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Geoprocessing Tiff Files

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#1
Benjaminbunny

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Hi Guys

I am new to this forum so please excuse any basic mistakes!

We currently are working on Geoprocessing a series of raster images in order to digitise over the top. This is being undertaken using Arc 9

Some images are in JPEG format and once geoprocessed a world file is created.

However, when doing the same process with Tiff files the world file is not created....

could someone explain what exactly is happening - the end user requires the world file so we need to create it somehow

#2
Hans van der Maarel

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We currently are working on Geoprocessing a series of raster images in order to digitise over the top. This is being undertaken using Arc 9

Some images are in JPEG format and once geoprocessed a world file is created.

However, when doing the same process with Tiff files the world file is not created....

could someone explain what exactly is happening - the end user requires the world file so we need to create it somehow


I'm not familiar with Arc myself, but if there is no option to write a world file, you can use GeoTiffExaminer to create a world file out of the GeoTiff.

Hope this helps.
Hans van der Maarel - Cartotalk Editor
Red Geographics
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#3
Kalai Selvan

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Hi Guys

I am new to this forum so please excuse any basic mistakes!

We currently are working on Geoprocessing a series of raster images in order to digitise over the top. This is being undertaken using Arc 9

Some images are in JPEG format and once geoprocessed a world file is created.

However, when doing the same process with Tiff files the world file is not created....

could someone explain what exactly is happening - the end user requires the world file so we need to create it somehow


Hi Benjamin,
With your query i understand that you are trying to geo-reference the jpeg,tiff files correct.
In arcgis, when a scan of any supported format is geo-processed, as a note of success it delivers a TFW file correct, thats what you are referring as a World file. If your input is tiff, there shouldn't be any problem for you to get a world file.
May be your are missing out something, just try the same process what you have adapted for jpeg and don't forget to set the destination path where you want your tfw to be stored.

Just try & let me know, if you still have problem i shall assisst you.

Regards,
GISGURU.

Thanks and Regards
Kalai Selvan


#4
Adam Wilbert

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Without trying it myself, I would guess that its because the localization data is contained within the geotiff file itself. There is no "GeoJPG" standard that I'm aware of, so they require the external world file. But by adding coordinate information to the header of a boring old regular Tiff file, you get a happy geo-located and self-contained GeoTiff.

Adam Wilbert
CartoGaia.com & AdamWilbert.com
Lynda.com author of "Up and Running with ArcGIS"


#5
Unit Seven

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Getting world files out of Arc is a bit frustrating at times. ESRI tend to use their own aux file instead of a tfw. This aux stores projection information as well as the coordinates which I guess was one of the shortcomings of tfw.

Are you getting this aux? If so there are probably scripts out there to create a tfw—if you find one can you please let me know. I haven't really looked but could do with one.

Cheers,

Sam.
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#6
Benjaminbunny

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Thanks Guys!

I'm going to have to play around with your suggestions and let you know how I get on.

I've not been actually Geoprocessing myself (yet) but as far as I am aware the process used is exactly the same regardless of jpeg or tiff - but I will double check this.

So I'm not sure yet what files are being created - I'll have to wait to get access to the data first!

#7
klacefield

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I did some quick experimenting around with georeferencing a tif file within ArcMap and came up with the following information which may be helpful.

I used the Georeferencing toolbar within ArcMap to successfully georeference a tif image and created a world file. The key is to use "1st Order Polynomial (Affine) for your transformation. You will need a minimum of three points to do this. The reason for this is that a world file only stores first order transformation or affine transformations. If you are using anything else besides these then ArcMap will not create a world file (as that is not supported within the world file) and will only create an AUX file.

My recommendation is to try to georeference your image again using ArcMap's Georeferencing toolbar and make sure you use 1st order polynomial. then click on the "Update Georeferencing" option and see what happens. You should have an aux and tfw file created.
Kevin Lacefield, GIS Programmer Analyst
County of Sonoma
Information Systems Department - GIS Central

#8
Kevin McManigal

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Another thought,

In Arc, with only your referenced tif visible, try the "Export Map" function, choose tif, and check the create world file box.

Good Luck,

Kevin
Kevin McManigal
Orange Peel Cartographic
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