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USGS Topographic Maps: Converting GeoPDF to JPEG2000

USGS Topographic Maps: Converting GeoPDF to JPEG2000

After more than 60 years, the USGS topographic maps still provide an excellent way to explore the United States. The content and symbology are consistent and easily recognizable, and they serve both as a reliable data source and a basemap. Since 2009 the USGS has begun offering the US topographic maps through a new map series called US Topo. The US Topo Map program shares topographic maps based on GIS data in GeoPDF format. These GeoPDFs serve as a nice, standalone products, but lacks certain functionality desired by the GIS community. By converting these GeoPDFs into a more useable format, such as JPEG2000, it is possible to create a seamless mosaic of an area, providing an unbroken view of multiple topographic maps and a great basemap option.

This posting compliments the "Working with USGS Topographic Maps: Converting GeoPDF to GeoTIFF" in the fact that it provides the option of using another storage format. While GeoTIFFs are a high-quality raster storage format, they require large amounts of disk space. JPEG2000s provide the same high-quality raster appearance, but require significantly less disk space than the GeoTIFFs.

This post assumes that you have access to Global Mapper v15 and Esri ArcGIS for Desktop 10.2.2, and a basic knowledge of how to use them.

First, download the US topographic maps for your area of interest. You can find instructions on doing this in the “Using the National Map Viewer to Download US Topo Maps” blog posting.

 The next step is to transform the GeoPDFs to GeoTIFFs. To do this, we will use Global Mapper 15 and the following script, which was modified from an existing USGS workflow document; the shapefile template needed to remove collars from the US Topo maps can be downloaded at the following link.

    As you can see above, the Export “TYPE” has been changed to JPEG2000 from GeoTIFF.

     

    Here is some more important information about this script:

    1. This script is designed to convert GeoPDFs to GeoTIFFs, however it can be easily edited to output both collared and collarless JPEG2000s (JP2s). The script will create two outputs from the input GeoPDFs – 1) collared JP2s and 2) collarless JP2s.
    2. This script will create and store the output JP2s in the same folder as the original GeoPDF files.
    3. This script will maintain the original coordinate system of the GeoPDFs. All GeoPDFs are stored in the UTM Coordinate System – in this case, the Assateague Island topographic maps are stored in UTM Zone 18N.
      1. To run the script:
        1. Make sure the file extension is set to .gms so that Global Mapper will recognize the script.
        2. To successfully run this script, place it within the same folder as the original GeoPDF files.  It will also be necessary to place the All_7.5min_cells.shp (part of the file download at the above link) and accompanying files into the folder containing the original GeoPDFs.
        3. Within Global Mapper, click the File tab at the top of the page, and scroll down to Run Script.

    1. Browse to the correct folder and select your script with the .gms extension. Click OPEN.
    2. This will open the Script Processing Window. In the top half of the window you can view your script. In the bottom half of the window you will see the results of your script. This is where you will see a running ‘commentary’ of the script as it successfully (or unsuccessfully) processes.

     

    1. Finally, click RUN SCRIPT at the bottom of the Script Processing Window.
      1. Depending on the amount of GeoPDFs and your computers processing speed, this process could take an hour or more.

    When the script has completed running, bring one of the newly created collared and collarless JP2s into ArcMap to ensure that the script correctly processed the images.  

    If you have no border area around your collarless JPEG2000s, then you are finished. If you HAVE a border area, please proceed to the next step. Please note that the border are may be very small; it may be necessary to zoom into the edges of your topo map to see them.

    To check if you have a white border area, please change the background color of the data frame to a non-white color. To do this, follow these steps:

    Double click on the Layers heading the Table of Contents (red circle) and navigate to the Frame tab (purple circle). In the Background dropdown menu, choose a non-white color (green circle).

    Now, we will begin removing the “residual collar” from the collarless JP2s for your area of interest (AOI).

    Note: This method will result in a seamless, borderless mosaic. However, there will be (in some cases) a slight black border remaining along the OUTSIDE edges of the outer quadrangles in your AOI.

    First, add all newly created collarless JPEG2000 files to your map document. There should be some slight overlap border areas.

    Open the Image Analysis Window from the Windows menu at the top of your screen.  

    1. Select all rasters in the top pane of the Image Analysis window, then select the Min mosaic operator from the first drop down menu in the processing section (red circle) and then click the Mosaic button (green circle).

    1. Next, use the Draw tool to draw a polygon around the perimeter of the mosaicked image.
      1. Be sure to zoom in at corners and ensure that only a slight portion of the edge is exposed (see example below).
        1. It is possible to edit the vertices of your drawn polygon by clicking on the Edit Vertices button (purple circle below) on the Draw toolbar.

    Once you have completed drawing your polygon, it will be necessary to Clip the mosaicked image. To do this, select the mosaicked image in the Image Analysis window. Ensure that the polygon you just created is also selected, and then click the Clip icon. See below.

    Now, search for the Split Raster tool in the Data Management toolbox. Fill in the following options in the tool dialog:

    1. Input = Temporary Mosaic created via Image Analysis window
    2. Output Folder = Select location for files to be written.
    3. Output Base Name = Select the appropriate base name for your output rasters.
    4. Split Method = NUMBER_OF_TILES
    5. Output Format = JP2
    6. Resampling Method = BILINEAR
    7. Number of Output Rasters = This will depend on how many quadrangles you have in the X and Y direction. This tool will split the rasters along these specifications.
    8. Click OK to run.

    Please note that ArcMap automatically stretches these images (for collared and collarless images). To remove this stretch select one of the following two options when you have finished processing:

    Option 1: Open the Properties of each image and select the Symbology tab and change Stretch Type to None.

    Option 2: Create a batch process with the “Set Raster Properties” tool (Data Management toolbox) and select “Processed” from the Data Source Type dropdown menu.

    Once the process of removing the residual collars has been completed, you should have a seamless collection of topographic maps that can be added into a mosaic dataset for easy, seamless viewing and simple sharing.

    For more information on creating a mosaic dataset, please refer to the “Processing Imagery with Mosaic Datasets to Create Functional Outputs” document. The addition of these final products to a mosaic dataset will allow the user to further control the appearance of the topographic maps. Please refer to the above workflow for more information.

     

    This blog posting was developed with the support of a competitive grant (cooperative agreement number P09AC00212; task agreement number P13AC00875) from the National Park Service in partnership with the North Atlantic Coast Cooperative Ecosystems Studies Unit. It is part of a larger document available for download on the IRMA Portal.​

     

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    Authored by

    erica
     

    Last updated

    08/04/2016 - 09:55