Hi Tariq:

If you want to use open source software GDAL is your option. GDAL_TRANSLATE tool ollows you the work (http://www.gdal.org/gdal_translate.html)

To convert geotiff to ASC or AAIGrid format you can use

gdal_translate -of AAIGrid elevation.tif elevation.asc

gdal_translate -of XYZ elevation.tif elevation.xyz

I hope it helps you

Yes factually as the previous answer you could use the export and import tool in ERDAS or if you have not ERDAS you could yous the same tools under ENVI.

I think it is very simple in ArcGIS and using of Conversion tools.

Best

Hi Tariq:

If you want to use open source software GDAL is your option. GDAL_TRANSLATE tool ollows you the work (http://www.gdal.org/gdal_translate.html)

To convert geotiff to ASC or AAIGrid format you can use

gdal_translate -of AAIGrid elevation.tif elevation.asc

gdal_translate -of XYZ elevation.tif elevation.xyz

I hope it helps you

If you are familiar with R, you can use the functions of the R "Raster" package (what uses gdal on the background) .  "WriteRaster" function will work to save to a geotiff or grid format. You can also use the R package "gdalUtils" who invoque gdal_translate or other gdal tools

Gdal is going to handle almost all kinds of raster formats, while R-raster package only support few.

We can use both the ERDAS and ArcGIS (in ArcGIS only TIFF option only available) for the same purposes. In both the softwares, we have import / export options. In ArcGIS, if the data (raster) is added in the viewer you can just right click in the  raster choose DATA option and export data to make the tiff file and wise verse.

Hello

You can use GIS by using direct expot option.

In ArcGIS 10.2:

Toolbox/conversion tools/to raster/Raster to other format (multiple)

Inside the tool you can select the output format (tiff, grid, etc.)