hmueller@wfsc4.tamu.edu (Hal Mueller) (03/22/90)
I've followed up on some of the information that was posted recently regarding digital maps. Here's what I've learned from ESIC (nee NCIC): There are two types of products available, DEM (digital elevation model) and DLG (digital line graph). DEM files are raster based elevations. DLG files are vector based representation of hydrology, transportation, political boundaries, and sometimes other information. DEM is available from EROS Data Center at 1:250 000 scale for the entire US. DLG is available from them at 1:2 000 000 scale for the entire US. For some areas of the country finer resolution data is available. DLG exists at 1:100 000 scale. DLG and DEM exist at 1:24 000 scale (a 7.5' quad map). ORDERING: The coarse DEM/DLG data (250K and 2000K) is a complete data set. It is handled by EROS data center. Price is $40 for 1 file, sliding higher for 2-4 files; for 5 or more files prices is $90 plus $7/file. A file is 1 layer (hydro, trans, boundaries) for 1 section of the country. There are 21 sections in the 2000K DLG data. The finer resolution stuff is not a complete data set. It is handled by 4 regional ESIC offices; I called EROS Data Center to find out the name and number of the regional office that handled my particular area. The regional office has a listing of what's available. Prices seem to be the same as for the coarse data, but of course you'd need more files for the entire country. I'm told (by a source at the Texas Water Commission) that if your particular area of interest has not yet been digitized and is not on the schedule, you can get it added to the schedule if you're willing to share the digitizing cost. A colleague told me that turnaround time for orders ranges from 2 weeks to 3 months. -- Hal Mueller hmueller@cssun.tamu.edu n270ca@tamunix (Bitnet) Graduate Student, Department of Computer Science Research Assistant, Department of Wildlife and Fisheries Science Texas A&M University, College Station, TX 77843
littauer@uts.amdahl.com (Tom Littauer) (03/22/90)
In article <4636@helios.TAMU.EDU> hmueller@wfsc4.tamu.edu (Hal Mueller) writes: > >For some areas of the country finer resolution data is available. DLG >exists at 1:100 000 scale. DLG and DEM exist at 1:24 000 scale (a 7.5' >quad map). DLG for hydro and transportation exists at 1:100K for almost all of the country (a few small holes). It costs ~$60K and occupies ~20GB of disk. We based our UniForum demo on this data, so I know :-) It was fun to have some guy walk up and say OK, show me Toad Suck Arkansas and be able to pull up a map of it and the neighborring smaller town, Toad Suck Ferry. >The finer resolution stuff is not a complete data set. It is handled >by 4 regional ESIC offices; I called EROS Data Center to find out >the name and number of the regional office that handled my particular >area. The regional office has a listing of what's available. Prices >seem to be the same as for the coarse data, but of course you'd need >more files for the entire country. The USGS is quite helpful at figuring out what files you need to cover the area you're interested in, and can coordinate in the case of bizaare requirement like ours was (you want *WHAT*?). You're quite right in saying that decoding the data and figuring out which file it's in is "interesting". Have fun, Tom Littauer -- UUCP: littauer@amdahl.amdahl.com or: {sun,decwrl,hplabs,pyramid,ames,uunet}!amdahl!littauer DDD: (408) 737-5056 USPS: Amdahl Corp. M/S 278, 1250 E. Arques Av, Sunnyvale, CA 94086 I'll tell you when I'm giving you the party line. The rest of the time it's my very own ravings (accept no substitutes).
hmueller@wfsc1.tamu.edu (Hal Mueller) (03/22/90)
In article <a4AH028A94vK01@amdahl.uts.amdahl.com> littauer@amdahl.uts.amdahl.com (Tom Littauer) writes: > >DLG for hydro and transportation exists at 1:100K for almost all of the >country (a few small holes). It costs ~$60K and occupies ~20GB of disk. >We based our UniForum demo on this data, so I know :-) It was fun to have >some guy walk up and say OK, show me Toad Suck Arkansas and be able to >pull up a map of it and the neighborring smaller town, Toad Suck Ferry. > What's your opinion of the quality of data in 1:100K, vice 1:24K? For our application we can get 1:100K nearly free, but if we want 1:24K we'll have to digitize ourselves (no money to pay USGS, and the quads we want aren't available yet). Project is a wildlife/habitat simulation; map is just a base map, to which we'll add vegetation types and other domain-dependent stuff. -- Hal Mueller hmueller@cssun.tamu.edu n270ca@tamunix (Bitnet) Graduate Student, Department of Computer Science Research Assistant, Department of Wildlife and Fisheries Science Texas A&M University, College Station, TX 77843
littauer@uts.amdahl.com (Tom Littauer) (03/23/90)
In article <4640@helios.TAMU.EDU> hmueller@wfsc1.tamu.edu (Hal Mueller) writes: > >What's your opinion of the quality of data in 1:100K, vice 1:24K? How long is a piece of string? :-) > Project is a wildlife/habitat >simulation; map is just a base map, to which we'll add vegetation >types and other domain-dependent stuff. I'm afraid this doesn't tell me enough about the project to advise you. If you want terrain, DLG doesn't have any. If you're looking to locate your domains by using known road and stream features as benchmarks you can easily get to within small tens of feet - the USGS descriptions will tell you exactly. I know it's easy to small tens because of all the folks who used our demo to get the LatLon of Granny's chair on the porch :-) or their bedrooms. If you have further questions, send me email or call - although I suspect the rest of the gang would be interested in a summary of the project, detailed discussion would probably get old. >Hal Mueller hmueller@cssun.tamu.edu n270ca@tamunix (Bitnet) >Graduate Student, Department of Computer Science >Research Assistant, Department of Wildlife and Fisheries Science >Texas A&M University, College Station, TX 77843 Hmmm, Aggies... I'm the guy who helped you guys install our mainframe UNIX, UTS, back in '84. -- UUCP: littauer@amdahl.amdahl.com or: {sun,decwrl,hplabs,pyramid,ames,uunet}!amdahl!littauer DDD: (408) 737-5056 USPS: Amdahl Corp. M/S 278, 1250 E. Arques Av, Sunnyvale, CA 94086 I'll tell you when I'm giving you the party line. The rest of the time it's my very own ravings (accept no substitutes).