Topic ID #7155 - posted 3/8/2010 9:29 AM
PennFarms73
Im looking for an online resource that has geo-referenced topos for Pennsylvania and surrounding states. Free would be great, but Im also willing to pay. I need these to load into my handheld GPS mapper. Any help?
where do i find Georeferenced topo maps??
PennFarms73
Im looking for an online resource that has geo-referenced topos for Pennsylvania and surrounding states. Free would be great, but Im also willing to pay. I need these to load into my handheld GPS mapper. Any help?
Post ID#17455 - replied 3/8/2010 2:03 PM
cmarknicholson
Try the NRCS Data Gateway (http://datagateway.nrcs.usda.gov/).
Depending upon the county you're interested in, they may have them available.
Post ID#17458 - replied 3/9/2010 5:12 AM
KB
What kind of GPS do you have?
If you're looking for standard raster DRG's (7.5 min quads) for Pennsylvania, I'd recommend going to the PA Spatial Data Access Site @ http://www.pasda.psu.edu/ and downloading the ones you need.
The NRCS Geospatial Data Gateway @ http://datagateway.nrcs.usda.gov/ is a good place for downloading mosaic'ed DRG's by county for anywhere in the US. The downside to this site is the files are all R-G-B, so they're considerably larger than typical DRG's which have mapped colors.
You can also get DRG's from the USGS Seamless site (seamless.usgs.gov).
For all other states, do a search for <state> GIS clearinghouse and you should be able to find what you need.
If you have a consumer GPS and need vector base maps, there are several free options out there. If this is the case, let me know and I can send you some links.
If you're looking for standard raster DRG's (7.5 min quads) for Pennsylvania, I'd recommend going to the PA Spatial Data Access Site @ http://www.pasda.psu.edu/ and downloading the ones you need.
The NRCS Geospatial Data Gateway @ http://datagateway.nrcs.usda.gov/ is a good place for downloading mosaic'ed DRG's by county for anywhere in the US. The downside to this site is the files are all R-G-B, so they're considerably larger than typical DRG's which have mapped colors.
You can also get DRG's from the USGS Seamless site (seamless.usgs.gov).
For all other states, do a search for <state> GIS clearinghouse and you should be able to find what you need.
If you have a consumer GPS and need vector base maps, there are several free options out there. If this is the case, let me know and I can send you some links.
Post ID#17461 - replied 3/9/2010 7:07 AM
PennFarms73
Thanks for all the helpful links. Im using a Magellan Mobile MApper CX, which is Magellan's move into the world of profesh GPS. overall, its not too bad, but the software, MobileMapper Office, leaves alot to be desired.
I got some geo referenced topos from the PASDA, but when I loaded them into my mapping program, they still had the white borders attached! WEAK!~!
Post ID#17464 - replied 3/9/2010 11:10 AM
KB
I haven't used the PASDA site in awhile -- Many state clearinghouses have "collarless" DRG's available. If you have access to ArcGIS, you can remove them yourself in a few different ways.
If that doesn't work, the NRCS Geospatial Gateway has them by county but you may need to clip them down to a managable size for your GPS (a typical county can range from 100 - 200 MB).
The USGS Seamless site is pretty useful too; you can download seamless DRG's for designated areas.
If that doesn't work, the NRCS Geospatial Gateway has them by county but you may need to clip them down to a managable size for your GPS (a typical county can range from 100 - 200 MB).
The USGS Seamless site is pretty useful too; you can download seamless DRG's for designated areas.
Post ID#17467 - replied 3/9/2010 12:51 PM
PennFarms73
I'll be sure to check out the other sites as well, KB. The PASDA site has been acting sluggish all day, so i was unable to do much. I dont have access or the skills to work in arcgis, so thats out. I think I'll check the seamless usgs site next...
Post ID#17468 - replied 3/9/2010 1:16 PM
PennFarms73
man....why are all these site so difficult to navigate. Google maps needs to offer geo referenced data, then at least it would be user friendly and not so damn clunky.... frazzzled.....
Post ID#17472 - replied 3/10/2010 5:08 AM
KB
It's pretty much like that for every state :-)
Whenever they try to simplify things by adding map viewers and searching software, it just gets exponentially more complicated. I much prefer states that give you a hierarchical tree of what's available and then provide decent documentation & metadata.
Whenever they try to simplify things by adding map viewers and searching software, it just gets exponentially more complicated. I much prefer states that give you a hierarchical tree of what's available and then provide decent documentation & metadata.
Post ID#17485 - replied 3/11/2010 7:23 AM
KB
I just downloaded some collarless DRG's from the PASDA site. The site was acting up but the FTP still worked. To "turn off" the collars, you need to set the symbology for value 13 as transparent. I'm not sure how to do this with the Magellan units but if it's anything like Trimble/Pathfinder Office/TerraSync there should be an option for it.