Hi all, I need a little help determining the possible coordinate system for a set of 1930s topographic maps of the Shanghai area. The maps were drawn by the Japanese for parts of China. Date for this particular set is 1932 - 1937, scale 1:25,000.
What we are doing is creating index grids for these map sets (see here for other sets already online), the index is hosted online and links the user back to the digital scan and metadata record on the library site. Most of these maps have both scale and corner coordinates indicated making a fishnet easy to create in ArcGIS to replicate the index. These maps of China however have no indication of coordinates or projection that I can find.
The substitute approach has been to georeference one map scan and build the index off that, but despite getting a good match for the scan, the index's quickly get out of alignment with the scans, so clicking on an edge box in the index gives you a scan that may not fully match what the index map online shows.
I think this may be partly due to the fact that we can't determine a best match for a modern projection in ArcGIS to use with these older maps.
I know there are some users here with VERY good projection sleuthing skills, hoping I can get one of you to take a look at this map and see if you can guess it's projection?