topic Raster output not snapping to raster in LIDAR Resources Questions

Raster output not snapping to raster

LauraDeming — Sun, 05 Apr 2020 20:57:08 GMT

Hello,

I am working in ArcMap 10.7.1 with 1-m resolution lidar (hydro-flattened DEM). My goal is to calculate variables within a floodplain area, which I’ve delineated. I originally used Extract by Mask in Arc Toolbox to extract the floodplain area (which is about 0.5 km2), then Focal statistics to calculate the focal mean and standard deviation, which I then used to calculate other variables using Raster Calculator.

I’ve disabled background processing, and have made sure that the coordinate system is the same for the map document, Geoprocessing Environment, and all layers in the map doc. I’ve also set the snap raster to be the mosaic for the watershed for the Geoprocessing environment and every tool. Although each tool yielded output that looked fine, none were aligned with the snap raster. This is problematic when calculating new variables (if they are offset by varying distances and directions) and for extracting values (the variables) to points.

I then created a mosaic dataset and used the clip function to clip the floodplain. The first few times I did this, the results were aligned with the watershed raster, but for some reason, the output from the clip function is now offset by about .5 m to the northeast in relation to the snap raster.

At this point, I can’t get any output using either Arc Toolbox or functions to snap to the raster.

Any suggestions would be greatly appreciated!

Thanks!

Re: Raster output not snapping to raster

DanPatterson_Retired — Sun, 05 Apr 2020 22:35:03 GMT

Snap Raster (Environment setting)—Geoprocessing | Documentation

How the Snap Raster environment setting works—Geoprocessing | Documentation

Trying to figure out what applies to your situation. It is more than coordinate systems, but is affected by cell size and the raster extent.

I hate to you to refer you back to the help topics, but I hope you are setting/checking the snap raster property in the Environments setting for each tool that you use.

If you can narrow it down further with respect to the above comments, that would help

I found no "bugs" that date for 2.5, but older bugs exist on the Support Site, just make sure you sort by Newest to Oldest

https://support.esri.com/en/Search-Results#search?q=%22snap%20raster%22&content-type=Bugs

Re: Raster output not snapping to raster

LauraDeming — Mon, 06 Apr 2020 14:15:45 GMT

Hi,

Thanks for your response. I've reviewed the help documentation a few

times, and I'm pretty sure I am doing what I need to do for the snap raster

work.

1. I've made sure the coordinate system is the same for the dataframe, the

Geoprocessing Environment for the map document, for each layer in my map

document, and for each tool I use.

2. I also check the snap raster for the Geoprocessing Env and for each

tool.

3. I also check the cell size, which is the same for all layers.

I'm wondering if I should reinstall the software, or upgrade to 10.8 if

possible, since every tool I've used in ArcToolbox yields output that does

not align with the snap raster, and the functions used with the mosaic

dataset, which had been working up until recently, are now either not

working at all (no output, and no error message) or the output is not

aligned.

Thanks!

Re: Raster output not snapping to raster

DanPatterson_Retired — Mon, 06 Apr 2020 18:10:25 GMT

Laura, you can attempt a "Repair" from Windows Add/Remove, select Remove, then Repair.

If that does not work I am not even sure upgrading will fix it. Tech Support is still your best option

Re: Raster output not snapping to raster

LauraDeming — Mon, 06 Apr 2020 22:49:24 GMT

Thanks! Hopefully the repair will work!