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Merge multiple RasterDataset

oyleiste

Hello

I can get Linear Line of Sight from a single DTED file; which had beed opened by:

IWorkspaceFactory wsf = new RasterWorkspaceFactoryClass(); IRasterWorkspace rasterWS = (IRasterWorkspace)wsf.OpenFromFile(foldername, 0); IRasterDataset rasterDS = rasterWS.OpenRasterDataset("n42.dt0"); //DTED Level 0 file

Single DTED file means that both observer and target are in the DTED file's area.

Well, the problem occurs when I load more than one DTED files and want to use these functions:

IRaster raster = rasterDS.CreateDefaultRaster(); RasterSurfaceClass rsc = new RasterSurfaceClass(); rsc.PutRaster(raster); [INDENT]rsc.GetElevation(point);[/INDENT] [INDENT]rsc.GetLineOfSight(blah, blah, blah);

[/INDENT]

If observer is in a DTED file and target is in another DTED file, GetLineOfSight function fails obviously.
How can I merge two RasterDataset to give rsc.PutRaster() function one single raster?
Or
How can I put more than one raster in RasterSurfaceClass?

Thank you
Sincerely

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Accepted answers

oyleiste

Well, after a lot of struggling with this stuff, I solved the problem :cool: I'll share the code and explain it, so people can use it easily.

If you want to merge/mosaic some IRasterDataset, you can use my code:

IRasterCollection rc = (IRasterCollection) new MosaicRasterClass();

#region Add some IRasterDataset to the rc (IRasterCollection)
rc.Insert(0, rasterDataset0);
rc.Insert(1, rasterDataset1);
rc.Insert(2, rasterDataset2);
rc.Insert(3, rasterDataset3);
#endregion

ISaveAs2 save = (ISaveAs2) rc;
IRasterStorageDef st = new RasterStorageDefClass();
IRasterStorageDef3 store = (IRasterStorageDef3)st;
store.CompressionType = esriRasterCompressionType.esriRasterCompressionUncompressed;
store.Tiled = false;
IRasterDataset resultDataset = save.SaveAsRasterDataset("ResultDTED.dt0", _workspace_, "DEM", store);

First, you should create a IRasterCollection and add some IRasterDataset into it. Then you should create ISaveAs2 and cast rc to it. Then create IRasterStorageDef stuff. Finally, use ISaveAs2's SaveAsRasterDataset function to save merged/mosaicked RasterDataset to file and use it's return value as IRasterDataset. resultDataset contains the merged dataset.

Thank everyone for replying, specially Jason.
Sincerely

All comments

oyleiste

IRasterCollection rc = (IRasterCollection) new MosaicRasterClass();

#region Add some IRasterDataset to the rc (IRasterCollection)
rc.Insert(0, rasterDataset0);
rc.Insert(1, rasterDataset1);
rc.Insert(2, rasterDataset2);
rc.Insert(3, rasterDataset3);
#endregion

ISaveAs2 save = (ISaveAs2) rc;
IRasterStorageDef st = new RasterStorageDefClass();
IRasterStorageDef3 store = (IRasterStorageDef3)st;
store.CompressionType = esriRasterCompressionType.esriRasterCompressionUncompressed;
store.Tiled = false;
IRasterDataset resultDataset = save.SaveAsRasterDataset("ResultDTED.dt0", _workspace_, "DEM", store);

oyleiste

I found out an interesting fact:
SaveAsRasterDataset returns IRasterDataset. As input, I gave SaveAsRasterDataset 2 DTED Level 0 in IRasterCollection.
So, I decided to store SaveAsRasterDataset's return data and explore it's contents. Returned IRasterDataset was DTED Level 1 !!

oyleiste

I tried this code for save mosaicked DTEDs:

IRasterCollection rc = new MosaicRasterClass();
rc.Insert(0, rasterDS[0].CreateDeafultRaster());
rc.Insert(1, rasterDS[1].CreateDeafultRaster());
ISaveAs2 save = (ISaveAs2)rc;
IRasterStorageDef st = new RasterStorageDefClass();
save.SaveAsRasterDataset("MosaicResult", (IWorkspace)_rasterworkspace_, "DTED", st);

The result file is 2.76 MByte and it's full of 0 elevation (full blue); and it's size is one of DTED's size, not twice (if mosaic was successful, result's size would be twice as one of DTEDs).

Any idea will be appreciated
Thanks

oyleiste

Unfortunately Mosaic function fails for DTED Level 2 too.
I created 2 DTED Level 2 files, with made-up data, loaded successfully in Arcmap but Mosaic function failed again.

Could you save it to a different format and use it?

What format? I tried some formats and all failed.
Maybe I should change my strategy!

By the way, I found this link that says DTED 0, 1 and 2 are supported (for ver. 10.1)

JasonPike

I just found this link that displays Raster formats for saving. There is no DTED in it.

I tried to copy my all DTED RasterDatasets to IRasterCollection using Append function, and save it using ISaveAs2.SaveAsRasterDataset, and then, load it from file again, but I couldn't save datasets as DTED. Code for this:
IRasterCollection rc = (IRasterCollection) new MosaicRasterClass();
rc.Append(rasterDS[0]);
rc.Append(rasterDS[1]);
ISaveAs save = (ISaveAs) rc;
IRasterStorageDef store = new RasterStorageDefClass();
store.CompressionType = esriRasterCompressionType.esriRasterCompressionUncompressed; //no idea!
save.SaveAsRasterDataset("ResultDTED", _workspace_, "X?", store);
You mean, if my DTEDs was level 1 or 2, Mosaic function wouldn't fail?

Thank you

Well, I'm speculating that a DTED level 1 or 2 would work--I can't find anything definitive. In the PDF I linked in my last post, it indicated that DTEDs were read-only, so that is probably why you can't save. Could you save it to a different format and use it?

oyleiste

I just found this link that displays Raster formats for saving. There is no DTED in it.

I tried to copy my all DTED RasterDatasets to IRasterCollection using Append function, and save it using ISaveAs2.SaveAsRasterDataset, and then, load it from file again, but I couldn't save datasets as DTED. Code for this:

IRasterCollection rc = (IRasterCollection) new MosaicRasterClass();
rc.Append(rasterDS[0]);
rc.Append(rasterDS[1]);
ISaveAs save = (ISaveAs) rc;
IRasterStorageDef store = new RasterStorageDefClass();
store.CompressionType = esriRasterCompressionType.esriRasterCompressionUncompressed; //no idea!
save.SaveAsRasterDataset("ResultDTED", _workspace_, "X?", store);

You mean, if my DTEDs was level 1 or 2, Mosaic function wouldn't fail?

Thank you

JasonPike

I would be surprised if DTEDs (any level) weren't supported--they are very common raster types. I'll keep digging as I have time. Please keep the forum up-to-date on your progress.

Well, I guess I'm wrong:
http://downloads.esri.com/support/ProjectCenter/Raster_Data_Management_-_Introduction_to_ArcGIS_Raster.pdf

Here is a presentation from 2004. I don't know if it is still relevant, but DTED 1 & 2 and supported, but DTED 0 isn't included in the list. I still haven't found a list of supported types in the 10.1 documentation.

JasonPike

Yes,   CreateDefaultRaster returns   IRaster; not   IRasterDataset. But keep in mind that   IRasterDatasetEdit.Mosaic gets   IRaster as first parameter, not   IRasterDataset. That's why I use   rasterDS[0].CreateDefaultRaster() function; to get   IRaster and pass it to   Mosaic function.

The link; creates a   IRasterDataset for a image (map). Because it copies   pixels into it. My   IRastarDataset's format is   "DTED Level 0", not map nor image. So, I think I can't use it.

I need more tea 😄

I get   IRasterDataset like this:
IWorkspaceFactory wsf = new RasterWorkspaceFactoryClass();
IRasterWorkspace rasterWS = (IRasterWorkspace)wsf.OpenFromFile(foldername, 0);
List<IRasterDataset> rasterDS = new List<IRasterDataset>();
rasterDS.Add(rasterWS.OpenRasterDataset(DTED_filename)); //"n34.dt0" for ex.
Yes, the documentation just says it's datatype: double ">😐

I would be surprised if DTEDs (any level) weren't supported--they are very common raster types. I'll keep digging as I have time. Please keep the forum up-to-date on your progress.

oyleiste

Yes, CreateDefaultRaster returns IRaster; not IRasterDataset. But keep in mind that IRasterDatasetEdit.Mosaic gets IRaster as first parameter, not IRasterDataset. That's why I use rasterDS[0].CreateDefaultRaster() function; to get IRaster and pass it to Mosaic function.

The link; creates a IRasterDataset for a image (map). Because it copies pixels into it. My IRastarDataset's format is "DTED Level 0", not map nor image. So, I think I can't use it.

I need more tea 😄

I get IRasterDataset like this:

IWorkspaceFactory wsf = new RasterWorkspaceFactoryClass();
IRasterWorkspace rasterWS = (IRasterWorkspace)wsf.OpenFromFile(foldername, 0);
List<IRasterDataset> rasterDS = new List<IRasterDataset>();
rasterDS.Add(rasterWS.OpenRasterDataset(DTED_filename)); //"n34.dt0" for ex.

Yes, the documentation just says it's datatype: double ">😐

JasonPike

Ah! CreateDefaultRaster() returns a raster, not a raster dataset!

You need a raster dataset to create the mosaic:
http://edndoc.esri.com/arcobjects/9.2/NET/dd494eb7-b56b-4e7a-adeb-0eccc1f9765c.htm

Once you create the raster dataset, you can cast it to IRasterDatasetEdit and use the mosaic function to add your rasters (created using the CreateDefaultRaster() method.

Make sense?

I now realize that is what you've been trying to do--I need more coffee.

How are you creating the raster datasets in your array?

The documentation is a little light on details. I'd like to know what the tolerance does--simply knowing that "tolerance is a parameter of type double" tells us nothing. Bah!

This tells you a little bit about the raster datasets. I would do some research into the terminology. I would ask questions about whether the cell sizes have to the same between rasters your merging, etc.
http://edndoc.esri.com/arcobjects/9.2/NET/dd494eb7-b56b-4e7a-adeb-0eccc1f9765c.htm

JasonPike

Actually, the first CreateDefaultRaster was mistake (I put it there for my own debugging).
Now, my code is like this:
[ATTACH=CONFIG]23082[/ATTACH]
But, still the same problem. Fails at Mosaic function. I have no idea about it's second paramter. I just give random numbers ">😐
Why there isn't any explanation or sample about this function?!
ArcGIS bored me a lot 😞

Thank you for your reply; Jason
Sincerely

Ah! CreateDefaultRaster() returns a raster, not a raster dataset!

You need a raster dataset to create the mosaic:
http://edndoc.esri.com/arcobjects/9.2/NET/dd494eb7-b56b-4e7a-adeb-0eccc1f9765c.htm

Once you create the raster dataset, you can cast it to IRasterDatasetEdit and use the mosaic function to add your rasters (created using the CreateDefaultRaster() method.

Make sense?

oyleiste

Actually, the first CreateDefaultRaster was mistake (I put it there for my own debugging).
Now, my code is like this:
[ATTACH=CONFIG]23082[/ATTACH]
But, still the same problem. Fails at Mosaic function. I have no idea about it's second paramter. I just give random numbers ">😐
Why there isn't any explanation or sample about this function?!
ArcGIS bored me a lot 😞

Thank you for your reply; Jason
Sincerely

Untitled2.png

JasonPike

After a lot of googling, I found out that I should create a IRasterDatasetEdit3, copy first DTED's IRasterDataset to it and then, append other DTEDs using IRasterDatasetEdit3.Mosaic function. Here is my code's screenshot:
[ATTACH=CONFIG]23074[/ATTACH]

Unfortunately Mosaic(IRaster raster, double tolerance) function fails at run-time execution. I have no idea why. Does anyone has idea?
By the way, that's tolerance (second parameter) in Mosaic?!
Please guide me to this 😞

Thank you
Sincerely

I don't know if there is any code above what you pasted in the screenshot, but from what I can see it appears that you didn't create the default raster for the first raster in the array. Maybe you can try the following:

IRasterDatasetEdit3 rasterDSE = (IRasterDatasetEdit3)rasterDS[0].CreateDefaultRaster();
for(int i = 1; i < rasterDS.Count; i++ )
{
 rasterDS.CreateDefaultRaster();
 rasterDSE.Mosaic((IRaster)rasterDS.CreateDefaultRaster(), 1000);
}

Also, I noticed that you're creating the default raster twice in the loop. While I doubt this is causing an exception, it is probably expensive and consuming a good bit of memory. Looking at the API, it doesn't seem like you would need the cast to IRaster either, but I haven't tried it.

rasterDS.CreateDefaultRaster();
rasterDSE.Mosaic((IRaster)rasterDS.CreateDefaultRaster(), 1000);

Try one of the following solutions:

#1 - Reuse output of first call

IRaster r = rasterDS.CreateDefaultRaster();
rasterDSE.Mosaic(r, 1000);

#2 - Don't make first call

rasterDSE.Mosaic(rasterDS.CreateDefaultRaster(), 1000);

I prefer #1 because it allows the opportunity to release the raster once you've added it to the mosaic:

IRaster r = null;

try
{
    r = rasterDS.CreateDefaultRaster();
    rasterDSE.Mosaic(r, 1000);
}
finally
{
    if( r != null )
     Marshal.ReleaseComObject( r );
}

JasonPike

After a lot of googling, I found out that I should create a IRasterDatasetEdit3, copy first DTED's IRasterDataset to it and then, append other DTEDs using IRasterDatasetEdit3.Mosaic function. Here is my code's screenshot:
[ATTACH=CONFIG]23074[/ATTACH]

Unfortunately Mosaic(IRaster raster, double tolerance) function fails at run-time execution. I have no idea why. Does anyone has idea?
By the way, that's tolerance (second parameter) in Mosaic?!
Please guide me to this 😞

Thank you
Sincerely

You did a great job annotating the screen capture! Can you put a try-catch block around the code that fails and dump the contents of the exception to a message box (or console)?

try
{
    // code that is failing
}
catch( Exception e)
{
    MessageBox.Show( e.ToString());
}

oyleiste

After a lot of googling, I found out that I should create a IRasterDatasetEdit3, copy first DTED's IRasterDataset to it and then, append other DTEDs using IRasterDatasetEdit3.Mosaic function. Here is my code's screenshot:
[ATTACH=CONFIG]23074[/ATTACH]

Unfortunately Mosaic(IRaster raster, double tolerance) function fails at run-time execution. I have no idea why. Does anyone has idea?
By the way, that's tolerance (second parameter) in Mosaic?!
Please guide me to this 😞

Thank you
Sincerely

Untitled.png

oyleiste

I think you are looking for a mosaic: http://resources.arcgis.com/en/help/main/10.1/index.html#//009t000000n6000000

Thank you Jason for your guide.
I think I should use mosaic but I tried a lot and couldn't use IRasterDataset which contains DTED Level 0; for mosaic.
The example code is so confusing also.
I think you can't use IRasterDataset for mosaic. Right?

JasonPike

Hello

I can get Linear Line of Sight from a single DTED file; which had beed opened by:
IWorkspaceFactory wsf = new RasterWorkspaceFactoryClass();
IRasterWorkspace rasterWS = (IRasterWorkspace)wsf.OpenFromFile(foldername, 0);
IRasterDataset rasterDS = rasterWS.OpenRasterDataset("n42.dt0"); //DTED Level 0 file
Single DTED file means that both observer and target are in the DTED file's area.

Well, the problem occurs when I load more than one DTED files and want to use these functions:
IRaster raster = rasterDS.CreateDefaultRaster();
RasterSurfaceClass rsc = new RasterSurfaceClass();
rsc.PutRaster(raster);
[INDENT]rsc.GetElevation(point);[/INDENT]
[INDENT]rsc.GetLineOfSight(blah, blah, blah);
[/INDENT]

If observer is in a DTED file and target is in another DTED file, GetLineOfSight function fails obviously.
How can I merge two RasterDataset to give rsc.PutRaster() function one single raster?
Or
How can I put more than one raster in RasterSurfaceClass?

Thank you
Sincerely

I think you are looking for a mosaic: http://resources.arcgis.com/en/help/main/10.1/index.html#//009t000000n6000000

You can find a code example here: http://help.arcgis.com/en/sdk/10.0/arcobjects_net/conceptualhelp/index.html#/d/0001000002z0000000.htm

Maximum seems like it would be appropriate for what you're doing:
"The Maximum method determines the higher pixel value from the two raster datasets that are overlapping."
http://resources.arcgis.com/en/help/main/10.1/index.html#/Mosaic_operators/009t000000n8000000/

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