Need Help with Geo-referencing of Raster with Bentley Descartes

hey thanks Mathew 4 all ur help especially ur video....l was able to georef. d image...bellow is hw i went about it Procedures taken 1, the image to be georef was at the origin position of the design plane 2, i used the nothings n eastings positions of (740500N, 533800E & 740500N, 541800E, & 737500N, 533800E & 737500N, 541800E) points on the image to geo ref 3, So i placed a rectangle around those positions on the design plane (distance frm origin) 4, then i used the Descartes registration model to register the image to those 4 points vertexes on the rectangle 5, i resampled the image, creating a new georef image with d world file option 6, i detached the original image and attached the georef image to d view 7, the attached georef image was at another position, so i had to move it the correct position(position of the rectangle, thereby completing the georeferencing process thank you Mathew for evrytin.....but there are still questions i wanna ask quests are - the image had already been vectorized before this georef process.......i hav georef the image(thereby causing a change in location and size) but the vector data didnt georef wit d image, it is still at the normal position and size. Is there a way to still georef it? cos i tried manually scaling and moving it to d position of the rectangle but it aint fitting properly…or hw shld I go about it -anoda question is dat, i used the 3pts or + affine model to georef the image and it appeared properly.....but y is it dat wen i used the 4pts or + projective model to georef the image, its gave me a blank image, seeing no image -also pls you hav seen d process i used in georef the image, is the a better way to go bout it?, wanna ask u if u have ideas improved ways of goin bout a procedure, or if u hav some tips on hw beta to get done…even if its just one or two thank you again Mathew 4 ur help Regards Dipson

Hi Dipson,

First I find it strange that the geo-referenced image was not located in the rectangle after the registering process. Maybe sister file created was not used according to your Raster Manager related preferences?

Descartes can only geo-reference images. But according to your coordinate you should be able to use standard MicroStation moving and scaling tools to position your vector and your raster correctly without using Bentley Descartes' register tool.

Here is an video showing how to place your raster with some vector on it using standard MicroStation move and scale tool :

Finally for the blank image the 4pts or + projective requires that at least 4 pair of points linearly independent (e.g. : not co-linear) be specified. But according to your coordinates using a projective transformation is not recommended. A 2 pts or + similitude transform should do the trick.

HTH,

Mathieu