These are supposed to be GeoTIFF files - but I have no experience with this format or what can be done with the proper software. Some info I found on GeoTIFF: http://www.remotesensing.org/geotiff/faq.html
I have GPSTuner right now, but that doesn't seem to support TIFF, let alone GeoTIFF. I've read Fugawi, OziExplorer, and Memory Map support GeoTIFF.
Anyone using any of those programs with GeoTIFF files? Can you just grab your current Long/Lat from your GPS receiver and look that up on your GeoTIFF map and calibrate it that way??
Oh, and do you need the .tfw or .aux files to use the full GeoTIFF features, or (as I understand it), all the metadata is included in the single .tif file? Basically, do I need to download the .tfw and/or .aux files from the USGS site if I want to be able to use all the features of GeoTIFF?
I only know these fliles from the pc side, but that is because I don't use gps on my ax. ( bought a standalone gps unit a long time ago and it hasn't broke yet :ass:) on the pc side, I can load them like any other geocoded data and the will align with my base map information in my GIS software. The ones I am used to are generally aerial maps and are quite large.
Search for a program called global mapper 7 on the net. Its not free but there is a trial. It can convert from each. GeoTIFF has the data embedded, jpeg can't and will have another file. Hope this helps. I used gpstuner for awhilr but found that it doesn't like big maps and was to much work for me.
For the PPC, the software that support GeoTIFF (as far as I know) are OziExplorer, Fugawi, and Memory Map as I noted in my original post.
I'm not looking to convert the USGS GeoTIFF files, so will probably consider using one of the three programs mentioned.
My question is, since the majority of USGS topo maps are GeoTIFF, do I need to download the .tfw file that accompanies each of the .tif file found at http://casil.ucdavis.edu/casil/gis.ca.gov/drg/ in order to have automatic calibration?
After further reading, I am under the impression that those three programs mentioned above should be able to extract the geo data found in the GeoTIFF files and calibrate itself when paired to a GPS. You should not have to pick 3 points on the map and input the Long/Lat like you would for non-GeoTIFF map files right (jpeg, bmp) ?
While not an expert on GeoTIFF files I believe that the tif file is just an image, and all the registration information (scale, lat and long) are in the accompanying file. So I believe you will need both files for automatic registration of the image with programs that support these formats. Most of my experience with these files has been with Land Development Desktop though, not with PPC programs.
My question is, since the majority of USGS topo maps are GeoTIFF, do I need to download the .tfw file that accompanies each of the .tif file found at http://casil.ucdavis.edu/casil/gis.ca.gov/drg/ in order to have automatic calibration?
No you don't need it. I use them all the time without the tfw file. There maybe programs that need them but I have not found one yet.
Thanks for confirming that. So you're able to load up these GeoTIFF files and the program you use automatically calibrates and is able to plot your present location on the maps without the need for a 3-point calibration?
From what I've read, it seems the GeoTIFF files have all the info needed for automatic calibration as long as the software opening up the file supports it (it's an open standard, so should not cost the software companies any money to provide that support). The .tfw files are TIF World files that contain the Long/Lat info for that specific map - but it's only limited info. The TIF World file only embeds the UTM coordinates of the first pixel in the upper left corner of the map, but doesn't tell what the geodetic datum or UTM zone of the map is, which is needed for a complete calibration.
I've read that many of the untrimmed USGS maps contain this info in the index/legend of the maps. You can then put this info into your program and it should calibrate (this is for non-GeoTIFF files).
Would like to hear other's experiences with Fugawi, OziExplorer, or Memory Map, and USGS GeoTIFF topo maps.
No problem. I presonally use Memory-Map for almost all my hiking trips. I purchase it with MM maps for ease of use and to have elev data for elev profiles. I could have D/L the maps from a GIS site for free then bought MM elev for a lot less. What I mostly like about MMNav: its PC and PDA software that work togeather pretty well, using my only own scanned maps,and the small footprint it creates its files into. A 20meg scanned tiff, turns into a 3-4meg file on the pda. Also when I've calibrated my maps, it stored the info into the tiff and not another file. Cailbrate it once, and it should work for other problems without calibrating it.
Solara - Your link in your first post is best resource for info about geoTIFF files. These images contain geographic data in the header of the file. The geographic data in the file is used to position (georeference) the image with respect to real world coordinates (e.g. for use with GPS & GIS). The *.tfw (TIFF World Files) files are often included with image downloads because some image display programs are not capable of reading the embedded geo data, and these do contain the same header data that is included in the geoTIFF.
As for OziExplorer, I had played around with the program a couple years back and recall that it used it own image format. The desktop version included tools to convert several image formats.
You can use this free tool to examine and edit the geo referencing data in a geoTIFF.
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bought a standalone gps unit a long time ago and it hasn't broke yet :ass:) on the pc side, I can load them like any other geocoded data and the will align with my base map information in my GIS software. The ones I am used to are generally aerial maps and are quite large.
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