General Use Instructions

Getting Started ›› GIS Images ››
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Required Software

A user intending to use image data must have appropriate software such as ArcGIS or ArcGIS Explorer Desktop to view the images. ArcGIS Explorer Desktop is available for free download from the following website: http://www.esri.com/software/arcgis/explorer/index.html.  Windows Web browsers can view MrSID images when the Express View Browser plug-in (also known as MrSID Browser plug-in) is installed. The Express View Browser plug–in can obtained form www.lizardtech.com


Download


There are four files that make up each image, .sdw, .sid, .sid.aux.xml and one optional file .aux. You must download all available files. There is an Image Key map in each folder you can review to help you select the correct Image file.


The Image Data is located:  ftp://ftp.polkpa.org/GISData


Single Click the year you need. This will open a list of files available. Right click on the file you want to download, Choose Save Target As to save the file to your computer's hard drive. Keep the original file name. You will have to choose the directory where you want to save the file. The files, .sdw, .sid, .sid.aux.xml and .aux files (if available), must be saved to the same folder.


Repeat the steps above to download all files you need for your project.


Digital Orthophotography and Mapping Specifications:


Horizontal Coordinate System

Florida State Plane Coordinate System, Florida West Zone (0902)

North American Datum of 1983/HARN, US Survey Feet


2001 Images

1” = 100’ National Map Accuracy Standards

Negative Scale 1”=833’

Resolution = One foot pixel resolution

Date of Aerial Photography = March 2001


2002 Images

1” = 200’ National Map Accuracy Standards

Negative Scale 1”=2640’

Resolution = Two foot pixel resolution

Date of aerial photography = February 2002


2005 Images

1’= 100’ National Map Accuracy Standards

Negative scale 1”=833’

Resolution = One foot pixel resolution

Date of aerial photography = February 2005


2007 Images

1’= 100’ National Map Accuracy Standards

Negative scale 1”=833’

Resolution = One foot pixel resolution

Date of aerial photography = February/March 2007