ArcHydro en HEC-GeoHMS: Het berekenen van basin/river hellingen

Question

<\/HEAD>Ik gebruik ArcHydro en HEC-GeoHMS om een stroomgebied te analyseren, en alles verliep vrij goed totdat ik begon met het berekenen van hellingen. Zowel ArcHydro als HEC-GeoHMS geven mij de foutmelding "The dataset does not have spatial reference. Please specify a valid spatial reference!".<\/SPAN> Al mijn lagen zijn in GCS_WGS_1984, dus ik begrijp niet waarom dit wordt gezegd.<\/SPAN><\/BODY><\/HTML>

ISHAG_ABBASHERABDELKREEM_HASSA · Answer

Hi dear

> R-click on PreFillDEM layer and go to properties > source copy file data source for example (E:\ISHAG\SDI\HY\ArcHydroAnalysis\Raster\Layers\)  and go to open any folder past in track after that you will fine folder of layer into yo will find prj.adf R-click open with notepad (uncheck Always open...) Zunits to  100

Regards

NimiDan-Jumbo · Answer

Please how do you go the prj File to set in meters.

Please I need an urgent assistance with Using HEC GEO HMS.

I have had success running the model, but I'm stock having error message  with the River Slope generation. I am using a USGS DEM. I have also projected the DEM  to a National Grid coordinate system (unit in meters).
The DEM raster I am using works when I calculate basin slope using Arc Hydro but give error message when trying to generate the River slope.

Its say "spatial reference does not have z unit. Assuming Z-unit  is the same as unit linear unit and z factor =1

How can I eliminate this error
Many thanks

PeterWilson · Answer

Hi Michael

ArcHydro and HEC-GeoHMS require that your datasets are stored in a projected coordinate system. The DEM fro CGIAR-CSI are stored in a geographic coordinate system. You need to project the DEM tiles before you can use them to perform any calcs using ArcHydro or HEC-GeoHMS.

Regards