FSXA Exporting GeoTIFF lat/long

[Kack911]

All,

I'm working on a large airport scenery, and for my airport background, I used very high resolution aerial imagery applied to 3ds Max planes with a flatten underneath. The result is very convincing, but I'm faced with some very serious limitations that I don't think I can live with: Mass Autogen exclusion for miles around my objects, and incorrect fogging during low visibility conditions.

As such, I would like to switch to the FSX Photoscenery method, but I'm woefully behind the knowledge curve. Can someone please shed some light on this for me?

I have a large .SID image created by the State GIS gurus. It is for the entire county, and is 1.4GB in size. There are also a series of related metadata files with file extensions of *.AUX, *.SDW, *.SID.AUX, and *.SID.

By looking in these files, I see the pertinent data that describes the Projection, Datum, Central Meridian, Latitude of Origin, Resolution, etc. However, no matter what program I load it into, it will not show me the actual lat/long position of my cursor. I only get "reference units" which in this case is "feet".

I'm using the MrSID viewer to select a bounding box around my airport, then export my selection as a GeoTIFF. But when I select my bounding box and export, it does not generate any metadata, and I have no idea how to properly georeference the resulting image. As a result, my image is useless as far as SBuilder is concerned.

I attempted to load the entire county image into SBuilder as a last resort, but the file is apparently too large, as it either hangs up, or tells me the image isn't valid.

Does anybody see where I'm going wrong? I've attached the metadata files, in case it helps diagnose the problem. Is there a specific program anyone can recommend that will create GeoTIFFs from a larger georeferenced image?

Thanks for any help you can give!

Nick

 

[LCSims]

MrSID files are highly compressed and your 1.4 .SID file translates into approx. 42gb worth of GeoTiffs. Even if SBX could read the file, I think it's easy to see why it couldn't load.

You would need a commercial tool to work with the file, as the freeware approaches are hit and miss. Rather than bother with the SID file, I would suggest using the USGS Seamless server to see if they have imagery for your airport area. Some (many?) times they have the GeoTiff files that were used to make the SID. Download pieces are limited to 250mb, which can be bad and good. Bad, if there are many files for your desired area. Good, if you would want to do some color correction work. Most image editors will start to choke on very large files. The GeoTiffs from the USGS probably won't be in the preferred projection/datum for FSX, but there are freeware tools to change that for you.

 

[Kack911]

Thanks, unfortunately, the state imagery data is not available on the USGS seamless server, and the data that is there is not of the quality needed.

When I export only the area around my airport, the TIF file size is just over 1Gb. Once I split that up into the 2048x2048 tiles and compress to .dds, the total file size for all of the background imagery is only 277mb at 1ft/px.

That being the case, I'd think that SBuilder could handle it. How do people do large scale photoscenery of entire states if I can't load a single county, or worse, even a single airport?

Nonetheless, My first hurdle is to figure out how to properly GeoReference my existing TIF image. E-mails to the State GIS people have gone unread apparently, so that's why I'm posting here.

Thanks again.

Nick

 

[LCSims]

SBuilderX won't work with a DDS file. BMP or GeoTiff, yes.

The INF file can contain references to many "source" files and combine them into a singular BGL file.

I just looked at the Seamless server and it's line of goodies. Not knowing the particular airport, but using Dayton - KDAY as an example, the server has 1' (.3048m) imagery from August, 2005 available. Using a small square area of 39.95x-84.27/39.85x-84.16 produces a download size of 3,542mb. You can see how it would need to be broken down into even smaller bites.

The source from USGS comes in UTM/NAD83 format, which needs to be changed to Geographic/WGS84, but there are tools that will do that.

So if you want it, there it sits. Just a little more effort at the ultra friendly USGS site will yield results for you.

And people that do statewide imagery have a ton of patience, because those long drawn out compiling times can be a drag...

 

[Kack911]

I certainly appreciate the time you've taken to respond to my question, thank you. Unfortunately, I'm not getting the answer I'm looking for...

The data on the USGS server is not of the same quality as the downloadable OSIP data from the Ohio GIS website, and it is several years older.

What I'm really asking here is, how do I take a large county-wide GeoTIFF, and export only an airport-sized portion of it that is properly georeferenced and ready for use in SBuilder or for ANY program capable of creating photoscenery for FSX?

Please understand that I'm not trying to be an ass or anything, I just have way too much time invested in the current imagery to just start over.

Thanks again.

Nick

 

[hcornea]

I have only seen payware commercial tools that do this. The tool I use is called Globalmapper.

It will read Georeferenced files in a number of formats and projections, and can export as much or little as you like.

The demo version does not export things from memory, but you could try it out to see whether it is likely to be worth the price of admission.

SBX will read small Geotiff files, but runs out of memory pretty quickly.

 

[LCSims]

I agree with hcornea that Global Mapper offers the best option. New purchases can be found for around $280.

Or if you'd like, PM me with some coordinates and I'll see what it looks like. You are referring to the 1 foot source and not the 6 inch? The compression for the 6" would probably make it no better than the 1', IMO.

 

[Kack911]

Thank you both. I'll take a look at Global Mapper.

I was able to load the saved imagery using the LizardTech GeoViewer, but I found the same problem as before - that my cursor coordinates were in feet from a reference datum, and it was not able to determine lat/long. I tried connecting to the Ohio GIS website to work directly from their WMS server, but the data for Montgomery county is not there... not sure why. So I'm stuck using the downloaded data.

LC, the airport in question is, in fact, Dayton (KDAY). I downloaded both the 1ft and 6inch data, and you're right, after looking at both in the viewer and in the sim; the 6inch data was HUUUUUGE and it didn't look any better.

If you're really feeling charitable, and you'd like to take a glance at the imagery, it can be found here:

http://gis3.oit.ohio.gov/ZIPARCHIVES/IMAGERY/1FTSIDMOSAIC/Montgomery.sid.zip

Or, if you want to try the WMS server, it's here:

http://gis1.oit.ohio.gov:80/wmsconnector/com.esri.wms.Esrimap/osip?

Thanks for your input, and I'll take a look at the software you suggested.

Regards,

Nick

 

[LCSims]

I can neither confirm, nor deny that I'm familiar with the OSIP site...

Depending upon the cutting, the file size runs from 750mb to 1.3gb +-. If you're planning to do blendmask on the area, then you must work in smallish chunks, as no photo editing software that I am aware of will work with a 1.3gb file. They may, but I'm not that well versed in the area.

I can do some cutting of smaller files and upload them ready for running through a photo editor or the SDK compiler.

 

[Kack911]

Thanks LC.

It's going to be a payware project, so I wouldn't ask anyone to do any work for me. I just thought you meant you'd look and see if the data was usable by Global Mapper or not. Sorry for misunderstanding.

As it turns out, running Win7 64bit on a Quad Core (Q9650) with 8Gb of RAM allows me to work on the 1.3Gb image with relative ease using the 64bit version of CS4. I already did the alpha masks and whatnot...I found that working with smaller chunks created nasty seams that ruined the gentle fade-in I was going for. So I opened the whole image at once, and didn't do the slicing until after the alpha mask was done. Worked like a charm.

Thanks again for the offer, though. I'll probably take a leap and get Global Mapper in the hope that I can make it all work in the end.

Regards,

Nick

 

[scott967]

I'm assuming your SID data is in State Plane Coordinate System for Ohio, which of course you need to reproject to Geo. It's probably also using NAD83 datum, but that's no issue as there is no datum shift to WGS84. Global Mapper can easily do the reproject, and tile your output if you want. The one thing is I think that the SID libraries are proprietary and in the back of my mind I think there might be limits on how big a file can be handled. I would send them an email before buying, or subscribe to their support email list (the guy who runs it "Mike" usually answers questions within a day).

I think they jacked up the price of GM 11 a bit (probably worth it if you are going to do this much). I'm still on GM 7, just can't justify the annual upgrades for my FS hobby (though I do some work for my wife's real estate sales biz, to be honest GM 7 works fine for that).

scott s.
.

 

[hcornea]

GlobalMapper11 offers a 64bit native version, which is the only thing tempting me, but I agree - I'll stick with Globalmapper 10 - the update is not especially good value for me.

I'm almost certain Globalmapper will do what you want - and much more.

As a guide, it is quick and easy to create vector information and export in SHP over the top of your imagery, then run through SBX or SHP2Vec

 

[Kack911]

Thanks guys, some truly helpful suggestions. I went ahead and took the plunge and got GM11.

Indeed, the imagery is in the Ohio State Plane South datum, which, after converting the supplied *.sid.aux files into plain text (vice XML), was automatically read by GM. The imagery is looking great, and seems to be properly oriented and aligned. Next step is to work on exporting the airport bounding box, and redoing my alpha masks.

I'll probably be back when it comes time to get everything loaded into SBuilder correctly. In the mean time, I truly thank you for your help.

Regards,

Nick

 

[hcornea]

In terms of loading into Sbuilder - that couldn;t be easier.

Export as a Geotiff (WGS84)

Add map from Disk, select Tiff and SBX reads the Geotiff information.

Only problem is there is a size limit.

 

[Kack911]

H,

I spent a few hours last night working through the process, but in the end, the only imagery I was able to get into the sim was from the VE server.

First and foremost, when I reproject my imagery into the Geographic/WGS84 format, it's pretty distorted. It looks stretched horizontally (or squished vertically...I'm not sure which.) Is this normal? Does SBX/FSX account for this?

After exporting my GeoTiff from GM11 in Geographic/WGS84 projection, I was able to "Add a Map from Disk", but it only read the latitude correctly...the Longitude was totally wrong, so I had to manually give SBX the boundary lat/longs. I also couldn't edit the x or y pixel dimensions, which differed from the metadata generated by GM.

Having done that, and with the imagery appearing to be properly positioned in the World Space (although distorted), SBX refused to compile it. I mean, it didn't even try.

If I follow the available tutorials, and try to add a map from the background, that option is grayed out. If I select my image and click the export button, all of those options are grayed out too. I renamed my image "Photo1.tif" and placed it in the "Work" directory, but that didn't help.

Just to see if the program was setup correctly, I downloaded data from the VE server, and was able to export that without any issues.

Any idea what I'm doing wrong?

Many thanks,

Nick

 

[rhumbaflappy]

2 things come to mind.

The geotiff may not actually be geographic projection with WGS84 datum.

Or, perhaps the image is so large that SBuilderX won't try to process it.

Your 'SBuilderX313\Tools\Work' folder should contain an INF file for the image... you might post that... or manually run it with resample.

I suspect the case is that the geotiff is the problem. Global mapper should allow you to save a prj file and a tfw file with your saved geotiff export. Posting the contentss of those files might also resolve this.

Also, what is the image size in pixels?

Dick

 

[Kack911]

Dick,

I was able to run the "calibration" routine in SBX, which seems to make up for the fact that SBX isn't correctly reading the GeoTiff's data. The image is now displaying without obvious distortion, but I'm still unable to compile anything. The "Photo Scenery" box in the Compile screen is still grayed out.

I've attached the two world files generated by GM. They don't seem to contain the same data as the original GeoTiff that I was working with. I don't see anything about Central Meridians, Latitudes of Origin, bounding Lat/Longs, etc.
They only seem to contain a single Lat/Long, and some projection datum info...

I've also included the Data file generated by SBX after running the Calibration routine. Maybe that provides some more insight.

The exported .TIF dimensions are 17322 x 16695 pixels, and its 123MB. SBX loads it, and displays it just fine, and I have no trouble working with the image or navigating around with it displayed. And just to re-iterate, SBX isn't even attempting to do any compiling, so I'm not getting any error messages or compiler errors. It simply claims that I don't have any objects selected for export, even though I clearly have my map selected.

I'm positive I'm doing something wrong (obviously), but the available tutorials don't seem to cover adding maps you have stored on your disk. I guess streaming data from a server is the preferred method...

Thanks for the help.

Nick

 

[LCSims]

First thing I would do is go back and reload the SID file into GM11, reproject and correct the datum, then export the file coverage area. Otherwise you get the twisted mess that you describe for an image.

I tried to add a GeoTiff into SBX and it wouldn't compile a file. In last year's update it is possible this procedure got broken? Or, never having tried to compile a GeoTiff through SBX, I might not fully understand the process.

Once you have the files out of GM11 it's a simple process to build your own INF file and manually compile the files. Just remember to tick the Create a TFW file area, as that gives the Lat/Lon to go into the INF file, along with the Xdim and Ydim. Matter of fact, if it's a GeoTiff file the INF file doesn't need that information. You would need it for your blendmask Tiff file.

 

[Kack911]

Hi LC,

I've gone back into GM and reprojected and re-exported several times. All with the same result. Upon loading into SBX, it insists that I need to recalibrate the image. If I don't, it displays a distorted image at about 38N 9W instead of 39N 84W...

If I choose to recalibrate, then it displays properly. I checked the alignment using the "background view" from the VE server, and it lines up exactly as it should.

That leaves me at the point where SBX refuses to acknowledge that I ahve selected my map for export. It insists that there's nothing to export.

I've been combing the web looking for a generic .inf to use to try and manually compile, but I'm not having much luck. The Millenium example in the SDK doesn't look anything like the one I found in "hcornea's tutorial", and I'm not really sure what teh content of the file is supposed to be.

It would certainly be a plausible explanation if the GeoTiff functionality were broken. It certainly seems like the preferred method is to use streaming servers...

I'm crossing my fingers that I'm just doing something boneheaded and that I can get it figured out.

Regards,

Nick

 

[rhumbaflappy]

Hi Nick.

The prj file seems OK. Maybe you are overthinking this...

Make an INF file:

[Source]
Type                = GeoTIFF
SourceDir           = "."
SourceFile          = "test.tif"
Layer               = Imagery
Variation           = Day
NullValue           = 255,255,255

[Destination]
DestDir             = "."
DestBaseFileName    = "Test"
DestFileType        = BGL
LOD                 = Auto

Name the file as test.inf... and replace the geotiff name as the 'SourceFile'.

Place the image and the inf and a copy of resample in the same folder, and drag'n'drop the INF onto resample. If the image is a valid geotiff , and the right projection, it should compile. It gets the right Source bounds from the image-embedded geotiff info.

If this works, then you can customize the INF file. Maybe the NullValue needs to be black:

NullValue = 0,0,0

You can add 'Destination' bounds to get a smaller area output.

NorthLat = ?.???
WestLon = ?.???
SouthLat = ?.???
EastLon = ?.???


In that way, you can get a small rectangular area from a large image. Also, Global mapper allows you to define a smaller area from it's saving routine.

Dick