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The original Slope raster was in degrees, however it is converted to radians in the equation. I originally divided by 100 so may stick with that.
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05-24-2016
03:05 AM
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Hi, i'm using the follow equation to create an LS factor for RUSLE, if anyone has used a similar equation did they divide the output by 10 or 100? LS = Power(FlowAccumulation * 50 / 22.1, 0.4) * Power(Sin(Slope * 0.01745) / 0.09, 1.4) * 1.4 It has been used in studies [1,2] and my results seem more accurate when dividing by 10. Thanks. [1] Prasannakumar, V., Vijith, H., Abinod, S., Geetha, N. 2012. Estimation of soil erosion risk within a small mountainous sub-watershed in Kerala, India using Revised Universal Soil Loss Equation (RUSLE) and geo-information technology. Geoscience Frontiers, 3(2), pp. 209-215. [2] Parveen, R., Kumar, U. 2012. Integrated Approach of Universal Soil Loss Equation (USLE) and Geographical Information System (GIS) for Soil Loss Risk Assessment in Upper South Koel Basin, Jharkhand. Journal of Geographic Information System. 4, pp. 588-596.
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05-24-2016
02:30 AM
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Re-done the analysis in British National Grid (OSGB 1936), seems to have worked. Thanks.
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05-23-2016
07:45 AM
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Hi, i have a raster in which the values represent soil loss (t h-1 y-1) would like to find the area of each class in hectares, but i am unsure of the calculation. I have reclassified them with the same classes. The raster properties are as follows: Attribute table: The units are in meters (OSGB 1936). using this cell size does 1 pixel therefore represent 0.00029 hectares in this case? (1 sq m = 0.0001 hectares). So 556,236 x 0.00029 = 161.3 hecatres sq - does that seem correct? Thanks
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05-23-2016
06:11 AM
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Note: I have been clipping (Data Management > Clip) the GRS_1980 data to the OSGB data prior to attempting any transfomations.
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05-12-2016
02:30 AM
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OSGB data is here: I've already succesfully used the OSGB to ETRS_1989 transformation on this data:
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05-12-2016
02:09 AM
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This is the original data: Following what you said Neil I changed the GCS to WGS 84 through this dialog: Then I used Project Raster > OSGB to WGS84: However i'm still getting this error: Thanks for the help
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05-11-2016
01:57 PM
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Hi, I changed the Geographic Coordinate System to ETRS 1989 using this dialog, however i'm still getting the same error when I use Project Raster.
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05-11-2016
02:47 AM
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Sorry i'm not following there, what should I do differently? Thanks
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05-08-2016
01:43 PM
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Hi thanks for the reply, I redfined the raster to ETRS 1989 (Data Management > Define Projection), I then tried Project Raster using the following: Output coordinate system: OSGB 1936 Geographic transformation: OSGB_1936_To_ETRS_1989_1 However i get the error "ERROR 999999: Error executing function. General function failure [Rf_ProjectRaster] The operation was attempted on an empty geometry. Failed to execute (ProjectRaster)." Im using ArcMap 10.3.1, the raster also dissappears once i've defined the projection as ETRS 1989. Just to clarify the raster Spatial Reference is defined as GRS_1980_IUGG_1980_Lambert_Azimuthal_Equal_Area. Thanks.
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05-06-2016
03:12 AM
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The OSGB spheroid is Airy 1980 (EPSG 7001), not sure of the spheroid for the GRS_1980. The pdf doesnt contain mentions of spheroids used in the transformations either.
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05-04-2016
08:29 AM
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Can't seem to find any mention of a GRS_1980_IUGG to OGSB_1936 transformation in the .pdf.
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05-04-2016
06:48 AM
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Hi Dan, I wasn't using that tool initially, I attempted it through the 'Geographic Coordinate Systems Warning' that opened when i added the layer. I will try what you suggested. Thanks
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05-04-2016
06:10 AM
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