364
1. Importation of images: Due to the fact that the
images were provided in CDROM, the first action was
to download them to the computer hard disk, converting
them to the software used format.
2. Preliminary hardcopies: in small scale to choose
and identify the grown control points (G.C.P.) that will
be used for the image georeferentiation and
rectification.
3. Control Points Selection: almost 18 points were
selected per image, having in mind that the points
would be as close to the borders as possible and the
same point fall in the neighbour images too. The other
factor to have in mind is the proximity of the points to
any point of the Provincial Basic Net, meassured
recently.
4. Recognition and Survey campaigns: consist of the
vinculation with GPS(Global Positioning System)
between the selected points and the Provincial Basic
Net points. Also, in this field outgoings pattern
recognition and identification were made, which are
viewed in the images to add them in the charts as
orientative information referent to the diferents land
uses.
5. Field data processing: include all the cabinet works
needed to obtain the GCP coordinates.
6. Image Rectification and Georeferentiation: This
stage involve the process from the point marking in the
images to the end when the image is appropriately
rectificated.
(M.G.I.), 30’ of width and 20’ heigh in our case to obtain
1:100.000 scale charts.
8. Charts edition: Consist of surrounding the cut piece
into the sheet, overlaying the corresponding quadrille
mark whith the plane coordinates, adding all the
marginal information, etc.
9. Images mosaicking: This process consist of
overlapping, verification and eventually the colour
adjustment of neighbour images, when they fall into the
same chart frame.
10. Plotting: Finally the edited charts printout operation
is issued.
METHODS AND MATERIALS
In this work we used a total of 11 (eleven) images Land
Sat TM, 7(seven) of which were provided to the
province by the National Hidrics Resource Segretarie.
This year the province acquired other 6(six) images,
4(four) of them cover mainly neighbour provinces areas
(Chaco, Santa Fe and Cordoba), with small pieces of
the east and south of our province; the other 2(two) of
them were used in replacement of 230-78 and 230-79
images of 1994, in which we detected important
defects.
We can see the information of the images used in the
following table:
7. Image cuting: The rectificated images are cut
through following meridians and parallels lines, whose
size is established by the Military Geographic Institute
ORBIT
DATE
ROWS
COLUMNS
BANDS
230-78
27-04-97
5760
6920
2,3 y 4
230-79
27-04-97
5760
6920
2,3 y 4
230-80
24-07-94
5920
6475
2,3 y 4
229-78
17-07-94
5920
6484
2,3 y 4
229-79
18-08-94
5920
6480
2,3 y 4
229-80
18-08-94
5920
6475
2,3 y 4
229-81
04-04-97
5760
6920
2,3 y 4
228-78
28-03-97
5760
6920
2,3 y 4
228-79
28-03-97
5760
6920
2,3 y 4
228-80
11-08-94
5920
6475
2,3 y 4
228-81
13-04-97
5760
6920
2,3 y 4
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