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3

See National Grid Reference Converter for help on the precision of OSGB map references. If you just use a search range to create a box surrounding your query point, as indicated by (east_QP - range) <= east <= (east_QP + range) (north_QP - range) <= north <= (north_QP + range) a variation on your pseudo code, it is fast but biased. If you ...


2

This way it works: For Easting, subtract 108 000 000 from lng, and divide by 600 000 For Northing, subtract 54 000 000 from lat, and divide by 600 000: lng lat E N 177514245 34726053 115,857075 -32,123245 177513828 34726948 115,856380 -32,121753 177508930 34829424 115,848217 -31,950960 177508084 34829842 ...


2

Make XY Event layer doesn't create a shapefile, it's only a virtual layer. You have to export your event layer for that to happen. Try using arcpy.FeatureClassToFeatureClass_conversion().


3

Upper left is the NW corner. The negative Y pixel size is to do with storing pixels from the top down while measuring the other way.


1

It is possible to get tick marks just along the edge of the map object's frame, just a little fiddly: Check 'Show Grid' in the map's Item Properties. Set the grid interval to whatever you want (some multiple of your real world units e.g. 1,000m or whatever). This will give you a complete grid, but don't worry - we'll fix that... Set 'Frame Style' to 'No ...


6

You can use the GDAL Python bindings. Examples on how to use it can you find here. For example you create points with lat/lon like this from osgeo import ogr # first import the library point1 = ogr.Geometry(ogr.wkbPoint) point1.AddPoint(13.381348,52.536273) # Berlin point2 = ogr.Geometry(ogr.wkbPoint) ...


1

GDAL/OGR should be enough for you. http://www.gdal.org/ogr/classOGRGeometry.html


2

A For Loop automatically adds to or subtracts from the counter variable. You are subtracting one from it and then the loop itself subtracts one from the counter. That's why it skips every second records in your table. If you are sure all your records are polylines and that noe of them have more than one segment, you can do this in a single update ...


2

Alan I would recommend that you insert the start and end coordinates as separate rows in your table. In that way you can create points for these individually like explanined below. I'm assuming that you have already: - created your new table - made this new table mappable - read the coordinates from the polyline into varialbes called fX1, fY1, fX2, fY2 ...


1

Rather than linking the two together, why don't you use the OpenLayers plugin which allows you to view Google satellite imagery in QGIS? You can then edit and save your data in Q as a KML (right click save as on your layer) and import into Google Earth if required for fly through's / oblique screenshots etc.


1

It depends on how you are adding the data from Excel. If you are importing your data as a Delimited Text layer, there is a little check box on the 'Create Layer from a delimited Text File' dialog box (under layer settings) called Watch File. Check this box and it makes QGIS watch for changes in the file. In other words, as you add and save data in the ...


8

Using QGIS, you can use the SwapXY plugin. You can also do this with GDAL/OGR: https://trac.osgeo.org/gdal/wiki/FAQVector#HowdoIflipcoordinateswhentheyarenotintheexpectedorder


0

With a table in UTM SELECT ST_X(table.geometry) AS X1, --point x ST_Y(table.geometry) AS Y1, --point y ST_X(ST_TRANSFORM(table.geometry,4674)) AS LONG, -- longitude point x SIRGAS 2000 ST_Y(ST_TRANSFORM(table.geometry,4674)) AS LAT, --latitude point y SIRGAS 2000 ST_ASTEXT(table.geometry) AS XY, --wkt point xy ST_ASTEXT(ST_TRANSFORM(table.geometry,4674)) ...


1

As a geologist, I make geological cross section using the elevations values from a DEM and the colors from a geological map, look at the pure Python solution with osgeo.gdal in Python Script for getting elevation difference between two points But now, since PyQGIS 2.x, it is easier with PyQGIS and the QgsRaster.IdentifyFormatValuefunction example with a ...


0

The support for accessing raster data via QgsRasterLayer is fairly limited: http://lists.osgeo.org/pipermail/qgis-developer/2008-September/004790.html You can access the value of an individual pixel using the identify tool: x, y = -1.535, 54.634 res = layer.dataProvider().identify(QgsPoint(x, y), QgsRaster.IdentifyFormatValue) print res.results() You ...



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