Cannot Project .TIF and .TFW

adrufadruf Global Mapper UserPosts: 17Trusted User
edited November 2014 in Raster Data
I have attempted to load the Queen Anne’s County-wide FIRM Panels (Under Effective Products) .TIF files available here: FEMA Flood Map Service Center | Search All Products

However, Global Mapper v14.2 (64-bit) hasn't been able to recognize the .tfw world files associated with these maps in order to bring them in geo-referenced. Do they also need a .prj file or what? Can someone help me AND explain? I contacted FEMA, but they said I should use ArcGIS to view the files, which I don't have.

Thanks,
Adam

Comments

  • JeffH@BMGJeffH@BMG Global Mapper Developer Posts: 337Trusted User
    edited November 2014
    Hello Adam,

    Can you tell me where you found the associated .tfw files? I didn't see them on the site.

    thanks,

    ~Jeff
  • adrufadruf Global Mapper User Posts: 17Trusted User
    edited November 2014
    They are in the .zip file you download called FIRM Panels (43)Capture.GIF
  • JeffH@BMGJeffH@BMG Global Mapper Developer Posts: 337Trusted User
    edited November 2014
    Thanks. I'll take a look. It turns out that the first entry on the list (the one that I downloaded) doesn't have a .tfw file.

    It may be that GM 14 didn't support .tfw files, so I'll need to dig back through the history.

    ~Jeff
  • JeffH@BMGJeffH@BMG Global Mapper Developer Posts: 337Trusted User
    edited November 2014
    Hi Adam,

    OK, I checked into this. This will work in GM 14. You need to go into the configuration dialog (Tools / Configure...) and under Miscellaneous Advanced Options, look for "Prefer World File (TFW) Coordinates for GeoTiff files", and make sure that that's checked. That's still not quite enough, though; you'll still need to select the projection for one of these files; you'll want UTM, Zone 18 (78W - 72W - Northern Hemisphere).

    Hope that this helps.

    Regards,

    ~Jeff
  • MykleMykle Global Mapper User Posts: 452Trusted User
    edited November 2014
    Recommend looking at one of the sheets, in the left hand marginal information, for details about datum and projection.
    For my area there are PNG and PGW files, with a datum of NAD-83 and projection of state plane in feet.

    That said, the main problem for you will be overlapping sheets, with each of them needing to be cropped. I don't know of a way to automatically crop an entire set as you can with USGS quadrangles. For my testing I had to enter the cropping boundaries manually for each sheet. These values are specified in decimal degrees, but you can enter the corner coordinates in deg min sec with spaces between values.

    My area also has sheets at different scales, so I would expect to group the sheets by scale, and order the groups with larger scale (more detail) maps on top (lower in the control panel list).
    Cheers,
    Mykle
  • adrufadruf Global Mapper User Posts: 17Trusted User
    edited November 2014
    Were you able to get it to project over an aerial? I don't know if the .TFW files are wrong or if I'm missing something, but these files must have been created with a different projection than UTM Zone 18. They appear in no-man's land when I use that projection. Thanks for getting me this far though! I appreciate your help!
  • adrufadruf Global Mapper User Posts: 17Trusted User
    edited November 2014
    Sorry Mykle, I didn't see your comment before commenting. I located this: "The projection used in the preparation of this map was UTM Zone 18. Horizontal datum was NAD 83, GRS80 spheroid." Using this projection it worked!!

    Thank you both for your help!
  • JeffH@BMGJeffH@BMG Global Mapper Developer Posts: 337Trusted User
    edited November 2014
    Yep, I was going by the info in the FEMA study PDF, available through the same site, and which agrees with the marginalia information. Lined up fine. Verified by setting white as the trasparent color in the options for the TIFF layer; you can see it pretty clearly then.

    Glad you're up and running, and thanks for the assist, Mykle!

    Cheers,

    ~Jeff
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