Coordinate transformation of image file

[nomisc]

I have a satellite image file originally created with WGS 1984. I need to use it in a drawing with British National grid co-ordinates. In Arc I redefined the projection to British grid, but when I import it still comes in using the WGS co-ordinates and is consequently in completely the wrong place. I've looked at various threads, but all seem to deal with drawing or vector data rather than raster. Any help most appreciated.

[Pointdump · Accepted solution]

Nomisc,

When you bring in a geo-referenced image with Data Connect, check to see if it's in its original Coordinate System, the one in the World File or PRJ File. Don't change it. Map 3D will automatically convert it to whatever Coordinate System you're using.

Dave

[antoniovinci]

Sounds like you did not correctly transform the image from Wgs84 to the destination CRS: would you please share it with us..?

@ DAVE 

A geo-referenced image needs neither any Worldfile (because it already contains the geo-header) nor any .PRJ (concerning vector shapes only)...

[nomisc]

Hi Dave,

Brilliant, sorted.

I thought it would probably be simple, but that's great.

Thanks

[Pointdump]

Antonio,

OP said he "redefined" the image. The only way to see if it's still in its original coordinate system is to look at the World File or PRJ or sometimes there will be an XML File tagging along.

I haven't had much luck bringing in an image if it doesn't have a World File with it, but I will defer to you on this one, because you have infinitely more experience in this than I do.

Dave

[nomisc]

Hi folks,

I spoke too soon, as although my relatively small satellite image (560MB) will load, the larger (c1.5GB) files won't. I either get an error "Failed to connect" or else an error about "...writing to read only memory that suggests the memory is corrupt" or something similar. Either way I suspect this will be an issue to do with the file size and remote data connection. Isn't there some way I can just use the "Import Image" function, but with a different co-ordinate system?

As you'll have seen I'm dealing with images that I can't easily send you copies, sorry.

[Pointdump]

 Nomisc,

Wow! 1.5GB? That's a huge file. And 560MB is the "small" image? I usually use Aerial Images that are considerably smaller, so I'm not sure if there is a file size limit. Have you tried loading the image using MAPIINSERT?

As for posting large files, DropBox works very well for posting large files. It's easy and free.

Perhaps Antonio will weigh in again. He is the undisputed King of Geo-Ref'ed Images.

Dave

[nomisc]

Hi Dave,

Unfortunately it's because MapInsert doesn't work that I was looking for an alternative. I have an image file in OSGB that loads happily into ArcGIS and GlobalMapper, but when I import to AutoDesk it's massively mislocated. Here is the metadata from within GlobalMapper

FILENAME=D:\Satellite\6060\00Study Areas\UK1\4band_234_OSGB_1.tif
DESCRIPTION=4band_234_OSGB_1.tif
UPPER LEFT X=619509.741
UPPER LEFT Y=238511.919
LOWER RIGHT X=625257.113
LOWER RIGHT Y=232677.538
WEST LONGITUDE=1.19422469° E
NORTH LATITUDE=52.00089439° N
EAST LONGITUDE=1.28153986° E
SOUTH LATITUDE=51.94622228° N
PROJ_DESC=British Grid / NAD83 / meters
PROJ_DATUM=NAD83
PROJ_UNITS=meters
COVERED AREA=33.532 sq km
NUM COLUMNS=18165
NUM ROWS=18440
NUM BANDS=1
PIXEL WIDTH=0.3164 meters
PIXEL HEIGHT=0.3164 meters
BIT DEPTH=8
SAMPLE TYPE=Unsigned 8-bit Integer
PHOTOMETRIC=Palette-Color
BIT_DEPTH=8
SAMPLE_FORMAT=Unknown Format (0)
ROWS_PER_STRIP=1
COMPRESSION=PackBits
ORIENTATION=row 0 top, col 0 lhs
PIXEL_SCALE=( 0.3164, 0.3164, 1 )
TIEPOINTS=( 0.00, 0.00, 0.00 ) --> ( 619509.741, 238511.919, 0.000 )
MODEL_TYPE=Projection Coordinate System
RASTER_TYPE=Pixel is Area

Those UPPER LEFT co-ordinates etc are correct for its location on the OS grid, but for whatever reason AutoDesk doesn't seem to recognise them.

I'll see what Antonio suggests.

Thanks again.

[Pointdump]

Nomisc,

OK, so what Coordinate System shows in the FDO dialogue box?

Dave

[nomisc]

It shows BritishNatGrid, but that's not the problem as this file loads okay using the Data Connect. It's when I use MapInsert it doesn't and as I've already discovered the larger files won't load at all through DataConnect. Maybe I'm just trying to do something no-one else does, but I find that hard to believe.

Cheers

Simon

[Pointdump]

Simon,

So DataConnect won't load it and MAPIINSERT mislocates it. Puzzling, but we just have to find out where it's breaking down. OK, so when you bring in the big file with MAPIINSERT, do an inverse and figure out how much it's mislocating(direction and distance). That might help to discover the problem.

As for why DataConnect won't load the file, it might be the size. Dunno.

Dave

[nomisc]

Hi Dave,

Sorry, I'm not quite sure what you mean by "do an inverse" or how to do it.

[Pointdump]

Simon,

I meant how far away, distance and direction, is the mis-location? The reason I ask is because of another problem I saw, where the Lats and Longs in one drawing were being converted to Northings and Eastings in another.

Your image has NW Corner/SE Corner of:
WEST LONGITUDE=1.19422469° E
NORTH LATITUDE=52.00089439° N
EAST LONGITUDE=1.28153986° E
SOUTH LATITUDE=51.94622228° N

Where is it ending up? Where are the Corners after mis-location?

Dave

[nomisc]

Hi Dave,

The south-west corner is c2.4390E+07, 9160537.4125 and the north-east at c2.4616E+07, 9390231.3121 which is massively out of position. Interestingly, although it is a geotiff and you've seen the metadata, when I import it AutoDesk thinks its just an mage file (see below)

I guess that may have something to do with it as the insertion values are very similar to the final position. The problem is to know what to use. I tried 0,0 instead, but that didn't work either. I could try and work out where it should insert, but surely that is defeating the object of having a geotiff.

I'm off for the weekend now. Thanks for your help so far.

Simon

[Pointdump]

Simon,

Are your AutoCAD Drawing Units set to "Inches"?

(24,390,000)/(39.37008)=619,505.98
(9,160,537.4125)/(39.37008)=232,677.6428

Dave

[antoniovinci]

---

nomisc wrote:

PROJ_DATUM=NAD83

---

Well, I was aware that NAD means "North America Datum", whilst seems like we're talking about England, aren't we?

@ Nomics 

What happens if you load (_MAPIINSERT or _MAPCONNECT) my attachment..?

[nomisc]

Hi Dave,

Right, we're getting there as it puts it in almost the right place,

....but not quite. The OS map base is correctly referenced and the SW corner is 620000, 235000. I can use ALIGN from here, but again this is defeating the object of what the in-built geo-referencing should be doing.

I still don't understand why.

Cheers

Simon

[nomisc]

Hi Antonio,

Thanks for that. You'll have seen above that I had an error having my defalt units set to inches which has got me closer, but not quite. I imported your file and it seems to be in the correct position

The question is what do I need to do to mine?

Cheers

Simon

[antoniovinci]

I assembled my scratch image basing on your metadata - unfortunately I cannot help better, without having your 4band_234_OSGB_1.tif...

Anyway, let's do another test, so please load in Autocad the following attachment: how does it fit..?

If fine, maybe I'll have an insane idea to solve this issue, sir.

[Pointdump]

Simon,

Here in the Colonies, that positioning error would suggest the difference between US Survey Feet and International Feet. But you're using Metric Units, right?

Dave