Hi Guys, I need help in building a spatial index of Aerial photos and have the Image Service project on the fly. Appreciate any ideas or inputs from anyone who has knowledge about this.
Thanks in advance.
- Jessiecar
Jessiecar,
Have you tried the Add Spatial Index geoprocessing tool?
Add Spatial Index—Help | ArcGIS for Desktop
Spatial indexes are for featureclasses (see An overview of spatial indexes in the geodatabase—ArcGIS Help | ArcGIS for Desktop ).
If you have an image service, your raster data will probably be in a mosaic dataset. In a mosaic dataset you will create overviews (Build Overviews—Help | ArcGIS for Desktop ) and there are other tools available to enhance the performance of the mosaic dataset (see also Add Rasters To Mosaic Dataset—Help | ArcGIS for Desktop and other tools in the Mosaic Dataset toolset. You can load the raster and they will be projected to the configured spatial reference.
I didn't tried it yet just like what Xander mentioned, it says that "Add Spatial Index" is for shape file, file geodatabase, or enterprise geodatabase feature class.
But thanks, I might try exploring it too to see if there's something I could use it for.
Hi Xander, thank you, I will try this and you are correct that I have Mosaic Dataset but it only contains those georef images.
So if I will be adding those non-georef images on my mosaic dataset, there is a way I could have those projected on the fly? I have a metadata for all Aerial photos that I have - both georef & non georef images.
Thank you so much for your time.
non-georeferenced images still need georeferencing, otherwise their place is space will remain unknown and cannot be appropriately integrated with georeferenced data
Thanks Dan.
Do you know any way to georeference by batch? Doing it one by one will take forever and that is not feasible to the project I am working with.
Much appreciated. Thanks!
Hello,
If you Aerial images are well processed(georeferenced , orthorectified ) then you are able to create spspatia lndexes and view to use in further analysis.
In ArcMAP not seen or use batch Georeferencing tool.
Thanks.
Hi Avinash, unfortunately, I have Aerial images that are not georeferenced.
The georeference information is available as the metadata for all Aerial photos I have - both georeferenced & non-georeferenced images.
Here's a sample screenshot of an Aerial Photo that is not georeferenced.
Will try to use Phyton code in georeferencing by batch.
Thank you Xander.
Another problem I have here, as you can see on the sample image, the GCPs is not the current extent of the Aerial Photo. It require cropping before I can proceed in georeferencing by batch using Python code.
Any other inputs related to this, I would appreciate.
Thanks everyone!
Hate to tell you, but you are looking at a lot of manual labor...
That's a really old style aerial photo. Don't see many of them around these days. Xander is absolutely correct, there is no one click solution to get these geo-referenced easily.
But have you considered using more modern sources of aerial imagery. Or do these photos have some sort of historical interest?
You are right Neil, I need historical Aerial photos along with the recent ones. And I don't have problems with recent coz all of those are georeferenced.
That's what I'm trying to resolve Xander, finding a possible solution to not do a lot of manual work.
Good news. Me and my team were able to find other resources like gdal & metalab to do cropping of aerial to have the GCPs as the extent of each Aerial photo.
From there, once the Aerial photos are cropped, we can georeferenced these images by batch using Python or other script.
Thanks everyone for all the inputs.
Hi Jessiecar Esguerra , I don't want to ruin your day, but I don't think that it will be possible. Cropping the images in batch is no problem. What really is the hardest job is to find the control points and align the raster with these control points. See Fundamentals of georeferencing a raster dataset—Help | ArcGIS for Desktop
How are you planning to use a python script to do that part of the job?
HI Xander, I have the metadata for all my Aerial Photos which contains all the control points. I can use the image filename to link with the metadata and then assign those control points programmatically.
That is good to know! In what format are the control points stored? And how are they defined (rows, cols and related coordinates)?
For the control points I have two formats available in the metadata, the DMS & Decimal Degrees.
But, how do you know where in the raster image (pixel position, row & col) these control points are located?
The Aerial photo's filename is also included on the metadata.
Using the filename, I could identify what are the control points for each from the metadata.
Can you attach an example of the Metadata for an aerial photo? Just to know what your possibilities will be...
Sure Xander.
See attached screenshot containing a sample metadata for an Aerial photo. I tried attaching an excel file but I can't here.
The corner correspond to the fiducial marks? Are these always in the same location (row, column in the digital image)?
I very much doubt it. These are photos later scanned to get them into an image file.
The pixel coordinates will depend on the position through the scanner.
I very much doubt there will be any correlation between pictures as to the exact pixel locations of fiducial marks.
However, you do seem to have the picture centre in Lat/Long. Perhaps something could be engineered out of that.
I have my doubts too, but with some numpy executed on corner rectangles with a certain extent, i think these marks can be identified and can be tied together with the metadata. Would be interesting to try this...
Thanks everyone for all your input and feedback.
We have actually tried a few photos and it was georeferenced on the right location though there's a slight misalignment which I think is expected since these are Historical photos.
Great to hear that!. Can you elaborate a little on how you did this (manually, or with script)?
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