This data set is a mosaic made from aerial photographs acquired from the Modoc National Forest with photo dates throughout the summer of 1946. The 126 original photographs were scanned and orthorectified in December 2002. The aerial photographs were scanned and orthorectified by the Geographical Information Center, California State Univ., Chico, using PCI Ortho software in December 2002. The mosaic was created in September 2004. Additional mosaic reformatting was done in 2005 and 2020 by the California Department of Fish and Wildlife.

This data set is a mosaic made from aerial photographs acquired from the Modoc National Forest with photo dates throughout the summer of 1946. The 126 original photographs were scanned and orthorectified in December 2002. The aerial photographs were scanned and orthorectified by the Geographical Information Center, California State Univ., Chico, using PCI Ortho software in December 2002. The mosaic was created in September 2004. Additional mosaic reformatting was done in 2005 and 2020 by the California Department of Fish and Wildlife.

This is a layer of aerial photos acquired from the Modoc National Forest with photo dates throughout the summer of 1994, scanned and orthorectified by the Geographical Information Center, California State Univ., Chico, with later processing by the California Department of Fish and Wildlife.It documents the location of aspen stands. It also provides the visual background for the display of polygons and the visual comparison of similar and more recent data sets. This is one of five data sets for a study investigating change in the size of aspen stands since 1946. Other available data sets are a 1946 aerial photo mosiac, interpreted polygons of individual aspen stands from 1946 and 1994, and a sample of aspen stand characteristics in 98 stands from 2002. Geographic extent of the imagery: The study area is the Warner Mountains south of State Highway 299.

This is a layer of aerial photos acquired from the Modoc National Forest with photo dates throughout the summer of 1994, scanned and orthorectified by the Geographical Information Center, California State Univ., Chico, with later processing by the California Department of Fish and Wildlife.It documents the location of aspen stands. It also provides the visual background for the display of polygons and the visual comparison of similar and more recent data sets. This is one of five data sets for a study investigating change in the size of aspen stands since 1946. Other available data sets are a 1946 aerial photo mosiac, interpreted polygons of individual aspen stands from 1946 and 1994, and a sample of aspen stand characteristics in 98 stands from 2002. Geographic extent of the imagery: The study area is the Warner Mountains south of State Highway 299.

This is a layer of aerial photos acquired from the Modoc National Forest with photo dates throughout the summer of 1994, scanned and orthorectified by the Geographical Information Center, California State Univ., Chico, with later processing by the California Department of Fish and Wildlife.It documents the location of aspen stands. It also provides the visual background for the display of polygons and the visual comparison of similar and more recent data sets. This is one of five data sets for a study investigating change in the size of aspen stands since 1946. Other available data sets are a 1946 aerial photo mosiac, interpreted polygons of individual aspen stands from 1946 and 1994, and a sample of aspen stand characteristics in 98 stands from 2002. Geographic extent of the imagery: The study area is the Warner Mountains south of State Highway 299.

TIME PERIOD COVERED These data were collected between May-July 2004 by field crews working for California Department of Fish and Game. GEOGRAPHIC EXTENT OF THE RECORDS Vegetation plots occur in two study areas on public lands in Yuba and Tehama Counties in the Sierra Nevada foothills. NUMBER OF RECORDS There are 183 records with habitat attributes measured from 0.05 - 0.10 hectare sampling plots. BASE DATA STRUCTURE The file is a flat Excel table which gives vegetation attributes for each habitat plot. Each habitat plot is represented by two key fields called "SAMPLE_ID" and "PLOT_NUM" which relate these habitat records to bird and herpetile survey data collected in the same year from the same sample points. WHAT EACH RECORD REPRESENTS Each record in the table represents the average values for habitat attributes from plots that can be linked with bird count data from the same points. Average values for each sample represent the mean of average values from 3 habitat plots measured at each point.

This dataset displays aspen stands in the Warner Mountains south of State Highway 299. The 1946 and 1994 data are presented as polygons depicting aspen stands derived from aerial photos taken in 1946 and 1994, respectively, while the 2002 data includes the aspen stand delineations and their corresponding vegetation data (i.e., size distribution of aspen, the canopy and shrub cover, the number of species of grasses and forbs, and the ratio of conifers to aspens). The polygons ranged in size from less than 0.2 acres to more than 1,130 acres. There are 2103 records, one for each aspen stand mapped and sampled. All data were collected and summarized by Aaron Di Orio, California Department of Fish and Wildlife. This is one of three data sets for a study investigating change in the size of aspen stands since 1946. Other available data sets are 1946 and 1994 aerial photo mosaics.

TIME PERIOD COVERED These data were collected between May-July 2004 by field crews working for California Department of Fish and Game. GEOGRAPHIC EXTENT OF THE RECORDS Vegetation plots occur in two study areas on public lands in Yuba and Tehama Counties in the Sierra Nevada foothills. NUMBER OF RECORDS There are 183 records with habitat attributes measured from 0.05 - 0.10 hectare sampling plots. BASE DATA STRUCTURE The file is a flat Excel table which gives vegetation attributes for each habitat plot. Each habitat plot is represented by two key fields called "SAMPLE_ID" and "PLOT_NUM" which relate these habitat records to bird and herpetile survey data collected in the same year from the same sample points. WHAT EACH RECORD REPRESENTS Each record in the table represents the average values for habitat attributes from plots that can be linked with bird count data from the same points. Average values for each sample represent the mean of average values from 3 habitat plots measured at each point.

Contains a comprehensive listing of all spatially catalogued photographs collected during mobile habitat surveys by Program field staff. Current dataset is for 2002-2007.

This data release publishes datasets of historical aerial photograph orthomosaics covering areas within and surrounding Lassen Volcanic National Park, California. The historical imagery provides a high-resolution, spatially contiguous record of the park’s landscape across six dates ranging from 1941-2004. A total of 990 hard-copy aerial photographs taken in 1941, 1952, 1966, 1973, 1998, and 2004 were scanned at 800 dpi with an Epson Expression 12000XL. The 1941-1966 images are in black and white and scanned in 16-bit greyscale, and 1973, 1998 and 2004 are in color and scanned as 24-bit RGB. Like many historical aerial photograph collections, most of the flight and camera parameters were missing; Structure-from-Motion (SfM) software offers an efficient solution for orthorectifying images that lack these parameters. We used a SfM software called Agisoft Metashape Professional (v.1.6) to generate the orthomosaics for each image year, which were aligned with sets of reference Ground Control Points (GCPs). Average Root Mean Square Error (RMSE) ranged from 4.07-140 cm, and average reprojection errors ranged from 0.56-0.78 meters. Each orthomosaic metadata file contains specific information on image processing, number of GCPs used and estimated error.