If Im using a map made in NAD27 do I need to change the datum in Garmin basecamp for it?

If Im using a map made in NAD27 do I need to change the datum in Garmin basecamp for it to be accurate?

  • Depends what you're trying to do, but to be safe I would.

  • Hiking maps and trails. I was thinking about digitizing and georeferencing some of my paper maps. I saw that this can be done on qgis and that the output format should match the map datum. If i set waypoints doing this will I need to convert them before sending them to someone else or does basecamp or my unit automatically convert to WGS84?

  • Waypoints are sent in lat/long regardless of what you set in BaseCamp or on your device and then converted back depending on what is set on the receiving device, you don't need to worry.  

  • I'm not sure what you are trying to do.

    Garmin software and devices always store locations in the WGS84 datum.  GPX files always use the WGS84 datum. 

    If you are hand entering locations in the NAD27 datum, then you will need to setup BaseCamp or you device to the NAD27 datum.  BaseCamp or you device will automatically convert and store in WGS84. 

    If you are importing data into BaseCamp via a file, then the locations must be in WGS84 datum.

    I haven't done much with custom maps, but if that is what you are doing, the coordinates defining the map  (N, S, E, W) will need to be in WGS84,

  • Georeferencing in QGIS can be done in these two ways.  Making ground control points (GCP) using coordinate points on the map and making GCPs with physical features that are visible on WGS84 maps or orthoimages in QGIS.

    If you do the former, QGIS can translate the map to WGS84. If you use physical points, the georeferenced image will be in the CRS of the project.

    If you get NAD27 maps that are already geolocated images, like some from the USGS, then QGIS can translate them to WGS84.