I am trying to work with the 1 arc second resolution SRTM DEM from USGS's Earth Explorer, with eventual goals of filling its no data areas with an ASTER grid (also of 1 second resolution). I have an idea of how to complete that step; what I am getting stuck on is the way the SRTM DEM loads in ArcMap. When I open the grid and inspect its properties, it shows that the cells' XY dimensions are 0.00055555556 x 0.00027777778. Meanwhile, with the ASTER grids I have, the cell dimensions are 0.00027777778 x 0.00027777778. I have searched extensively for why the SRTM grid's cell size is rectangular but haven't found much. I have tried downloading the grid in all 3 available formats (BIL, GeoTiff, and DTED) but all open the same way.
Is there a way to find this grid so that it has square cells?
Should I consider using another grid altogether?
Are there workarounds for my rectangular cell issue so that the two DEMs I am using can work together?