Historical Aerials
There are 5 sets of historical aerials ranging from 1942 to 1984. All but 1952 consist of two separately acquired sets of images. All data is from TNRIS. The relatively new ability of arcmap to generate seamlines between images has made trimming and color adjusting unnecessary (may look better, but not worth the time required)
| Year | # Imgs | Status | Georef'd | Trimmed | Color adjusted |
|---|---|---|---|---|---|
| 1942 | 8 | complete | Yes | Yes | Yes |
| 1952 | 1 | complete | Yes | Yes | Yes |
| 1964 | 37 | incomplete | Yes | Partly | N/A |
| 1972 | 17 | incomplete | Yes | Yes | N/A |
| 1984 | 34 | incomplete | Yes | Yes | N/A |
Creation Process
- Remove borders
- either a simple crop, or color everything outside the image white and crop to the non-white area
- In ArcMap: Layer Properties > Symbology > Display Background Value: 255 as [no color]
- either a simple crop, or color everything outside the image white and crop to the non-white area
- Load the tiffs into arcmap
- Can just drag and drop
- Georeference
- Open the georeferencing toolbar
- Select the layer
- Add Control points
- Adjust transformation type
- Georeferencing > Update Georeferencing
- Cut out bad parts
- Remove borders, damaged areas, and areas which are better quality in a different image
- Adjust levels
- Correct light and dark areas along the edges and in the corners
- Adjust levels between adjacent images to hide their border
- Convert to Mosaic Dataset
- ArcToolbox > Data Management Tools > Raster > Mosaic Dataset
- Create Mosaic Dataset
- Add Rasters To Mosaic Dataset
- Build Seamlines
- Set Mosaic Dataset Properties
- Set mosaic method to seamline and optionally the operator to blend
- Build Overviews
- Define Mosaic Dataset NoData - use 255 (white)
- Color Balance Mosaic Dataset (optional)
- requires Raster Properties -> Build Pyramids And Statistics
- ArcToolbox > Data Management Tools > Raster > Mosaic Dataset
