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SDE to KML Issue

  • 16 June 2018
  • 5 replies
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dmerrick
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Hi,

I am having an issue converting data from an ESRI SDE connection to KML file in FME due to 1.3m shift from the same conversion in ArcMap.

My SDE data is NAD 83, UTM Zone 10N (WKID: 26910). I have no issues connecting to the SDE, I get the same 1.3m shift using a Writer or a FeatureWriter. I do get a warning of:

NOT changing coordinate system of reader identified by keyword `GEODATABASE_SDE_1' from `EPSG:26910' to `_UTM83-10_0' -- mapping file setting of `EPSG:26910' overrides coordinate system `_UTM83-10_0' read from file

If I put the SDE coordinate system of "UTM83-10", I still get the same error.

 

Once exported, regardless of which coordinate system i use, the 1.3m shift is still present in the kml. I have exported from the SDE into both a file geodatabase and shapefiles and repeated the same process and I get the same results.

 

If I re-import the KML into FME to a shapefile and compare to the original in ArcMap, there is no shift.

 

If I import the same kml directly in ArcMap the shift is still present.

 

I have tried playing with the EsriReprojector tool in FME (and the standard Reprojector) but I have been unable to solve the issue.

I know I have a 1.3m shift due to the ESRI "Layer to KML" tool to produce the same KML data. I need to be able to convert the data in FME due to the 40+ datasets I am converting on a regular basis to various formats.

Thanks!

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Best answer by dmerrick 20 June 2018, 01:16

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daveatsafe
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Hi, @dmerrick,

The difference is likely due to the datum transformation between NAD83 and WGS84.

FME's Reprojector and CsmapReprojector have a default null datum shift between NAD83 and WGS84, effectively treating them as equivalent.

The EsriReprojector offers a number of datum transformations between GCS_WGS_1984 (which is what KML data is stored in) and NAD_1983_UTM_Zone_10N.

Unless these transformations are null, they will produce a different location than the Reprojector, or the automatic reprojection done by the KML writer.

For the best results, I would recommend using the EsriReprojector with the same datum transformation used during the Layer to KML conversion.

Alternatively, we could create a transformation for the CsmapReprojector to match the Esri transformation, then reproject to LL84 with CsmapReprojector before writing to KML.

dmerrick
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Thanks @DaveAtSafe, I was unable to solve the 1.3m difference with the datum transformations in FME. ESRI 10.5 (and 10.3) uses a Geographic Transformation of "NAD_1927_To_NAD_1983_NADCON" when it converts the parcels, I have been unable to determine why, and ESRI does not allow a different Geograhic Transformer for that tool; either from the ArcToolbox or from a Python Script (same for batch processing). I have included a zipped folder containing a small subset of parcels, the ESRI KMZ and the FME KMZ. Your help solving this problem would be greatly appreciated

parcels.zip

daveatsafe
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Hi @dmerrick,

Please use the EsriReprojector in your FME workspace to reproject the data from NAD_1983_UTM_Zone_10N to GCS_WGS_1984, using the transformation NAD_1983_To_WGS_1984_1.

This will give results within less than a millimeter from the ArcGIS KMZ output.

dmerrick
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@DaveAtSafe, thanks for the reply. I found your solution did not solve the 1.3m shift I was experiencing. The FME inspector showed that the parcels (SDE, Shapefile, FME KML) all lined up, but not the ESRI KMLs.

 

After going over the ESRI Layer to conversion tool (http://pro.arcgis.com/en/pro-app/tool-reference/conversion/layer-to-kml.htm) help document

 

 

I "Projected" the data in ArcMap to WGS_1984_ARC_System_Zone_10, which uses the Geographic Transformation "WGS_1984_(ITRF00)_To_NAD_1983", and then "Layer to KML".

 

This produced the same results as before in ESRI for the parcels.

 

Using the EsriReprojection Transformer in FME with the same settings before the KML FeatureWriter now produces the same results

 

Problem solved!
dmerrick
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Hi @dmerrick,

Please use the EsriReprojector in your FME workspace to reproject the data from NAD_1983_UTM_Zone_10N to GCS_WGS_1984, using the transformation NAD_1983_To_WGS_1984_1.

This will give results within less than a millimeter from the ArcGIS KMZ output.

@DaveAtSafe, thanks for the reply. I found your solution did not solve the 1.3m shift I was experiencing. The FME inspector showed that the parcels (SDE, Shapefile, FME KML) all lined up, but not the ESRI KMLs.

 

After going over the ESRI Layer to conversion tool (http://pro.arcgis.com/en/pro-app/tool-reference/conversion/layer-to-kml.htm) help document

 

 

I "Projected" the data in ArcMap to WGS_1984_ARC_System_Zone_10, which uses the Geographic Transformation "WGS_1984_(ITRF00)_To_NAD_1983", and then "Layer to KML".

 

This produced the same results as before in ESRI for the parcels.

 

Using the EsriReprojection Transformer in FME with the same settings before the KML FeatureWriter now produces the same results

 

Problem solved!

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