Tag Info

New answers tagged

0

Go to Settings, select Transformation Settings. Change the name of the output raster to your new filename. Click OK. Now run your transformation.


0

I learned that ArcGIS has a georeferencing feature called autoregistration that performs this task with some caveats. They say it does not work well in my use case of old scanned maps. QGIS has no similar feature, so I wrote a script in Python using the OpenCV library that looks for general image similarity, maps the correspondence, and then transfers ...


0

It is hard to answer, since ESRI code is not exposed as far as I know, thus the algorithm can't be analysed. However, there is a fundemental flaw in your question, that is for shift you should use only 1 GCP: "A zero-order polynomial is used to shift your data. This is commonly used when your data is already georeferenced, but a small shift will better line ...


3

You should take into mind two main notions: Spatial adjustment is a complex and multistep process. You should find reliable anchors to which you should adjust the vector layer. On a raster, such as a basemap, such a process can be much more complex since of raster resolution and accuracy problems, in paticular when using a base map. Don't hesitate to use ...


0

Thin plate spline works perfectly for all GCP you have entered, but possibly not for the rest of the image. If you use polynomial interpolation, you get residuals for all GCP points. If one or several of your GCP have a low accuracy, the polynomial interpolation can compensate that, leaving the image as a whole with less distortion. With TPS and one GCP ...


0

first of all, I did a test in my own account and it seems to be working: https://team.cartodb.com/u/iriberri/tables/italy_names/table Some things for you to take into account: Try to avoid leading spaces after your city names. "Pavia " instead of "Pavia" will make the system fail at the moment. Obviously this is a bug we will fix asap. The ...


1

See Georeferencing Topo Sheets and Scanned Maps.


1

For maps that are 100 or more years old, you should not expect too much accuracy. The surveyeors of old times did not have high-precision GPS receivers. As a consequence, polynomial interpolation is better than thin plate spline, because it averages over all GCPs you enter, while the latter considers the GCPs as exact. Try to gather as much GCP you can ...


0

As long as all of your images share the exact same extent, origin, and cell size, they would be considered co-registered meaning they perfectly align to each other. In this case, yes, you can georeference one of them and then apply the exact same control points / georeferencing information / transformation to all of the remaining rasters and they should come ...


1

gdalwarp -geoloc allows you to use the complete 2d-array of latlon as georeference. With that, you can use any target CRS to reproject your data to a commonly used projection. See my answer to this question for an example: How to match a raster NetCDF data with a vector layer in QGIS?


0

Your table is already georeferenced! Go to "Map view" to see the geometries. :-) (Check that your "the_geom" column contains rows of type Polygon and that the cartodb_georef_status column is set to true. If you want to run another georeferenciation process in your table, because for example not all your rows were correctly geocoded, make sure you delete the ...


0

Just try to check the Spatial Reference of your image. If there is no spatial reference set for your image, try to define its spatial reference.



Top 50 recent answers are included