Latest Contributions by jimschmidt2

I have posted a Python script that will convert the historic USGS GeoPDF maps to GeoTiffs in UTM, NAD83 coordinates. It supercedes the multi-step process I posted here on June 27, 2013.  The script can be found at:: http://mappingcenter.esri.com/index.cfm?fa=ask.answers&q=2237 ... View more

Re: Python script correction: replace x = line[15:25] with x = line[14:25] ; otherwise coordinates for 1:250000 scale maps will be read incorrectly. ... View more

Python Script continued: Part IV:  elif line.startswith("Lo"):     x = line[15:25]     y = line[26:38]     lond = line[41:44]     lonm = line[45:47]     lons = line[48:53]     latd = line[57:59]     latm = line[60:62]     lats = line[63:68]     londd = Decimal(lond.strip(' "'))     lonmd = Decimal(lonm.strip(' "'))     lonsd = Decimal(lons.strip(' "'))     londecdeg = (londd + lonmd/60 + lonsd/3600)* -1     londdstr = "%11.6f" % londecdeg     latdd = Decimal(latd.strip(' "'))     latmd = Decimal(latm.strip(' "'))     latsd = Decimal(lats.strip(' "'))     latdecdeg = (latdd + latmd/60 + latsd/3600)* 1     latddstr = "%9.6f" % latdecdeg     buffer.append(x)     buffer.append(blnk)     buffer.append(y)     buffer.append(blnk)     buffer.append(londdstr)     buffer.append(blnk)     buffer.append(latddstr)     buffer.append(newline)     FO.write("".join(buffer)) #now reset our state     buffer = [] FI.close() FO.close() Typical output control point file  for one Historic Geotiff file looks like this: -25894.864  4211779.501 -120.044975 38.040058 -25894.864  4144998.667 -120.042597 37.438378  26704.302  4211779.501 -119.445806 38.040033  26704.302  4144998.667 -119.448256 37.438356 ... View more

Converting Historic GeoPDFs in polyconic projections to GeoTiffs geo-referenced to lat-longs in ArcMap using GDAL: Part III Appendix - Sample python script for creating ArcGIS compatible Control Point tables: ControlPoints.py:     import glob from decimal import Decimal list_of_files = glob.glob('C:\Gtiffinfo1\*.txt')# create the list of file for file_name in list_of_files:   FI = open(file_name, 'r')   print FI   FO = open(file_name.replace('CA_', 'CP_'), 'w')   buffer = []   blnk = ' '   newline = '\n'   for line in FI:     if line.startswith("Up"): #Read Control Point info     x = line[15:25]     y = line[26:38]     lond = line[41:44]     lonm = line[45:47]     lons = line[48:53]     latd = line[57:59]     latm = line[60:62]     lats = line[63:68]     londd = Decimal(lond.strip(' "')) # Convert to decimal     lonmd = Decimal(lonm.strip(' "'))     lonsd = Decimal(lons.strip(' "'))     londecdeg = (londd + lonmd/60 + lonsd/3600)* -1 #Convert to decimal degrees     londdstr = "%11.6f" % londecdeg     latdd = Decimal(latd.strip(' "'))     latmd = Decimal(latm.strip(' "'))     latsd = Decimal(lats.strip(' "'))     latdecdeg = latdd + latmd/60 + latsd/3600     latddstr = "%9.6f" % latdecdeg     buffer.append(x)     buffer.append(blnk)     buffer.append(y)     buffer.append(blnk)     buffer.append(londdstr)     buffer.append(blnk)     buffer.append(latddstr)     buffer.append(newline)     FO.write("".join(buffer))   #now reset our state     buffer = [] ... View more

Converting Historic GeoPDF's in polyconic projections to GeoTiffs geo-referenced to lat-longs in ArcMap using GDAL: Part II - Create a batch file to use gdalinfo to read the header information for each GeoTiff and write it out to a text file. Run  the batch file from the MS4W shell prompt.   Example ginfoBatch.bat contents:   for /R C:\Gtiff %%f IN (*.tif) do gdalinfo.exe %%f >> C:\Gtiff\%%~nf.txt   where C:\Gtiff is the directory where the GeoTiff files are located and also where the text files will be written. Run a python script to extract the control point information from the files created in step 7, convert lat-longs coordinates to decimal degrees, and output the data to text files that can be loaded as Control Point tables with the Georeferencing toolbar in ArcGIS.   Sample Script (See Appendix): ControlPoints.py – Place the script on your desktop. Go to Start—Run—cmd to start the DOS command shell.  Change directories to your desktop (type cd desktop). Execute the python script by typing:   C:\python26\Arcgis10.0\python Controlpoints.py   Note: You may need to change the command to reflect your current version of python.   Output files with control point information will be re-named to start with CP instead of CA. If you are working with files from a state other than California, edit the ControlPoints.py script to rename as desired.   Note also that the ControlPoints.py script expects the control point information in the Gdalinfo output files to be in a fixed format. If that format varies, the script may not extract the correct control point data.   To change the georeferencing of the geotiff files created in Step 5 from Polyconic to geographic, load each geotiff file into ArcGIS. Set the Data Frame coordinate system to Geographic – NAD27.   Load the Georeferencing Toolbar. Make sure the Layer shown on the toolbar is the layer you want to georeference. Click on the View Link Table button. In the Table window, click on the Load button and select the proper Control Point file (starting with “CP”) for the geotiff file shown on the georeferencing toolbar (The Control Point files were created in Step 8). Ignore any warning messages about collinear points.  Click OK.     On the Georeferencing Toolbar dropdown menu, select Update Georeferencing. Note: If Update Georeferencing is greyed out, try Update Display first.   ... View more

Here's one way to convert Historic GeoPDF's in polyconic projections to GeoTiffs geo-referenced to lat-longs in ArcMap using GDAL. Part1   Download the historic maps desired in geo-pdf format using the National Map Viewer.   Unzip the files.   Remove any spaces in the pdf filenames.   Install a software package that includes GDAL (Geospatial Data Abstraction Library). I installed MapServer for Windows (MS4W) version 3.0.6 (http://www.maptools.org/ms4w/index.phtml?page=downloads.html).   Create a batch file to use the GDAL translate utility to convert the PDF’s to GeoTiffs. (Example: gtiffBatch.bat)   for /R C:\USGS_Topos1 %%f IN (*.pdf) do gdal_translate.exe  -of GTiff %%f C:\Gtiff\%%~nf.tif   where C:\USGS_Topos1 is the directory where I have the pdf files and C:\Gtiff is the output directory where the GeoTiff files will be written. %%f is the filename wildcard.   Open the MS4W shell script window (should be an icon on your desktop once installed). Type gtiffBatch.bat  (see above) to execute the batch file.  It will process all the pdf files in the source directory and write out the GeoTiff files to the destination directory. It takes about 10 seconds per file to do the conversion. Note: If you are not dealing with Historic maps in the polyconic projection, you can stop here. The GeoPdfs should be useable in ArcMap as is. ArcGIS does not recognize the polyconic projection, so you need to do the following steps to convert the GeoTiffs to a lat-long georeferencing scheme.       ... View more