I am trying to transform precipitation data I got from NOAA from HRAP into Albers Equal Area Conic (USGS). It is an older file (2005) data that is in a point file (grid). Each point represents the total rainfall (inches) for 2005 for that location. Derived using these methods: http://water.weather.gov/precip/about.php. There are no transformations available for HRAP. I even checked the extensive list here to make sure: http://downloads2.esri.com/support/TechArticles/Geographic_Transformations_10.1.pdf
I found this about reprojecting it here: http://www.nws.noaa.gov/oh/hrl/distmodel/hrap.htm
But this requires an XMRG file, which was not sent to me.
I tried your method, but I have a feeling I am defining it improperly. I exported the shapefile to ASCII using "Export Feature Attribute to ASCII" and made it SPACE delimited. I then opened it in Notepad and saved it as a .txt file. Then in Catalog I created the feature class 'From XY Table' and defined the X (Long) and Y (Lat) fields as well as the coordinate system as North Pole Stereographic. I added this into my mxd just to check it out before projecting it to Albers Equal Area (USGS) and let it transform using the 'WGS 84 ITRF00 to NAD 83' transformation on the fly. It came in far north of my other Albers layers that were already in my mxd.
Any idea what I did wrong?
I realize this is a rather old post, but I am working with the daily NWS AHPS Stage III QPE data in shapefile format (pre-March 2017). While I really appreciated your reply (especially helpful in clarifying HRAP meaning), I am still unsure of how to best convert the shapefile points into a raster in ArcGIS based on your reply. I've tried using the "Feature to Raster" GP tool on one shapefile. I get huge grids, something on the order of 33 x 33 km (maybe that's appropriate?).
Focusing on option 3, I'm trying to understand what you mean by "set the cell size against the full range of the AHPS HRAP data set" using the "nws_precip_allpoint_tar" shapefile. How can a vector file have a cell size? Are you just referring to setting the extent of the vector to raster conversion tools in the Environment settings to the allpoint shapefile? Or, is it the cell size taken from the allpoint that's been converted to a raster? If so, do you just use the Feature to Raster Tool and leave the default cell size? Otherwise, re-projection of raster and intersection with vector data seems straightforward. I'm just confused on the best way to convert these shapfiles in a rather obscure projection to a raster useful in analysis. Thanks!!