Really great video, your channel is helping me to improve my ArcGis workflow and tasks. Would you explain the difference between Transformations, 1st, 2nd and 3rd oder, and when to use it, in which CAD drawing demands more control points? Greetings from Brazil!
When georeferencing CAD files you are limited to using only 2 points. ArcGIS, be it ArcMap or Pro, will not allow you to pick more than the 2 control points. So the software limits you to the affine transformation with a CAD file (DWG, DXF, or DGN). Raster files allow you to use as many control points as you desire. The more control points you choose, the more transformation options you have. The order of the transformation indicates the amount of change the software is allowed to apply to the image. A first order transformation will move (aka shift), rotate and scale an image. Where second and third orders will do all that plus skew or stretch the image. This link to the Esri ArcGIS Pro help explains this in much greater detail - pro.arcgis.com/en/pro-app/help/data/imagery/overview-of-georeferencing.htm Hope this response is helpful.
@@eGISAssociates Thanks a lot my friend, your channel has helped me a lot and your patience and attention to all videos question is really especial. Than you!
Great question. The difference between Update Georeferencing and Rectify is the output. Rectify generates a new raster dataset based on the applied transformation. Update Georeferencing writes a new world file or header for the existing raster dataset with the transformation applied.
It's really great! thank you for posting. Just a side question, I am working with a .dwg file and want 15 square boxes to measure 15 meters exact that is 1 meter/box. When I provide the scale factor of 0.0074 and the measurement was 15.26 meters which were close to the requirement of 15 meters. Any value above or below is resulting in the measurement changing drastically. How do we determine what scale factor value to use like if it depends on the Map scale or projection? If this scale factor is directly dependent on any other value of the data?
There are a lot of factors that can impact the distances you mentioned. In addition to the scale factor, it could be a unit conversion issue, ground to grid issue, the map projection and more. This is one issue with taking a 3D surface (the earth) and making it display in 2D. If that 15 meter grid measurement is the overriding requirement, I would suggest using the Create Fishnet tool to create the grid in ArcGIS Pro and then use that to georeference the CAD file too. That should maintain the distance of the grid. However other features maynot line up as a result.
Why when I open cad on arcgis map it's easy to deal with it but the same file of cad when I opened on arcgis pro it's very hard and heavy when I move on screen the drawing is disappear and appear
To georeference or transform shapefiles or geodatabase feature classes, ArcGIS Pro has a Conflaguration toolset which has tools to do this - pro.arcgis.com/en/pro-app/latest/tool-reference/editing/an-overview-of-the-conflation-toolset.htm
