topic HEC-geoHMS longest flowpath error in Water Resources Questions https://community.esri.com/t5/water-resources-questions/hec-geohms-longest-flowpath-error/m-p/426625#M2104 <HTML><HEAD></HEAD><BODY><P>I've tried this with several different projects and it keeps giving me an error at his step (after processing for about 55 min). See attached error message.&nbsp;</P></BODY></HTML> Wed, 05 Feb 2020 15:09:35 GMT Anonymous User 2020-02-05T15:09:35Z HEC-geoHMS longest flowpath error https://community.esri.com/t5/water-resources-questions/hec-geohms-longest-flowpath-error/m-p/426625#M2104 <HTML><HEAD></HEAD><BODY><P>I've tried this with several different projects and it keeps giving me an error at his step (after processing for about 55 min). See attached error message.&nbsp;</P></BODY></HTML> Wed, 05 Feb 2020 15:09:35 GMT https://community.esri.com/t5/water-resources-questions/hec-geohms-longest-flowpath-error/m-p/426625#M2104 Anonymous User 2020-02-05T15:09:35Z Re: HEC-geoHMS longest flowpath error https://community.esri.com/t5/water-resources-questions/hec-geohms-longest-flowpath-error/m-p/426626#M2105 <HTML><HEAD></HEAD><BODY><P>Jack,</P><P>You may want to check out the thread <A href="https://community.esri.com/thread/43771">ArcHydro Problem Solvers</A>&nbsp;and see if there is an answer there.</P><P></P><P>I'm not familiar with this particular error. The error message seems to point to the grid, though in the geoprocessing, the tool may convert vector data to a grid, so I can't say for sure if it is the grid you input, or a temporary grid.</P><P></P><P>The inputs to the LongestFlowPath tool are a Drainage Area (polygon) and Flow Direction Grid (grid).</P><P><IMG __jive_id="480345" class="image-1 jive-image" src="https://community.esri.com/legacyfs/online/480345_pastedImage_3.png" /></P><P>Check your inputs to make sure they are correct.</P><P>Check your inputs to make sure they are in the right projection.</P><P>Check you processing extents to make sure they cover the processing area.</P><P></P><P>Best,</P><P></P><P>Mark</P></BODY></HTML> Wed, 05 Feb 2020 16:32:19 GMT https://community.esri.com/t5/water-resources-questions/hec-geohms-longest-flowpath-error/m-p/426626#M2105 MarkBoucher 2020-02-05T16:32:19Z