1. The new Hammond Hill map is a GeoPDF. https://www.dec.ny.gov/lands/8204.html
Most USGS topo maps are available as GeoPDF.
USGS US Topo 7.5-minute map for Dryden, NY 2019 https://prd-tnm.s3.amazonaws.com/StagedProducts/Maps/USTopo/PDF/NY/NY_Dryden_20190925_TM_geo.pdf
You need a program that can use a GeoPDF(r) – a georeferenced PDF file, meaning that it is a Portable Document Format (PDF) file with added information that relates the image to coordinates on a map.The app takes the GPS coordinates from your phone and displays where you are on the GeoPDF map.Avenza seems to be the app that most folks use.Avenza Free limits you to 3 stored maps at a time. So unless you want to do lots of swapping out, most of us pay the yearly price for the Plus version – $29.95 / yr. https://www.avenzamaps.com/
The USGS topo map sources are:
2. Maprika has lots of Geocoded maps – for example Highland Forest. Many downhill ski and other recreation areas.
Maprika uses Geocoded JPEG images for its maps.It is easy to create a Geocoded map – maprika.com/make-a-map.html
It took me less than 15 minutes to do this with the Lindsay-Parsons map in the FLLT Lindsay-Parsons PDF brochure. https://www.fllt.org/preserves/lindsay-parsons-biodiversity-preserve/
3. GPX and KML are track files – used to display a route on a map.
So they are used in a GPS. Or with a GPS app on your smart phone.KML – Keyhole Markup Language is an XML notation for expressing geographic annotation and visualization.
GPX – GPS data file saved in the GPS Exchange format. It contains longitude and latitude location data that may include waypoints, routes, and tracks.
4. If you take photos you can attach them to Google Maps – https://support.google.com/maps/answer/2622947?co=GENIE.Platform%3DDesktop&hl=en Plus I could then use Avenza to put a placemark.
5. One needs to make a distinction between:
a. Apps that display your position on a Geo Referenced map – Avenza, Maprika. b. Stand-alone GPS or GPS apps that are used more for navigation – go to a point; create and follow a track. They display your position on a background/base topo map.Apps like BackCountry Navigator, Garmin Explore, US Topo Maps.
6. More for the mapping geeksVia the help desk for BackCountry Navigator:
MAPC2MAPC is a Windows program (with 3500+ users in 60+ countries) to manipulate digital maps and convert them between different platforms and software.