OC 2005 TC Ortho Image Service

<div>BY USING THIS WEBSITE OR THE CONTENT THEREIN, YOU AGREE TO THE <u><a href='https://www.oakgov.com/open-data-terms' rel='nofollow ugc'>TERMS OF USE</a></u><span style='font-family:&quot;Avenir Next W01&quot;, &quot;Avenir Next W00&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size:17px;'>. </span><br /></div><div><br /></div>Oakland County participated in the Southeast Michigan Regional Orthoimagery project encompassing approximately 5000 square miles, which includes an additional ½ mile buffer beyond the boundary of the seven county region. This extends approximately 500 feet into Canada. The orthoimagery is true color with a base pixel resolution of 6 inches for the County-only imagery. Orthoimagery tiles were delivered in Tiff format with Tiff world files representing ground dimensions of 2000' x 3000'. Tile naming convention includes the county code, the third and fourth digit of the lower left X and the first three digits of the lowerY coordinate and the year flown. For example 161 2005, tile name would be 1612932405). Countywide and community mosaics are saved in the MrSID format. Community MrSID files are compressed at 20 to 1 using the 6 inch pixel imagery and countywide MrSIDs are compressed at 50 to 1 using the 2 foot pixel imagery. All control was based on the following -Michigan State Plane (South) -Horizontal datum -North American Datum (NAD 83) international feet second-order class I. -Vertical datum - North American Vertical Datum 1988 (NAVD88) international feet, third-order class I. All imagery was taken in the spring of 2005. Acquisition was attempted when the ground was not obscured by haze, smoke, dust, clouds or cloud shadows, and snow or ice. Flights were scheduled when solar angle was at least 30 degrees or more above the horizon Orthoimagery complies with the American Society for Photogrammetry and Remote Sensing Accuracy Standards for Class 1 mapping requirements.

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奥克兰县（Oakland County）参与了密歇根州东南部区域正射影像（Orthoimagery）项目，该项目覆盖范围约5000平方英里，包含七县区域边界外额外延伸0.5英里的缓冲区，此缓冲区向加拿大境内延伸约500英尺。
本项目的正射影像为真彩色影像，仅针对奥克兰县的影像基础像素分辨率为6英寸。正射影像瓦片以标签图像文件格式（Tiff）交付，配套的Tiff世界文件的地面尺寸为2000英尺×3000英尺。
瓦片命名规则包含县代码、左下角X坐标的第三位和第四位数字、左下角Y坐标的前三位数字以及飞行拍摄年份。例如当示例代码为161 2005时，瓦片名称应为1612932405。
全县范围及社区的镶嵌影像以MrSID格式存储。社区MrSID文件基于6英寸像素分辨率的影像以20:1的压缩比进行压缩，全县范围的MrSID影像则基于2英尺像素分辨率的影像以50:1的压缩比进行压缩。
所有控制点均基于以下基准：
- 密歇根州平面坐标系（南系）
- 水平基准面：北美大地基准1983（NAD 83），单位为国际英尺，精度等级为二等一级
- 垂直基准面：1988年北美垂直基准（NAVD88），单位为国际英尺，精度等级为三等一级
所有影像均拍摄于2005年春季。影像采集时尽量避免地面被雾霾、烟尘、灰尘、云层、云影以及积雪或冰层遮挡。飞行计划安排在太阳高度角不低于30度时进行。本正射影像符合美国摄影测量与遥感学会（ASPRS）一级测绘精度标准。