I have used GPS readings and attribute data to create interpolation raster map using IDW method. Usually, GeoTIFF maps have a resolution of 30 m. However, raster map made by me has only 0.0005694 cell size. When I project it using WGS_UTM_45N plane projection system, each polygon (or collection of cells with same value) show much lower area size than they actually are. Help me out plz
I think you created the raster with data in a geographic coordinate reference system (latitude-longitude) so the cell size is in decimal degrees. When you "project" it, are you changing the coordinate reference system/projection in ArcCatalog or via the Define Projection tool? If so, that's just updating the metadata and not the raster's extent/georeferencing. Use the Project Tool instead.
Melita