Mesh with SRTMv3

José · Post by **José** » Sat Oct 07, 2006 1:52 am

Hi, Luis

Since NASA releases its SRTM version 1, in hgt format, things changed a lot. Now, one can download at http://www.csi.cgiar.org SRTM 90m Digital Elevation Data version3, for the entire world, as GeoTiff format.

I downloaded a mosaic and converted to BSQ format, to create a mesh in SBuilder.
In the hdr file, there are these informations:

BYTEORDER I
LAYOUT BSQ
NROWS 3600
NCOLS 3600
NBANDS 3
NBITS 8
ULXMAP -39.99958333
ULYMAP -3.00041667
XDIM 0.000833333333
YDIM 0.000833333333

I opened a new project in SBuilder but the image I saw didn't show the real area, but 4 similars squares, as below:

[img]http://www.ptsim.com/forum/uploaded/Jos ... 0areas.jpg[/img]

The bgl files were created but are not correct.

Could you please point my error?

Does SBuilder plan to support this new SRTM file format and convert to correctly to BSQ format?

Thanks in advance for any help,

Best Regards,

José

J.F.Lôbo

bassgeo · Post by **bassgeo** » Sat Oct 07, 2006 6:04 pm

Check out these settings in Global Mapper.
http://users.forthnet.gr/ath/bass/mesh.jpg
Panos

Panos M Georgotas

José · Post by **José** » Sat Oct 07, 2006 8:04 pm

It's just globalmapper I've used to convert to *.bsq file, but aplying the option you pointed, compatible with MS Terrain SDK (read text), Globalmapper generates a *.bil file, that cannot be read by SBuilder.

<i>"The raw data used when creating terrain for Flight Simulator 2004 must be in a binary file format, with each elevation point (measured in meters above mean sea level) being assigned a 16-bit integer."</i>

How should I proceed to get a *.bsq file that SBuilder read?

Is it possible to create only one *.bgl file for the mesh or SBuilder always create 1 km by 1 km *.bgl, as usual when working with *.hgt files?

Please, if you could, help me a little more.

Regards,

José

J.F.Lôbo

Horst · Post by **Horst** » Sat Oct 07, 2006 9:16 pm

Jose, as far as I remember.

You can use the BIL (16bit) with FS9 resample (see FS9SDK) direct to make FS9 mesh (DEM). Not sure about the “square pixel” option.

To set a bmp (map) up in Sbuilder (FS9) use the File/Dem Tool/Bsq to bmp to convert the bil file.
Use first row and colum and then the rest from hdr for calibration in Sbuilder.

I think, there is also a bounds option, when you do not want to use the whole geotif or ArcGrid.

Kind regards
Horst

PS:
To find the preprocessed tiles also Google is a nice help:
See:
http://srtm.csi.cgiar.org/index.asp
Download the kml file

The suitable SWBD data (need smoothing!) you can find here:
ftp://e0srp01u.ecs.nasa.gov/srtm/version2/SWBD

José · Post by **José** » Sun Oct 08, 2006 12:33 am

In 2003/november I and a friend released the mesh for Brazil, available at http://www.fsa.com.br/planobr2004/planobr.htm

At that time, we used *.hgt files from SRTM v1, and compiled in LOD 9 resolution (76 m) using a very usefull free program SRTMTOBGL.

I think it's time to make a revision, using SRTM v3, but compiling areas greater than 1km by 1 km, that seems impossible using SBuilder.

Perhaps we should wait for SBuilder new version, compatible with FSX terrain and new SRTM formats.

By the way, I download a shapefile in the website you pointed and I ask you if I can open the file directly in SBuilder, to modify the default FS9 shoreline.

Refering to the other website (google), unhappily I didn't understand what new things I could download from there.

Thanks for helping.

Regards,

José

J.F.Lôbo

Horst · Post by **Horst** » Mon Oct 09, 2006 5:54 pm

Jose,
The source STM Data V2, I think, are still stored in the same hgt format and the coverage.

But Cigar filled all the voids (spikes whatever) with contour line interpolation. And a bigger coverage, for one tile.

Outside US you will have 3 arc data.
Look to my link again.
(inside US and Canada, I would use NED and CDAD)

If you have the freeware Google Earth tool installed, you can open the small kml file.
You will see the the tiles (small point) you need for your area.
Klicking on the link will download the data you need
Of course, you can search also on the Cigar side.

SWBD is shp format. (and can not be compared to detail water data, i.e Navteq or other)
Currently not, but when you have a look to Luis new Sbuilder preview shot, there is also Append/shp.

But both data sets are a nice job, IMHO, in areas where you can not get better data.

If Sbuilder can handle GeoTiff, it will be nice.
As mentioned in the FS10 SDKs, most of the data are produced with resample (Fs10), are geoTiff

Kind regards
Horst

José · Post by **José** » Mon Oct 09, 2006 6:30 pm

Thank you very much for the explanation.

Best Regards,

José

J.F.Lôbo

Luis Sa · Post by **Luis Sa** » Tue Oct 10, 2006 9:13 pm

Hi,

I have to read the specifications about GeoTiif!!! I am working arount the "Map Tool". I am looking to a way to automatically catch a map from Google or Yahoo and get it well placed in SBuilder.

Luis

José · Post by **José** » Wed Oct 11, 2006 2:31 am

Hi, all people

Did anybody get mesh file compiled with MS resample.exe, using srtm v3?

I tried, but I got so many spikes in the area or no mesh at all in the *.bgl created.

I am converting the srtm *.tiff files to *.bil, using globalmapper (or dlgv.exe - the same as globalmapper, but free).

Thanks for any help or hint,

Regards,

José

J.F.Lôbo