Broad Creek Memorial Scout Reservation

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This Wiki is for all mappers contributing to mapping Broad Creek Memorial Scout Reservation, Harford County, MD, and operated by the Baltimore Area Council.

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Broad Creek Memorial Scout Reservation, Harford County, Maryland
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latitude: 39.69, longitude: -76.27
Browse map of Broad Creek Memorial Scout Reservation 39°41′24.00″ N, 76°16′12.00″ W
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Broad Creek Memorial Scout Reservation is a Scouts BSA Campground in Harford County, Maryland at latitude 39°41′24.00″ North, longitude 76°16′12.00″ West.

Imagery and Alignment

The best imagery set to use are the MD Latest 6 Inch Aerial Imagery set and the MD Harford County and immediate surroundings LIDAR imagery.

MD Latest 6 Inch Aerial Imagery

To add this imagery set to the JOSM editor:

  1. Select the Edit -> Preferences menu.
  2. Click on the Imagery tab.
  3. In the Imagery Providers tab in the Available default entries table, scroll down to the MD Latest 6 Inch Aerial Imagery entry under the Menu Name (default) column for the US country code and select it.
  4. Under this table, select the Activate button.
  5. Click OK
  6. A dialog appears stating JOSM will need to be restart for this change to take effect. Save any unsaved work and restart.
  7. The MD Latest 6 Inch Aerial Imagery should now be available under the Imagery menu.

To properly align the MD Latest 6 Inch Aerial Imagery to it's actual location:

  1. Select the Imagery -> Imagery Offset menu item.
  2. Select the New Offset submenu (you may have to first select the MD Latest 6 Inch Aerial Imagery submenu first if more then one imagery set is currently loaded in JOSM.
  3. In the Adjust imagery offset dialog, enter "-0.57; 0.50" in the Offset entry. Go ahead and set a bookmark name ("MD 6 Inch using Trimble DA1 Geolocation" is suggested).

This imagery offset was determined using a ground survey with a Trimble DA1 antenna with 1-meter correction. The survey points used are the firepits at the Saffron Jamestown, Susquehanna, and Long Range campsites. The currently mapped firepits should hit pretty much in the center of the firepits seen in the imager. So aligned, the firepit outside the Pioneer Cabin should similarly align to the mapped firepit and that seen in the imager. The mail Saffron flagpoles should also be aligned (at the base of the flagpole on ground level - not the top).

MD Harford County and immediate surroundings LIDAR

Maryland make LIDAR scans freely available. Using LIDAR, a mapper gets a look under tree and other vegetation cover reveal many features not otherwise visible. This includes constructed (e.g. cut into hillsides) or eroded trails, tracks, roads, quarries, mines, streams, rivers, lakes (and their banks) and more. Couple with the MD 6 Inch imagery, a very accurate map can be created (assuming everyone sticks with the same alignment).

The Maryland LIDAR imagery is provided through the MD iMap Portal. To view the LIDAR imagery, scroll down to the LIDAR and Derived Products link and select to bring up the LIDAR Overview page. Scroll down again and select the Topography Viewer link to bring up the LIDAR map. Your can brown this map much the same way as using Google or Bing maps on the web. Controls in the right margin allow selecting between Shaded Relief, Slope, Aspect, and Hillshade views for the entire state or individual counties. The Shaded Relief map is perhaps the most useful - instructions for making this view available in JOSM are provided below. Note that within these controls the MD 6 Inch imagery is also available.

The easiest way is to edit your preferences XML file directly:

  1. Close JOSM.
  2. Navigate to the C:\Users\<account>\AppData\Roaming\JOSM folder using the File explorer or the command line in your favorite shell.
  3. Make a backup copy of the preferences.xml file.
  4. Edit the preferences.xml file in your favorite editor.
  5. Scroll down to the <maps key='imagery.entries'> section.
  6. Insert the following XML code into this XML section below the <maps key='imagery.entries'> and before the </maps> line. DO NOT insert within any other <map> ... </map> section. (There should be no line breaks or spaces in the "value=https://lidar.geodata.md.gov/...;BBOX={bbox}'/>" text below.
  7. Save the file and start JOSM. MD Harford County and immediate surroundings LIDAR should now appear in the imagery menu.
    <map>
       <tag key='projections' value='EPSG:4326,EPSG:26985,CRS:84'/>
       <tag key='transparent' value='true'/>
       <tag key='minimumTileExpire' value='3600'/>
       <tag key='name' value='MD Harford County and immediate surroundings LIDAR'/>
       <tag key='type' value='wms'/>
       <tag key='url' value='https://lidar.geodata.md.gov/imap/services/Harford/MD_harford_shadedRelief_RGB/ImageServer/WMSServer?FORMAT=image/png&amp;TRANSPARENT=TRUE&amp;VERSION=1.3.0&amp;SERVICE=WMS&amp;REQUEST=GetMap&amp;LAYERS=0&amp;STYLES=&amp;CRS={proj}&amp;WIDTH={width}&amp;HEIGHT={height}&amp;BBOX={bbox}'/>
      <tag key='cookies' value=''/>
      <tag key='customHttpHeaders' value='{}'/>
    </map>

To properly align the MD Harford County and immediate surroundings LIDAR to it's actual location:

  1. Select the Imagery -> Imagery Offset menu item.
  2. Select the New Offset submenu (you may have to first select the MD Harford County and immediate surroundings LIDAR submenu first if more then one imagery set is currently loaded in JOSM.
  3. In the Adjust imagery offset dialog, enter "0.33; -0.76" in the Offset entry. Go ahead and set a bookmark name ("Harford County LIDAR" is suggested).

This imagery offset was determined by first aligning the MD 6 Inch imagery, mapping some roads, and then aligning the LIDAR to intersections of the mapped roads.

Please Do's and Do Nots

  • Please DO use your GPS when mapping trails but please DO NOT make changes to existing trails based on one GPS trace. Consumer GPS units are only accurate down to several meters and are affected by tree cover (generally winter traces should be more accurate than summer). Several GPS traces are required to average out the error of any one trace.
  • Please DO use a precision GPS with error correction such as the Trimble DA1 with at least the 60 centimeter correction subscription.
  • Please DO defer to using LIDAR if the feature you are mapping is visible in LIDAR. In such cases the GPS trace is useful in correlating the feature you are mapping to the LIDAR imagery.
  • Please DO NOT set any features on Broad Creek to access=private or access=permissive (or foot=private and similar). Setting access=private defeats the auto-routing feature in GPS units and applications such as Garmin Base Camp. This obviously prevents Broad Creek campers being able to plan out routes using their GPS defeating our hard earned efforts in mapping Broad Creek. Setting access=permissive can change the appearance of trails as map makers prioritize access over the type of trail or road (e.g. the JOSM editor is a good example rendering all highways (trails, tracks, roads) using the same breadcrumbs). Poachers and hikers who ignore No Trespassing signs don't care about OSM tags. See Tag:access=private for more information.

Broad Creek Mapping Status (month/year)

  • Broad Creek boundaries have been mapped using coordinates available from Harford County. (3/22)
  • All camp sites and cabins have been mapped. The area for each camp was mostly arbitrary based on local knowledge as there are no distinct boundaries. For Camp Saffron, the camp sites boundaries we drawn to include the semi-permanent tent platforms. (3/22)
  • Major water features have been mapped with both the MD 6 Inch and LIDAR imagery and should not need adjusting. Note Lake Strauss and Broad Creek shorelines have been mapped to banks visible in LIDAR data - not to whatever the water level was when the MD 6 Inch imagery was taken. (3/22)
  • Minor water features have been mapped mostly using LIDAR data as have gulleys (Tag:natural=gully). (3/22)
  • Some springs have been mapped but there are more to be done. (3/22)
  • Several of the new water spigots and electrical transformers along with flag poles have been mapped in Saffron using 1-meter accuracy from a ground survey using a Trimble DA1. (3/22)
  • Most trails have been mapped but the accuracy varies considerably. Since most of the Broad Creek trails were not constructed (e.g. treads cut into the sides of hills) and do not have a lot of erosion they are often not visible in LIDAR. Trails that follow old farm and quarry roads are usually visible. (3/22)
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