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1

I discovered my error. I was expecting to see lat/lng pairs from EPSG:3857, but it's actually EPSG:4326 I should have been converting to.


0

I learned that ArcGIS has a georeferencing feature called autoregistration that performs this task with some caveats. They say it does not work well in my use case of old scanned maps. QGIS has no similar feature, so I wrote a script in Python using the OpenCV library that looks for general image similarity, maps the correspondence, and then transfers ...


1

Changed .upper == to .upper() == and it works.


1

Try something like this: import sys, arcpy, os mypath = "C:\input" Images = [] arcpy.env.workspace = mypath for ThisFile in os.listdir(mypath): thisName,thisExt = os.path.splitext(ThisFile) if thisExt.upper() == ".TIF": Images.append(ThisFile) out_workspace = r"C:\Users\Robby\Desktop\Test" OutSR = arcpy.SpatialReference(26916) # ...


1

Maybe you don't have to redigitize your points. Once you are able to reference your png you can also transform the points you digitized so far. First you have to check, which projection your png file resembles. Depending on the projection that had been used to produce your png ireland could look quite differently. Next thing you need are at least two pairs ...


3

Because the comments seem to have constituted a satisfactory answer, I am copying them here for the record (and adding a few edits to improve them). How could the values not change? Consider what happens during the reprojection. Because the raster is truly being warped, each cell in the new version has to reflect some combination of values from the ...


4

You can do this using a Postgres DO block, essentially an anonymous function that you just run once from a psql prompt. Something along these lines: DO $$declare r record; BEGIN FOR r in SELECT srid as srs, f_table_name as name, f_geometry_column as geom FROM geometry_columns WHERE f_table_schema = 'schema_name' LOOP RAISE NOTICE ...


1

Start a new, blank map or in your current map go to step 2. Double-click or right-click > properties on the dataframe (named Layers by default) in the Table of Contents (ToC). Go to the Coordinate System Tab, drill down through folder tree to Projected Coordinate Systems > UTM > Europe > European Datum 1950 UTM Zone 31N and highlight it, then click Ok. ...


0

When you add a layer to Arcmap, If this is the first layer, Arcmap will automatically set the coordinate system of data frame to that of the layer. When you add a second layer in a different coordinate system, Arcmap tries to project that layer (here WMS), to the projection system of the data frame (If there is a valid transformation between them). Now, ...


1

The scale option is only needed for "unprojected" rasters with units in degrees. It is the ratio of height units used in the DEM (typically meters) to distance units in degrees. So for Mercator or other projected rasters, you can ignore the scale option, or use the default of 1 (no scale).


2

The part that is going wrong is where you assumed that the coordinates in 3857 are degrees (like -5.8, 41). The units of 3857 are metres. So you're asking for something tiny, off the map (near the origin). Lets look at a conversion, using pyproj: from pyproj import Proj, transform inProj = Proj(init='epsg:4326') outProj = Proj(init='epsg:3857') x1,y1 = ...


0

Now that I have significantly more R experience under my belt, it's time to answer this question... First was to make sure the geocoded address was converted to a spatialpoint cleaner: AddressDetail <- geocode(match_address) coordinates(AddressDetail) <- ~lon + lat Then the relevant projection was assigned to the spatialpoint wgs84 <- ...



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