topic Profile graph to use real Z values from TIF raster in 3D Questions

Profile graph to use real Z values from TIF raster

GedMcMahon — Thu, 28 Jul 2022 04:45:14 GMT

I need help using the Profile Graph feature in 3D Analyst (ArcGIS 10.8.1).

I'm trying to generate topographic profiles for a number of sections, using Z values from a TIF raster DEM. I interpolate the line, and then select Profile Graph. The feature works, but it rounds all Z values on the Y-axis to an integer, creating a stepped profile (see attached image).

The TIF raster was generated by a mosaic of smaller LiDAR tiles, using 32-bit FLOAT pixel types.

It seems that the profile graph is only taking the integer values, and ignoring decimal places.

Can anybody help? I need smoother profiles than this.

Re: Profile graph to use real Z values from TIF raster

DanPatterson — Thu, 28 Jul 2022 08:48:57 GMT

Profile graph—ArcGIS Pro | Documentation

Your x-axis suggests that the coordinate system is geographic. Have you selected different units on the graph or used a projected dataset?

Re: Profile graph to use real Z values from TIF raster

GedMcMahon — Thu, 28 Jul 2022 08:55:22 GMT

Yes, the data is geographic, but the x-axis values aren't important to me.
Does this affect the output?

Re: Profile graph to use real Z values from TIF raster

DanPatterson — Thu, 28 Jul 2022 09:13:42 GMT

I would think so give this is mentioned in the help topics. I suspect the apparent rounding may be related to this and a short distance. The values aren't sampled at each cell location on the data source.

Under Distance Units, review or update the units to be used by the elevation profile.

Also, even if the data are 32 bit float doesn't mean that values will have a decimal value other than 0 (eg 10 vs 10.0) So you might want to confirm that the z-values do contain decimal values other than " .0"

Re: Profile graph to use real Z values from TIF raster

GedMcMahon — Mon, 01 Aug 2022 04:03:27 GMT

Thank you very much.

Yes it is working now when I use a projected coordinate system in my Data Frame. It made no difference whether the raster dataset was projected or not.