22-Jun-15 14:23

in general ecw should be lightning fast, so:

* are you linking or importing?

* can it be related to some network connectivity problems - usb drive, network drive, etc?


maps made easy - www.cartomatic.pl || www.cartoninjas.net

mmchenry15 post(s)
#22-Jun-15 15:05

I am linking. Yea i have worked with much larger image files before and once exported as ecw and linked there is no issue with loading time. I am also working off of the desktop to ensure no issues with connectivity.

I am investigating now, i think perhaps projection may be the issue. I have just converted all jp2's to lambert azimuthal equal area and will export as ecw. I will also assign the same projection to all drawings with the project. (my project is in both zone 16 and 17 NAD83, however all files have an assigned projection of zone 17).

cartomatic

905 post(s)
#22-Jun-15 17:25

manifold will not reproject ecw on the fly so indeed a large number of vector objects being reprojected may be the issue here. still manifold has that partial rendering thing so you should see the raster rather quickly. as long as it's not painted last.


maps made easy - www.cartomatic.pl || www.cartoninjas.net

mmchenry15 post(s)
#22-Jun-15 18:08

I'm at a loss now. I opened a bran new project (with no vector drawings within it) and linked 10 ecw's (in their original projection) and imported into the same map and the program continues to load slowly and not respond...

When i link larger ECW's from older projects i have no problem.

Ive attached one of the original jp2 files - all are the same size.

Attachments:
1km175570479602010MAPCON.jp2

rkleinecke8 post(s)
#22-Jun-15 21:03

I work with over 4000+ tiles of these JP2's from MAPCON in Southern Ontario, which it looks like yours are located. I was not able to work with these tiles as they are incredibly slow. My solution was to first convert the tiles to TIF's and then convert to ECW's. I then mosaicked them into manageable blocks of 20 sq/km tiles. These mosaicked ECW's work great. So first export to TIF and then to ECW.

cartomatic

905 post(s)
#23-Jun-15 11:15

It looks to me that when you import or link that jp2 (and potentially any other) and then export it as ecw it simply copies the file, and maybe changes some headers, whatever. The result is that you end up with pretty much the same file that is slow due to its compression settings.

if you link / import the file and change it (image -> convert to) to rgb / argband then export as ecw, the resulting file behaves as expected - can be read quickly.

I do not see a ConverTo like method on the image object so i guess you should use ui scripting to invoke the ui menu commands, or alternatively you may use the RenderTo / RenderAreaTo methods to render the input jp2 to an image component of the same pixel size and then export the produced image.


maps made easy - www.cartomatic.pl || www.cartoninjas.net

mmchenry15 post(s)
#24-Jun-15 15:41

Thanks, the conversion from jp2 -->rgb and then export as ECW seemed to do the trick.

For future reference, do you know of any batch image converters to transform from jp2 to rgb?

cartomatic

905 post(s)
#24-Jun-15 16:40

you can script it in manifold. if you have global mapper here is an example of a batch converter: http://cartoninjas.net/post/globalmapper-batch-reproject-and-export-geotif-to-ecw


maps made easy - www.cartomatic.pl || www.cartoninjas.net

Gustavo Palminha

1,010 post(s)
#09-Jul-15 11:36

You can also use gdal to do it. No need to buy 3rd party apps.

So just export your data from manifold, script and run through gdal and link/import the result into manifold.


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