I have rasters, need to be geo-referenced in WGS 84 datum with Lat/Log (degree). I have geo-referenced using Global Mapper, which we usually used to use, because of its user friendly. Got a vector data of the same raster through other sources, which also used GCS_WGS 84 (Could have been geo-referenced using ArcGIS with GCS_WGS84). When I overlap both the data, found off-set about 300 meters. Checked all data origins and geo-referencing, everything correct, still off-set unavoidable.
To check further, I have geo-referenced same raster with GCS_WGS84 in Global Mapper and ArcGIS seperately. I found the same off-set of 300m.
Is that really different transformation applied in difference platforms, or any other parameters related to this??
ArcGIS for Desktop with geographic/datum transformations is a late-binding system. We do not link a default transformation to a particular geographic coordinate system. When data needs to be transformed, then you set the transformation that you want used.
It's possible that Global Mapper is an early-binding system that sets a default transformation per geographic coordinate system.
Because of the size of the offset, I think no transformation occurred in ArcGIS.
Using Global Mapper, I created a simple shapefile having 9 adjacent shapes laid out in a rectangle. I used this layer to clip aerial imagery to the boundaries of each feature in the shapefile using Global mapper. the clipped shapes are exactly coincident with the polygon edges.
When I import both the shapefile and cllipped images into ArcMap V10.2, the shapes and imagery become offset approximately 1.5 meters. Also, The latlong of a known point in the polygon/imagery overlap in ArcMap is hundreds of meters offset from the lat/long of the same point in Global mapper.
Also when I load the data in QGIS the layers are all conincident, only when I load into Arc10 are they not coincident.
In global Mapper the projections are:
shapefile: WGS84 - lambert Conformal -Washington State Plane South -feet (US Survey) Imagery: WGS84 - Geographic ( lat/long) - Arc Degrees EPSG Code 4326 (obviously not Wash State Plane-South)
Problem 1: How do I correct this overlap to achieve coincident data in ArcMap?
Problem 2: In Arcmap I went into Catalog image file/properties and changed the image projection to State Plane South - the image file then disappeared from the screen and would not display. reset the original projection and it re appeared.