1200 *.tif - very slow rendering certain images

stkorn

Hello, Dear customer service,

I would like to ask couple of questions about global mapper.

We have a workspace containing 1200 *.tif images. They are both color and black-and-white images with different opacity and contrast adjustment settings.

Some of the images (large black-and-white *.tif images) on a scale range 1: 20 000 – 1: 2000 renders very slow; while on a scale 1:50 000 or 1:1000 the same images renders 5 times faster. (3 seconds in comparison to 15 seconds)

There’s no such bug when I create a new project containing only one of that images. But the bug occurs when I create a whole project containing 1200 images.

The speed of rendering slows down only for a certain type of images and only for a certain range of scales. I have tried to change opacity and contrast adjustment settings, and it haven’t helped.

If I hide all the images but one, its rendering speed doesn’t change (remains slow). Saving the project and opening it again doesn’t help.

If I close all the images but one, it still renders slow. The speed becomes normal after I close the project and open it again.

Probably the bug occurs because of the huge amount of images in the project, even if they are hidden.

The same happens during export, when export grid comes up to a tile with that “slow image”. It takes 2 hours instead of 2 minutes to generate a 5 x 5 km area image with 0.35 resolution.

I am using 11.02 version (64-bit). Windows 2008 Server, 8Gb RAM. Versions 11.01 32-bit and 64-bit work with the same speed. In version 9 there was no such bug.

Updating from the archive http://www.globalmapper.com/global_mapper11_64bit.zip didn’t help.

The are no vector shapes in the project. During the bug there’s 100% usage of one of the CPU cores. Process global_mapper.exe allocates 200Mb of the memory.

I have found the same topic on the forum, but there’s no solution
http://www.globalmapperforum.com/forums/raster-data/4262-export-geotiff-slowing-down.html#post9648

Thank you very much,
I appreciate your help.

global_mapper

The issue is definitely the number of TIFF files that you have open at once. The first few loaded files will be loaded with the fastest possible access, but as the number of files open increases slower access has to be used for the later ones.

Luckily there is a solution! If you use the File->Create New Map Catalog menu command to create a map catalog from the TIFF files rather than loading them directly, then your files will be loaded and unloaded as needed for display and export, significantly speeding up display for such a large number of files.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

stkorn

I have tried to create map catalog, but when I zoom on some scale range- the rendering becomes still very slow.

Example: I have one active .tif image (~500 Mb) and ~600 different hidden .tif layers.
When I zoom on 1:30000 rendering time of the screen is 5 sec.
When I zoom on 1:15000 rendering time of the screen is 30 sec.
When I zoom on 1:5000 rendering time of the screen is 30 sec.
When I zoom on 1:1500 rendering time of the screen is 2 sec. (!)

When I close all other images but one, save and close the project, and open it again - the speed is fine (2-5 sec) on all scales.

global_mapper

It's still possible that for a view you still have enough TIFF files open that some are using the slow access, particularly if you have a very large TIFF open. I did notice that the 64-bit builds of GM were switching to slower access at the same memory usage as 32-bit builds, which was not necessary. I have updated the 64-bit build to allow loading a lot more data before switching to slow access. I have placed a new build at http://www.globalmapper.com/global_mapper11_64bit.zip with the change for you to try. Simply download that file and extract the contents into your existing v11.xx installation folder to give it a try.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

stkorn

Thanks for the help!

Just one more question:

I create the map catalog, and add .tif files with linear contrast adjustment.
I select the style of bounding boxes for this map catalog.
I zoom in this region, and whait for auto-contrast statistic calculating.
I save my workspace and close it.

When I open this workspace next time, and zoom in, I should wait again for auto-contrast statistic calculation. And my bounding boxes styles of map cataloges are forbidden and replaced by default styles.

How I can save auto-contrast statistic and bounding boxes styles of map catalog?

global_mapper

I have updated map catalogs to now save the calculated contrast statistics so that they don't have to be continuously recalculated for each layer. I also fixed the issue with some custom bounding box styles not saving properly. I have placed a new build at http://www.globalmapper.com/global_mapper11.zip with the change for you to try. Simply download that file and extract the contents into your existing v11.xx installation folder to give it a try. If you are using the 64-bit version, there is a new build available at http://www.globalmapper.com/global_mapper11_64bit.zip .

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

stkorn

Thanks for your prompt response!

Map catalog is the best solution for mosaics of thousand rasters.
Now all works quickly on all scales!

Customising of bounding boxes styles and percent of display size - is realy great solution to arrange and work with many rasters!

Now full view redndering time is 5 seconds in comparison to 15 minutes, when all rasters have been included in the workspace directly.

Here is the screenshoat of my Global Mapper: 1198 .tif files total amount of 314 Gb.