Rubber sheet software to stretch/geo-reference image
Posted 29 March 2007 - 07:08 PM
For instance, this map: http://mapmaker.rutg...APS/NJ_1795.jpg
I could click on, say, 16 points, a square box of 4x4 points, and set lat/lon pairs. Then I could transform it to WGS1984 projection so that I could make a tileset out of it and load it over Google Maps. Of course this is not exact - but I imagine it would be close enough to get the desired result.
Posted 29 March 2007 - 09:02 PM
Well I have ArcGIS 9.1, but my help file never installed properly! What is the process or tool called? I'm not used to working with raster in ArcGIS, only vector.
Go to View>Toolbar>Georeferencing. You need to fix that help file! This will set you in the right direction: Georeferencing a Raster Dataset
Posted 04 April 2007 - 01:43 PM
In particular the georeferencing allows you to set vectors for stretching the image. As a layer in your map, these are retained and your image will georeference on the fly as you use the map--for large images, this can be slow. Thus, another option is to rectify the image, which is really saying write a new image file based on the transformation and stretching vectors you've specified.
If you don't know your image's coordinate system, there's not much of a way to project it a known projection without some problems. There is a raster project tool, which will project a raster of a known coordinate system to another coordinate system; and there is a tool called define projection, which will assign a coordinate system to a dataset.
Closely related, we added some new raster layer functions at 9.2, one for on the fly orthorectification, as well as on the fly pan sharpening. We also did a on the fly hillshade, but I haven't found it useful for making maps.
Erin pointed out that the Web Help is available, though note that the search engine is different and a little inferior to the one we started using for the Desktop Help at version 9.2--which is by far the best we've ever had.
Another resource would be our functionality matrix, which lists the function an the licensing level--sadly I didn't know we even had such a thing until this morning.
PDF Brochure/Poster view:
PDF letter size text table view:
here is the 9.1 version (just in case)
Software Products Department
ESRI, Redlands, California
Posted 11 April 2007 - 10:58 AM
I am super impressed... and considering switching from the Google Maps API to the Virtual Earth SDK as my main web platform.
Posted 12 April 2007 - 07:56 AM
Posted 12 April 2007 - 09:48 AM
That is actually how I am doing it right now - I am using the georeferencing tools to get the image nicely aligned (which is easy, only needs two points) - then I get the coords for the upper left and bottom right corners, and feed them into an excel sheet. The sheet (attached) is set up to automatically calculate the world file, which I paste from excel to a text file. I just thought there was a smoother way.
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