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Dimitri


7,413 post(s)
#07-Jan-21 09:09

There's a new video on the videos page: 5 Minute Tutorial - Georegister a Drone Photo

This video uses exactly the same data as ESRI's "how to georeference a drone photo" tutorial given in an ArcGIS User magazine article showing workflow for ArcGIS Pro. That makes it easy to compare Manifold workflow with Arc workflow.

What's amazing is how much clumsier the workflow is in Pro. For example, the ArcUser article starts the workflow by prepping the image, assigning a projection the same as the target, etc. Here's a quote from the article:

"In the Contents pane, select EV_001.JPG, click the Imagery tab, and click Georeference. Notice the Georeferencing window in the upper-right corner. On the far left of the Georeference ribbon, click the Set SRS (for spatial reference system) button. Confirm that the Map XY coordinate system is NAD 1983 UTM Zone 10N.

Click Transformation and set the transformation from GCS WGS 1984 to WGS 1984 (ITRF00) TO NAD 1983. Click OK to apply and save again.

Get Ready to Georeference

In the map, right-click the Drone 4 Image Outline layer and choose Zoom to layer. Write down the scale visible in the lower-left corner.

Calculate two-thirds of that scale value (for example, if the scale at Zoom to layer is 3,000, then change the scale to 2,000)..."

No thanks! None of that is necessary in Manifold, as you can just import the .jpg and start adding control points to the drone image. :-) You can also georeference directly to a Google or other web served layer, or use a mix of vector and raster layers in a map (an upcoming video on georeferencing a map of Gettysburg will show that).

If anyone wants to compare Manifold workflow to ESRI, you should be aware ESRI has two completely different tools with different interfaces, slightly different nomenclature, capabilities and limitations, depending on whether you want to georegister raster images or vector drawings. If you want to georegister vectors, you have to use the "spatial adjustment" tool, which (to my taste) is even clumsier than the raster georeferencing tool.

dchall8
1,008 post(s)
#08-Jan-21 22:14

If you haven't clicked on Dimitri's link to the ESRI workflow, OMG, you have to. Just skim over it.

But on this topic, having the transparent preview and ability to edit the registration before committing is amazing. There were many times when I had to draw neighborhoods where the original drawing had no dimensions. The trial and error approach in M8 could be tedious.

julianclar
1 post(s)
#02-Dec-21 23:45

Thank you for

tonyw
736 post(s)
#11-Dec-21 06:06

That is slick in M9. In M8 one thing I ran into was the LiDAR images came as rectangles X pixels by Y pixels. The orthophoto however often did not fill the rectangle entirely and there were blank areas in the orthophoto. In M8 after georeferencing, if I overlaid the georeferenced image over a satellite image, the area with no image (the blank area) covered over the underlying satellite image and there was no smooth transition from satellite image to the georeferenced image. My solution was to reduce the opacity of the georeferenced image so the satellite image showed through. I would have preferred to see the georeferenced image at 100% opacity.

Is there a way in M9 to trim an image? I'm thinking not because images are rectangles. Perhaps a way to make pixels transparent? A long time ago I tried importing png but the transparency did not persist once in M8.

In the video example the drone photography went right to the edge of the image so the transition from satellite image to drone image was seamless.

geozap
264 post(s)
#11-Dec-21 06:55

You can't currently directly crop a part of an image using M9, and the software doesn't treat images by pixel. But you can use the triangulation registration method to do a crop.

Place control points in the image you want to crop, covering the area you want to keep. Save them as a drawing. Create a new blank drawing and open it. Select as source the image you want to register. Load the saved control points. Set triangulation as method and do the registration. You get a cropped image, inside (convex hull) the area covered by control points.

Dimitri


7,413 post(s)
#11-Dec-21 14:48

There's also this video.

"A short Manifold video that shows how to create a new image that is part of a source image. We often work with large rasters where we need only part of the raster, so we would like to get a copy of only part of the bigger raster in a smaller image. This video shows how. Using a large, four channel image of the region near Cheyenne, Wyoming, we clip out part of the image to create a smaller, three channel image showing a storage area in Warren Air Force Base. Works in the free Viewer, too."

BerndD

162 post(s)
#08-Dec-21 13:09

Now that is some fine example of great usability.

Well done.


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