DTM editing

[PeterMichalak]

Dear,

I'm having problems editing my DTM (Tiff format). I need to assign a certain elevation for a river. Is it possible to draw a polygon covering the river, with a certain elevation value and somehow merge it with the DTM raster? Or is there an easier way to cope with it?

Thanks for your help

Peter

[PeterMichalak]

Right,

I have managed to sort the problem out, if anyone has the same issue I'd suggest the following:

1) Draw a shp representing river > Convert shp to Raster with a predefined value of 87 (elevation)

2) Cut the DTM raster using Mask tool in Image Analysis Window

3) Clip 2 rasters using Mosaic to New Raster Tool

4) I've used SetNull tool to Set Null values for the background

Everyting worked fine except I've got small gaps where there 2 rasters meet (after using Mosaic to New Raster):

I'm not sure what have caused this, probably the fact that rasters were cut using polygon which represents irregular shp, comparing to raster's regular cell grid. Anyway I'm not sure how to get rid of these gaps, I have tried Snap to Raster setting but did not help.

Any suggestions?

Regards,

Peter

[JimHall]

The problem may be in your not setting the "snap raster" for your outputs.  Set environment setting to your original raster for all your steps.