Need help with a search & rescue ?

[Hillhikerz]

Garmin 60 - When given a square boundary to search or 4 way points to stay inside of; how does one make that happen if possible on a GPS unit. I would like to treat my area like a pong game. Start here move across until the alarm goes off and go up grid and hit the other side alarm goes off and back I go. While it is easy to track where I and the dogs have been, it is proving harder and time consuming to be where we are suppose to be. Hope this makes sense. If my unit can not do that is there another that can. TIA.

[+BlueDeuce]

I don't know your location but given your cacher name I assume terrain is going to be something that has to be managed as well.

[+Walts Hunting]

One way would be to use mapping software to draw four lines connecting the points (making a four sided polygon) then save it to the gpx and tell it to show on the map as a track. Then you could look at the GPS" and stay within the boundaries.

[7rxc]

W.H. is right on with the desireable method, which should be performed at the Operations level and presented to you for use.

 

HOWEVER... that sometimes doesn't happen in real life. We had one similar a year ago, where it was for a thorough sweep of an area based on a missing child behaviour profile. OPs decided on the size of the area, and a central point, and that the axes would be NSEW and that there would be 4 quadrants being searched. They assigned team leaders and we were left to find the method. That was after they decided to mark the axis extents ie. 600m north, and so on. That was fine, but sort of assigned backwards (reverse). It was suggested to them that for future that they pick their spot and then use projection to determine the related waypoints for the markers, which we found could have just as easily been virtual (in the GPS). Anyway those of us who Geocache a bit suggested that it was a better way of starting out the assignment. However, each of us decided that the only way to stay in the space was to do the projections ourself. I cleaned out the one waypoint in the search area ( I had found and logged it already). Cleared up my tracks storage to clean the display. Then I marked the start point (center) with a Green Flag pin marker as and icon. Then projected North 600m and placed a red flag icon. Same for the West 600 m point (I had placed that marker already in reality, before they told us why). A little more projecting and it wasn't hard to create zones to sweep, all marked with flag icons. Yes it is some work, but there it was on my GPS (Map60cx). After that it was gather the searchers (lots of 'convergents') brief them and then do the sweeps. Point is that that will give you a flagged area on your display to keep your track within. And it is not dependent on anything but the GPS. Plus you can adjust it on the fly if you need to narrow or widen. It's not a perfect method, and to be honest there may be better ways, it is just what I did in response to the request we got. I should look at whether something can be done to mark an area, I know that you can place the flags where ever you wish to do so by walking around the perimeter first, we did not because of the pre decided parameters.

 

Certainly led to lots of discussion over the last year though. And a lot of thinking. One thing is that it is limited by HOW it is generated. I did one test using Google Earth paths and areas... still not sure just what was saved there, but on the screen it looked fine, never did try getting it to the GPS though. For plotting on OUR topo maps of this area, there is no useful way to convert from GPS coordinates to the OLD maps. There is a table, but that is no guarantee at all, since there are many variances and not many control samples. i.e. the table says use a 200m (roughly) shift to correct, but two local test spots are 300 and 250 m shifts from that. Another is only 50m offset in the other direction. This was observed carefully, and all I can say is that there can be strong local discrepencies on OLD maps in OUR area. But that is another topic. BTW projections can be done using FizzyCalc on a computer with excellent results.

 

Doug 7rxc

[xyzee]

Make up a route of the 4 corners of the search area, and at the bottom right of that route page select map, and it will show drawn lines around the area. I had to pan the white arrow, from the starting point, over to the black arrow so I could see if it would show my tracks as I moved about, and it does so in the GPS 60 and the 60CSx.

For this property, I started with the SW cor, then SE cor, NE cor, NW cor, and back to the SW cor. All I needed was the L/L for the starting SW cor, as I could then use the projection feature to put in the other corners since I knew the distance and directions. After making the first waypoint, I hit menu and selected Add To Route, starting a new route, and doing the same for each new point

If I get the order messed up, I hit entr and Move, to get the points order correct.

If you leave this map page, to go check on how many of the 10,000 tracks you have used up, you have to start over and reselect the Route Page to get back to the "box".

Thankful that a lot of this can be done in the Demo Mode.

Sometimes the Lat/Lon Grid lines being on can help when using a yellow GPS 60, since it has such a bare Map Page.

[seldom_sn]

One way would be to use mapping software to draw four lines connecting the points (making a four sided polygon) then save it to the gpx and tell it to show on the map as a track. Then you could look at the GPS" and stay within the boundaries.

For mapping software read: MapSource, BaseCamp, Google Earth + GPSBabel. I don't know the mapping programs for other than Garmin products.

 

For GE+GPSBabel save the track as KMZ, unzip it to KML, and use GPSBabel to convert KML to GPX.

[Hillhikerz]

WOW I had a feeling I was in the right place with this post... Yes BlueDeuce the terrain here on the back side of Monterey Bay can get wild & wooly fast... Walt when I first read your post I thought no way, then the light bulb went off and it is no different than watching myself walk around a lake; I just need to create a box and stay inside... I was hoping for a sound solution but this will be an easy quick visual reference to check myself... Real life is why this post is here, are we all on the same datum or page... anyway have some time this weekend to play with this idea doing some field practice... I plan on setting up a few 1/4 mile square tracks and walk them and then see just where I was back on the computer... also being able to create a 4 corner route on the fly and have no 24K map to look at and stay inside the flags... I need a bit more practice... Thanks for all your help, will get back to you... Michael

[+Old Sailor]

Garmin 60 - When given a square boundary to search or 4 way points to stay inside of; how does one make that happen if possible on a GPS unit. I would like to treat my area like a pong game. Start here move across until the alarm goes off and go up grid and hit the other side alarm goes off and back I go. While it is easy to track where I and the dogs have been, it is proving harder and time consuming to be where we are suppose to be. Hope this makes sense. If my unit can not do that is there another that can. TIA.

your talking about either a parallel search or a trackline search pattern......google search and rescue patterns, it shows what you are talking about. If you are given co-ords for start, when to turn, width, next track, etc you can place them in gps and go from there.Thats how we did it on the sar cutters for water searches and our gps's.

[+Chuy!]

Using Walts Hunting's suggestion, I would create the boundary using the Path feature in Google Earth, then complete the path by tracing all the trails and points of interest within the boundary.

 

The Path can be converted into a Garmin track as seldom_sn suggests. I use http://www.gpsvisualizer.com/gpsbabel/ for my conversion needs.

Edited November 23, 2012 by Chuy!