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9

I haven't had a chance to test out the Nominatim and Geocoder US geocoders. My understanding though is that the Geocoder and Nominatim can't be run directly in the database, which to me is a big disadvantage because it makes them difficult to use in things like triggers or for batch updates directly in the database. PostGIS geocoder being a pure ...


9

You have to change the Coordinate Reference System of the project; QGIS won't do that when you load a shape file. Go to: settings->Project Properties->Coordinate Reference System (CRS) and search for your projection. Although WGS84 and NAD83 both refer to datums not projections. If you want to project your TIGER data, I would be inclined to use either a ...


8

You can download Census Blocks from TIGER; you'll just have to download the data on a state-by-state basis and merge it all together. EDIT: See this page for block-level shapefiles that already have the population and housing unit counts attached, so you don't have to deal with joining SF1 tables!


8

did you look at the TIGER data from the census bureau? They are available at http://www.census.gov/geo/www/tiger/


7

You can get polygon shapefiles of the US from http://www.naturalearthdata.com/. They cover the whole world.


6

UPDATE The new files are now available and known as "Cartographic Boundary Files". More detail on the other types here http://www.census.gov/geo/maps-data/data/tiger.html The County file discussed above is available here: http://www.census.gov/geo/maps-data/data/cbf/cbf_counties.html The official file is not currently available as of 5-12-2011, but ...


6

You have two ways of reducing the file size: Remove all the pretty formatting and redundant white space. In some 'XML-style' files this can be a surprisingly large amount and can easily double or even treble your file size. However I doubt it accounts for the difference in your volume and the data you link to above. Reduce the volume of actual data ...


6

Very interesting question! I'd note that the geography area calculation is extremely close (in your last example, 3 msq difference over an area of 20000000 msq. (0.000015%) Since we know that census manages its data inside Oracle Spatial, I'd guess that what you're seeing is a very small difference in the implementation of geodetic area calculation between ...


5

PLACEFP10 references an incorporated place (city, town) or Census Designated Place (CDP). COUSUBFP10 refers to a county subdivision. This can include incorporated places but not CDPs. There will "always" be an associated county subdivision but not necessarily a place. County subdivisions are frequently townships but it varies state to state. If PLACEFP10 is ...


5

You need the tables addr, addrfn, and featnames. And the geography in the edges layers. addr These are address ranges, just address ranges. They relate to feature (i.e. road) names via... addrfn A table relating address ranges and feature names. addr.ARID -> addrfn -> featnames.LINEARID featnames A table of feature names. Each edge (line) can have ...


5

The Short Answer: No. Census Tracts do change over time (Especially from 2000 to 2010 when in many cases they appear to be essentially redrawn). You can use the faces files to compare the same geographic area with its 2000 Census and 2010 Census assignment using dissolve techniques. You can also check out the relfiles to compare 1990 Census with 2000 Census ...


4

For just the state boundaries, you can download data from data.gov. If you're interested in the actual OSM data, you can download it at cloudmade, but it takes some processing to work with and is a fairly complex dataset.


4

A bit old but vaild. http://www.census.gov/geo/cob/bdy/cc/cc00shp/cc99_d00_shp.zip http://www.census.gov/geo/www/cob/cc2000.html


4

You can use QGIS to work with Tiger data. It's not the newest but this video shows how to get QGIS and load Tiger: http://www.youtube.com/watch?v=EQdMTXEFtaA


4

Downvote me if I'm wrong, but the GEOID is a concatenation of a bunch of fields as noted in the summary file documentation on page 13. In the geographic area codes, you'll be looking for fields at positions 26-65.


4

If you turn on On the Fly Projection in the Options, that will make sure layers with different CRS's will line up correctly, assuming they have the correct CRS assigned.


4

NHGIS has historical and modern census data, American Community Survey and GIS boundary files. It requires a (free) account to download data.


4

Since you have PostGIS 2.1.1 you're ahead of the game. Make sure you have wget installed, it is what will download the data from the Census FTP site. Create a gisdata directory with: sudo mkdir /gisdata Use chown and chgrp commands to change the ownership and group of /gisdata so that your normal user can read and write to /gisdata. Start psql and ...


4

The source data is available at http://www.census.gov/geo/maps-data/data/tiger-line.html. Note that the 2000 series tab provides data in the old ASCII format, but you can get the Census tracts by US state for 2000 in shapefile format from a page off the 2010 tab. Other than that, I can only suggest contacting ESRI.


3

If you need a gridded data set CIESIN's Gridded Population datasets may be of use. See http://sedac.ciesin.columbia.edu/gpw/aboutus.jsp#aboutTable for more details. The best resolution is 30 Arc seconds.


3

Tiger/Line is only as good as the data submitted to it; there are commercial vendors (TomTom/TeleAtlas or Nokia/Navteq) that are much more accurate but also will cost you several thousands of dollars. For free geocoding/routing of data your good choices are highly limited.


3

You don't say if you are using esri or not. ESRI Products come with a "data and maps" dvd. It is not in shp but can be selected and converted to shape using arcmap. I installed mine on a network drive in the mapdata folder. The rest of the path is like this. G:\MapData\ESRI_Data\streetmap_na\data\citylim.sdc


3

I have been using the 2010 TIGER shapefiles extensively and found the transition easy. The basic change is that what used to be separated into different shapefiles is now contained in a single one: rivers, roads, special places, railroads, everything. The [MTFCC] field tells you what's what. All the roads have an "S" prefix; e.g., S1100 is primary roads. ...


3

I have spent a lot of time mapping block groups and found that rendering them as tiles is usually the most efficient option. Client Side Flash Rendering: Max = Counties The most detailed geography you can reasonably expect a client browser to render on a national scale is US Counties and even those require significant optimization. The NY Times has a ...


3

Isn't this as simple as your database storing coordinate pairs in the format of x y and not lat lon (which would be y x). If the db used the format of lat lon, how would it handle other coordinate systems? If you look at the MySQL docs, it appears that the point class has an x property and a y property. ...


3

I realize this is an old question, and you may have an answer. The problem is that ZIP codes are defined by the Postal Service and change constantly. Also, Census wants geographies to be continuous, integral, and comprehensive; the ZIP code is none of these. At its heart, it is a list of addresses and not an "area." Census does realize, however, that many ...


3

Address locator Style field, select “US Address Dual Ranges.” For Reference Data, select “Streets” from the drop-down menu. In the Field Map area, make sure that every field with an asterisk has an entry under “Alias Name.” The field for Street Name should be assigned to FULLNAME. source: ...


3

Here is a bit of totally untested code that might work for you: import arcpy feat1 = 'finished_feature_class' feat2 = 'spatially_joined_feature_class' with arcpy.SearchCursor(feat2,['name_of_place_field','name_of_county_field']) as cursor: # create a dictionary to hold our place/county data places = {} for row in cursor: place = ...


3

I've had that exact problem trying to open the block group geodatabases and the problem seems to be two-fold: The width of the data exceeds a dbf's limitations (which I think is 32,767). This is a problem for the block group geodatabasescthat have 1,877 fields. The geodatabases that were created using ArcGIS 10.1 have compatibility issues running in other ...



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