AW: AW: [udig-devel] Heap space error adding/removing graphical
layers
Jesse Eichar
jeichar at refractions.net
Thu Dec 7 06:05:03 PST 2006
Thanks Michael, I will look in to the problem and will get back to
you this evening on what I found.
Jesse
On 7-Dec-06, at 12:26 AM, Schneider, Michael wrote:
> Jesse, thanks for the answers.
> Sure, it's better to use one large shapefile instead of several
> smaller ones. I tried that after detecting the heap space problem
> with the gif files.
>
> I think it is not the maximal amount of memory which causes the
> problem, but perhaps a memory leak or memory fragmentation: Even
> when adding and removing only one single layer I detect that
> problem after having added and removed a layer more than 30 times.
>
> Michael
>
> Von: udig-devel-bounces at lists.refractions.net [mailto:udig-devel-
> bounces at lists.refractions.net] Im Auftrag von Jesse Eichar
> Gesendet: Mittwoch, 6. Dezember 2006 18:13
> An: User-friendly Desktop Internet GIS
> Betreff: Re: AW: [udig-devel] Heap space error adding/removing
> graphical layers
>
> Hi,
>
> There is a limitation to the number of layers that can be
> realistically added because currently each layer has a buffer that
> it writes to that is the size of the screen and is in 32-bit
> colour. Obviously a good chunk of memory especially when the
> screen is large. So it is better to have large shapefiles than
> many shapefiles because the Shapefile renderer is highly optimized
> for large shapefiles and performance will be much better rendering
> a 1 GB shapefile than 100 100KB shapefiles.
>
> This decision was part of the design because it allows some fun
> optimizations (for example enabling and disabling layers) but as of
> 1.1.1 we will have an "intelligent" system that will set a maximum
> number of buffers depending on the memory size so that this issue
> will no longer be a problem.
>
> Jesse
>
> On 6-Dec-06, at 3:54 AM, Schneider, Michael wrote:
>
>> Is grid coverage also involved when the layers are created from
>> shapefiles?
>> Using a bunch of shapefile layers instead of the GIF layers I also
>> ran into the same heap space error after adding and removing the
>> layers several times. (Each shapefile only had one single feature,
>> a point in this case.)
>>
>> Michael
>>
>> Von: udig-devel-bounces at lists.refractions.net [mailto:udig-devel-
>> bounces at lists.refractions.net] Im Auftrag von Jesse Eichar
>> Gesendet: Dienstag, 5. Dezember 2006 18:47
>> An: User-friendly Desktop Internet GIS
>> Betreff: Re: [udig-devel] Heap space error adding/removing
>> graphical layers
>>
>> Hi
>>
>> There are 2 main possibilities that I can think of.
>>
>> 1. Make sure that you are passing in a heap space parameter to
>> your application or increase it if you already are. For example
>> -Xmx512M will assign 512 MB of memory to the heap space of the
>> JVM. That should help with the problem.
>> 2. GridCoverage support is less than perfect at the moment
>> (although Jody is playing with a new version that shows promise)
>> and takes much more memory than it should. So it is likely that
>> the World+Image is what is causing problems. I'm not totally sure
>> what can be done about this. But if it is causing problems then
>> perhaps some memory optimizations can be made.
>>
>> Jesse
>>
>>
>> On 5-Dec-06, at 3:33 AM, Schneider, Michael wrote:
>>
>>> Hello,
>>>
>>> using uDIG RC 5 I got a heap space error after adding several
>>> layers. Each layer was created from a very small graphic (png or
>>> gif file of less than 1 KB) together with a world file. The same
>>> was true when each layer was created from a small shapefile.
>>>
>>> The intension is as follows: The user creates a list of locations
>>> and these locations are shown on a map. When creating a new list
>>> of locations, the old locations are removed from the map and the
>>> new ones are displayed.
>>>
>>> I did it similar to the descriptions in the FAQ "How do I create
>>> a map programmatically" and "I want to add an image to the map,
>>> how do I do that?"
>>>
>>> I created a map using createCreateMapCommand
>>> I added about ten layers (see above what the layers looked like)
>>> with either createAddManyLayersCommand (all layers together) or
>>> createAddLayerCommand (one layer at a time)
>>> When a new list was created I removed the old layers using
>>> createDeleteLayer command, set the new bounding box with
>>> createSetViewportBBoxCommand and added the new layers to the map.
>>> After doing these several times I run into the heap space error.
>>> I also get this error when I only add and remove one layer (i.e.
>>> location lists with only one entry), but it takes longer to get
>>> the error.
>>>
>>> I also tried it "the old way" with MapFactory.processURLs - with
>>> a similar result: The error appeared as well, but it took longer
>>> to get it.
>>>
>>> Am I doing it the wrong way? Is there a better way?
>>>
>>> I also wanted to try RC 6a. Are there any changes related to the
>>> layers view and showing the map? In RC 5 after adding the layer
>>> to the map they were displayed at once. In RC 6a I can see them
>>> in the catalog and in the project window, but they do not appear
>>> in the layers view automatically and are not displayed. I'll have
>>> a closer look to that to see whether I get the heap space error
>>> in RC 6a as well.
>>>
>>> Michael
>>>
>>> _______________________________________________
>>> User-friendly Desktop Internet GIS (uDig)
>>> http://udig.refractions.net
>>> http://lists.refractions.net/mailman/listinfo/udig-devel
>>
>> _______________________________________________
>> User-friendly Desktop Internet GIS (uDig)
>> http://udig.refractions.net
>> http://lists.refractions.net/mailman/listinfo/udig-devel
>
> _______________________________________________
> User-friendly Desktop Internet GIS (uDig)
> http://udig.refractions.net
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