GIS
Raster overviews: faster display with explicit analytical limits
Overviews are reduced resolution representations of a raster used to support efficient viewing or selected access patterns.
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THE DRONE COLLAB JOURNAL
Better drone maps start with better decisions.
Explore practical photogrammetry, GNSS, IMU, GIS and remote sensing methods. Technical explanations, worked examples and field checks for the people turning aerial photographs into usable maps.
1554 articles13 topics
Flight planning
Terrain-Following Capture for Coastal Settlement Corridors
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GIS
Cloud Optimized GeoTIFF for practical map delivery
A Cloud Optimized GeoTIFF arranges tiled raster data and overview information so a compatible reader can request useful subsets without transferring the whole dataset.
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GIS
GeoTIFF georeferencing: pixels, transforms, and coordinate meaning
A georeferenced raster combines numeric bands with a relationship between pixel positions and geographic coordinates.
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GIS
CRS metadata in exported mapping files: preserving the full definition
Coordinate metadata connects stored numbers to a geographic interpretation.
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GIS
Ground distances and grid distances: understanding projection scale
A distance measured in a projected grid is not automatically the physical ground distance measured by a survey instrument.
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GIS
Reproducible coordinate transformations with PROJ operations
A source and destination CRS pair can have several candidate coordinate operations, distinguished by area, accuracy description, required grids, or reference assumptions.
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GIS
Coordinate epochs and changing reference frames for repeat surveys
A coordinate can depend on the reference frame and the time at which it applies.
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GIS
Local engineering grids and site coordinates in drone mapping
A local engineering grid may use an arbitrary origin, rotation, scale, or shortened coordinates chosen for a site.
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GIS
Ellipsoid heights, geoid models, and orthometric elevation
GNSS commonly provides height relative to a reference ellipsoid, while many practical elevation systems describe height relative to a gravity related surface.
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GIS
Mapping across projection zone boundaries without breaking the analysis
A projection zone boundary is an administrative division of a coordinate system family, not a physical discontinuity in the landscape.
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GIS
Choosing a UTM zone for a local drone mapping deliverable
UTM is a family of projected coordinate systems organized by longitude zones and hemisphere.
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GIS
Longitude, latitude, and axis order in geographic data exchange
Geographic coordinates can be presented in different axis orders depending on the CRS definition, file specification, and software interface.
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