Q:

Using Polyline to Raster tool in ArcGIS

Pretty basic question; In this Polyline to Raster tool, there is a field called "Value Field"
I am not sure what to put for this field. My polylines are ZM, so there is Z information for the line, I figured this tool would use that information to build the raster. How can I get the value field to you this z information??

A:

You can find the Z values of the watercourses at your sample points without raster:

Using the tool Split line at Points you can break the lines (to
an output feature class), if you have Z values the value at the
point of intersection is interpolated. Use a small tolerance or the
lines will not be broken, for example if your projection is metres a
value of 2.5 cm would be fine.. it just depends on how well your
points are snapped.
Convert the split lines to points using Feature Vertices to
Points (advanced license required) with the BOTH_ENDS option as
we're only going to be interested in the ends.
Add XY coordinates to the end points so the values are
tabulated. As the input points have Z values a Z field will be added
and populated with the Z values of the end points.
With Near (advanced license required) or Spatial Join
correlate the sample points with the endpoints (use a small
tolerance).
Attribute join your sample points to your near/spatial join
table to find the Z value at each sample point.

If you do want a raster then create a terrain, add your watercourse lines to it, build and then export to raster - 3d Analyst license required.

