Search USGS⌕ Search

Geology topics

L. J. Ladner

Publications and source records attributed to L. J. Ladner.

3 recordsLinked to original sources
USGS1992

Implementation of softcopy photogrammetric workstations at the US Geological Survey

The US Geological Survey has provided the Nation with primary quadrangle maps and map products for the last 50 years. The Survey recently completed initial coverage of the conterminous United States and Hawaii at 1:24 000 scale. In Alaska, complete coverage exists at 1:63 360 scale. Effort is underway to build a National Digital Cartographic Data Base (NDCDB) composed of the digital representation of these and other map series. In addition the Survey plans to meet the demand for more current and complete data through the development and promotion of spatial data standards in cooperation with other Federal, State, local and private organizations. -from Authors

Photogrammetric Engineering and Remote Sensing↗
USGS1989

Image processing techniques for digital orthophotoquad production

Orthophotographs have long been recognized for their value as supplements or alternatives to standard maps. Recent trends towards digital cartography have resulted in efforts by the US Geological Survey to develop a digital orthophotoquad production system. Digital image files were created by scanning color infrared photographs on a microdensitometer. Rectification techniques were applied to remove tile and relief displacement, thereby creating digital orthophotos. Image mosaicking software was then used to join the rectified images, producing digital orthophotos in quadrangle format.

Photogrammetric Engineering and Remote Sensing↗