I'm creating shapefiles of Malaysian Expressway in ArcGIS pro, which Basemap is precise and reliable should I use; Imagery or Open Street Map? Because I note that they are not identical to each other and my work needs precisely to simulate the real-world road features. Thanks
For road related GIS works, I think open street map is the best option. However, imagery has some advantages since it is widely used. I think depending on your use , you can decide on this. You can see the documentation of ArcGIS on basemaps. It can give you an idea regarding the choosing process.
Good day,
The advantage in using osm is that you can download the database online, it is composed of shapefiles (landuse, road, railways.. etc) then you can use the clip tool in arcgis to get the desired information in your study area.
Why would you trust either?
Apply the basic principles of GIS quality ( 6 Elements of Data Quality - Positional Accuracy, Thematic Accuracy, Completeness, Logical Consistency, Temporal Quality, Usability ) https://pro.arcgis.com/en/pro-app/latest/help/data/validating-data/identify-data-quality-requirements.htm
Really, do you know the original source of the OSM data ( https://blog.openstreetmap.org/2018/03/18/1-million-map-contributors/ ) - some of it really, really good, and some of it is garbage, including fictitious features added by random Pokemon Go players ( https://www.youtube.com/watch?v=DHj8pH5V1GA ). Maybe just check that mostly non-existent version history.
By the same token, depending on where in the world you are at and which ESRI data source you are using, the Imagery layer may a fitness for use as a 'backround' layer, and it's external positional accuracy suspect, and it's internal positional accuracy suspect because of barely passable ortho-rectification ( this is really problematic in urban areas and especially traffic right of ways with viaducts and bridges - and again, ESRI uses other people's data, so can you find meta-data for the specific scene you are using? And will it change the next time you open it or switch zoom levels because it was updated or they changed suppliers?
Did you attempt to obtain data ( engineering drawings, project aerial imagery, and especially survey points of various types: http://www.mygeoportal.gov.my/taxonomy/term/167 ) from your local government sources? Often times they will make these available for academics even if they are not publicly posted. The latter points can be used to validate and correct other marginal sources like OSM and background imagery from generic services like ESRI.
I think open street map is the best choice, but this depends on your work goals
In any way imagery is always much more precise, reliable and context-rich basemap. In some cases maps like OSM could be more useful, though.
Please, use OSM as base map and also use the imagery to verify the map and make it more reliable.
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