408 reputation
15
bio website bhell.net
location Sweden
age
visits member for 1 year, 11 months
seen Mar 11 at 13:15

May
22
comment Leaflet proj4leaflet with multiple projections
You are missing one problem: One coordinate unit in plate carrée (say one degree) does not have the same length in N-S and E-W direction. In Sweden (where I live), a degree in longitude is about half the length of one degree in latitude. That means that a 1x1 degree square is not at all a square in reality. To cover a (real) square with plate carrée squares here, you actually need about two such squares next to each other (for simplification consider "Web Mercator" to resemble reality in this case). This means that the tiles will not align.
May
21
comment Leaflet proj4leaflet with multiple projections
I'll add some more stuff to my previous answer.
Feb
11
comment How to create contour from NetCDF?
ArcGIS can read NetCDF directly as raster data, so there is no need to modify the dataset by interpolation, kriging etc.: help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/…
Feb
10
comment How to create contour from NetCDF?
NetCDF is a standard raster format, so I don't understand what you mean with creating a raster of it. It would help if you could clarify what you tried and what you could not achieve.
Dec
14
comment How can I get nearest road to a lat lon in MSSQL?
According to the documentation, STDistance works with geography, not geometry points. As distances are calculated differently for geographical and cartesian coordinates, the result may be unexpected (I don't have access to a DB right now to test myself). If you stick to one coordinate system (which you should because of computation overhead for re-projecting), there is no need for another DBMS here. PostGIS, Oracle Spatial and SQL Server Spatial are all very capable solutions, and have all their own advantages and disadvantages.
Dec
14
comment How can I get nearest road to a lat lon in MSSQL?
The stackexchange thread which I linked to has a complete example. As I mentioned, this is not a trivial query, and it will depend on how your data model looks like.
Dec
13
comment How can I get nearest road to a lat lon in MSSQL?
In that case you could filter your data with the shown map extent first, and then run the STDistance query on the result.
Dec
13
comment How can I relate between street and city in OSM imported data into SQL?
You would need a Cities table with at least attributes for name and spatial extent (as a polygon). Then you would perform a join between Streets and Cities based on spatial overlap/contains. The query result is all roads with a corresponding city name attribute. For a single city the documentation example for STOverlaps should be very close to your needed query.
Dec
13
comment How are you, as GIS professionals, spending most of your day at work?
I like the xkcd part, which is very relevant for us who do a lot of Python programming. More field work would be nice, too... For me it's meetings, research, testing, writing reports etc.
Dec
12
comment Fast data representation on the vector layers
Thanks for posting the link to the article! I don't think that OL supports <canvas> rendering yet. However, they state that their code could be ported to OL. Apart from that wouldn't it make more sense to do the simplification at server level, i.e. in WFS? Why lift all that data over to the client, to then not show it?
Dec
11
comment How to speed up queries for raster databases?
Multiband rasters will likely help if you need to query the same pixel's value for several months at the same time (to stick with your example), e.g. to analyse time series. The query in the question only retrieves one specific date. If the date was contained in one band, the DBMS would need to read all the other bands as well, even though they are of no interest for answering the query. This would probably deteriorate performance.
Dec
11
comment How to speed up queries for raster databases?
How did it not work? No noticeable performance gain, or other problems? If you have a table column which regularly appears in a WHERE clause, you should always consider indexing it. It will not only help in this case if you have many distinct dates (i.e. a large value domain) but also if you have a large number of records in the table.
Dec
11
comment How can I improve my Georeferencing results?
I'm wrong: Mercator of course should have parallel meridians. Maybe van der Grinten?
Dec
11
comment How can I improve my Georeferencing results?
That should be a Mercator projection (the parallels are not equidistant).